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Say My Name – Australian Native Botanicals

June 8, 2020

Life unfolds in layers,  a therapist once told me it was like peeling an onion. She left it at that but I then went home and peeled an onion realising that there are far more layers to those things than it appears at first glance and, more importantly, if you keep on peeling you eventually get to the heart of it – or nothing – either/ both are significant and gave me the ‘aha’ moments that I’m sure the therapist intended.

After moving to this country from England just over 16 years ago now I’ve found the same to be true of the bush.  In the first few years it was just greys, browns, muted greens and yellows under an azure blue sky that never seemed (to my English sensibilities) to give us rain.  Over time these blocks of colour which at times (I must admit) looked totally dead to me, have sprang to life, sometimes so much so that even in the middle of the scorched earth droughts that we are more frequently having here I am able to see opportunity and hope – well, I have to admit that sometimes that does take some doing.  In any case, the long and the short of it is, the more I’ve paid attention,  invested in this land, watched it and been interested in it, the more it has opened up to me.

I’m not good at remembering the names of things or people to be honest. I’m often quite distracted and somewhat ‘away with the fairies’ when details that I must feel are somewhat less important a use for my brain capacity are offered up.  Plant and Tree names also fall into that category and as such I have to look everything up a thousand times, write it onto my photos and in my journals before I even stand half a chance of internalising it and keeping that data attached to its subject.   I had been wondering why this was when I stumbled across a plant in my garden – a weed really but something I’m quite fond of – Shepherds Purse:

Apparently this is Capsella Bursa- Pastoris, a plant belonging to the mustard family (Brassicaceae).  This plant grows well in the UK and as a child I used to collect the little heart shaped ‘purses’ and try to figure out (using my imagination) why and how shepherds used them as purses.  I can’t remember ever coming up with a logical reason so ended up believing them to be fairy purses instead…

If you would like to hear more about the English Folklore remedy side of this plant this link is helpful.

Anyway, the moral of this story (for me) is that it didn’t really matter to me what this did, what it was (botanically) or what value it had (outside of my head), I’d formed an attachment to this that meant I would never, ever forget it and would always spot it when it was within my presence).  How would I with my now part logical and task-orientated, part ‘away with the fairies’ brain form similar life-long attachments in this new country where I have to make up my own names and stories?  How indeed…

Say My Name.

I realised later on that I didn’t make up the name ‘Shepherd’s Purse’ I’d inherited it from my mother just like she had and so on and so forth.  The name I know this plant by has history and culture, my culture attached to it and while I have never (until this point) looked any further into that side, I had an unspoken understanding that it was there and that it was bigger than I was, that I could tap into it and un-peel another layer of this story whenever I was ready.

Names unlock stories.

When it comes to Australian Native Botanicals I’ve found myself buying botany books, checking LUCIDCENTRAL or the EUCLID database for clues (Eucalyptus Identification Key) while cross referencing back to the common names like ‘blue gum’ or ‘green hood’ or ‘spear grass’ etc.   As a cosmetic chemist I could be forgiven for thinking that these are the only names that matter – damn, I could even go so broad as to group a whole family of essential oils under the convenient banner of ‘Eucalyptus’ and get away with it but I don’t want to do that, it doesn’t fire my imagination or open up new layers for me.  I sometimes think that the world has let its layers grow thick and old, that the layers that once could be peeled away with a careful fingernail now need a bulldozer to dislodge.  Losing the nuance, the detail, the connection makes for a harder, duller and less exciting world and that’s why I’m back to the names again but this time it’s not the fancy names, its the other stuff.

A little on the fancy latin names.

For me, identifying as white is identifying with being ‘white washed’ or culturally detached. I see that most clearly in botany with the use of Latin names.  I’m not from Italy, my bones never came from there.  Even if they did, my story didn’t start and end with the Roman empire so why wholeheartedly adopt it?  Clearly there are reasons why Latin is littered through ‘our’ culture, I couldn’t have got this far as a scientist without sucking big chunks of it up and sure, it’s useful but it isn’t all there is, it isn’t even the half of it and (as I’m finding out more and more) it is often the case that the eyes that first categorised nature using this whitewashed language didn’t ‘see’ the whole picture and as such, have disregarded part of its story. As a very short aside here I’ll mention ‘microbiome’.  Not at all a tangent I want to explore in this blog post but relevant nonetheless – that we can describe the skin without thinking of the microbes that are not us but that help us thrive.

Aboriginal Land, Aboriginal Names.

There isn’t one Aboriginal language, there are many.  Languages attached to each of the 500 or more nations that Australia was before becoming what it is today.  Finding the appropriate Aboriginal name for a particular plant is not an easy task as a plant can grow across many nations and have many names, a large proportion of which are not written down or recorded in a western way (because these are oral traditions based on stories).  This fact has made it challenging for Aboriginal elders and custodians to gain recognition for the body of evidence behind the therapeutic qualities of their plants.  Historically it has been much easier to gain TGA listings, develop international markets and collate bodies of evidence when using ‘white words’ – Latin names and ‘white’ processes – scientific analysis.  As a scientist I see a value in the process in which I’ve been trained and naturally adopt in my own investigations, however, one doesn’t do everything scientifically just because you can – eating, drinking, loving, art making etc require a little more than that.  On that theme it has also been easier to start trends within the cosmetic market when using ‘White’ common names – Kakadu Plum vs Gubinge or Murunga? I think that should stop now.

I am concerned at the growing level of detachment that’s crept into Australian Native Bushfood use, indeed it isn’t even the case that brands wanting Australian Native Ingredients care if they are grown here and many aren’t.   Captain Cook brought Joseph Banks, a botanist with him and from that moment the secrets and natural world intellectual property of Australian plants were exported all over the world without a glance back at their bigger history or cultural significance.  This has, of course, been the case the world over. It’s part of the ‘white wash’ narrative of our history but we don’t have to continue that into the here and now or future.  We do have a choice about what we do next.

Re-connecting plant with place, seed with story.

The first steps towards knowing the name of a botanical you have or wish to get to know/ use in your cosmetic is to work out where it is from/ on whose nation does it grow?  I live on Dharug land when I’m in the Blue Mountains and the language around here is either Dharug or Gundungurra. It’s Wiradjuri country that I live on when out near Wyangala Dam in the Central West, NSW.  So for me I have to look to two or even three languages for names – already harder than just going ‘what’s the latin name’ but worth it.   From my limited work with Aboriginal women who are still actively connected to country the value of keeping these ‘real’ names alive is immense and the pain of reducing them to their ‘white’ names is unbearable.  That said, sometimes it is inevitable that this happens given the history of Australia and where no local name is known we can at least leave some space for it to sit in when it is ready, when that layer is peeled.

Becoming aware of Aboriginal Australia and investing time in re-connecting plants to place, seed to story in a way that is respectful and humble is something I feel we should all do.  Sure those of us who are used to just jumping in and giving it a go, ego’s boosted by our whiteness and ‘oh she’ll be right’ attitudes may get it wrong sometimes but if we at least try, if we stay open to learning, if we open ourselves up to the possibility of this then we can’t go far wrong.  Hopefully, over time we can all encourage those that still hold the language of the plants we enjoy to share some of their stories with us, either  in language or using ‘white speak’ as a medium.  That would be amazing as one can only truly broaden the narrative if we let everybody tell their own stories.

For my part I’m now combining the common, botanical (Latin) and Wiradjuri or Darug names on my plant species I distill and extract from and will be investigating how I can connect with the people who know these names best to help tell their story either on this blog or on a platform of their choice.

Quick Summary take-home tips.

  • Plant Names =  place + plant (botanical name/ species) = Appropriate Aboriginal name.
  • Cultural use = there isn’t one, there are many so try not to refer to ‘traditional use’ of a plant as a catch-all, go further and see how the people you sourced it from used the plant.
  • Supply Chain = Check that what you are buying is Australian Grown, further check if it was grown and supplied by an Aboriginal owned business, few are)
  • Fair Trade =  Australia doesn’t necessarily have a fair trade system for its Native Australian Botanical supply chains but be aware that those who wild harvest the plants as part of their traditional practice may not be fully briefed on the true value of what they are doing and what happens up the supply chain.  Only the individual nations Elders can speak to that and that data isn’t always available.
  • Value your resources = Try not to reduce Australian botanical ingredients to just ‘fluff and bubbles’ let your product be an access point for a deeper, more connected relationship to country.

Eucalyptus Blue Gum – Eucalyptus Deanei.  The Dharug word for Eucalyptus/ Gum Tree is Yarra. The Gundungurra people call Eucalyptus trees Yerradhang.

A good Dharug word learning website is this.

The story goes that the blue mountains are that way because of the evaporation from the gum trees.  As you can see, the oil from the gum tree that grows in my garden does confirm that story to be true.  It’s just a shame that the oil sold in the mountains is not this species so you can’t come here and take this home with you, you just have to keep coming back 🙂

NB:  Interestingly enough after writing this I have spent the day searching for the correct names for a number of essential oils I’m working with.  In doing so I found this blog post.  Looks like I’m not the only one with this idea- they even got there first 🙂





Colours from nature.

May 26, 2020

So another little thing I like to do is to find colours in natural materials – plants, minerals or whatever.

Not all natural colourants are safe or good for use in cosmetics.  Take these mushroom dyes for example,  I’d want to do a whole lot more chemical analysis on them to make sure they were safe before putting them anywhere near my face, especially as a) I’m very amateur at picking the safe shrooms from the ones that will blow your head off and b) mushrooms can easily carry bacteria on them, not all of which is the good stuff.  However, it’s nice to play around and these dyes can always be used to colour fabrics (which is what I’ll do with them).

If you wish to use natural colourings for your cosmetics do make sure you check on their safety – are the extractions you make clean?  Are the chemicals that make the natural colour or anything else present in the brew potentially irritating to the skin?  Will the colour fade over time or when you change the pH of the product?  Will the colour stain the skin?

I once sat cutting up green walnuts with the view of making a dye out of them for use in fake tans (as that was and still is something that is used).  Unsurprisingly after sitting for a good hour or so and processing my nuts I looked at my hands to find them stained all over.  Sure Walnut is a great skin stainer and yes, that’s good for self-tanning solutions that want an instant skin tone but damn it makes you look like you have a nicotine habit if you get the dose and exposure time wrong.

The key with anything is to check, check and check again.  Do your stability testing, send things off for chemical analysis,  do a micro check and check for INCI/ botanical name data that could give you any clues as to where, how and when this has been used before.

On another note, as I was processing these mushrooms I did find that some of them do soap up pretty well, producing quite long-lasting bubbles.  Many plants contain natural Saponins and some of these can be harnessed by cosmetic chemists and used as surfactants.  I will have to do a lot more reading before I can ascertain whether what I’ve found has leg as a stand-alone mushroom soap agent but you never know!  Unsurprisingly some mushrooms also contain glutenous, gelling agent type chemicals (long chain sugars usually) which may be useful in thickening cosmetics.  Finally there’s beta glucan, a moisturiser and skin soothing agent, in mushroom cell walls and that’s already extracted by some cosmetic ingredient manufacturers.  I wonder how hard it would be for me to isolate it?  Maybe that’s a project for another day too!

I’ve put up my project pictures here- the blank spaces bug me, they really do but I can’t get a grasp on what these ones are yet so there you go!

No doubt my attempt at identifying some of the species has gone a bit off-track so if I do become aware of any errors I’ll let you know. I used a local field guide,  my notes and links from my local landcare group whose Fungi identification course I just attended on the weekend plus the powers of my own mind (hahahahaha) to ID these babies.   I also had much better pictures of the key features to refer back to from when the shrooms were fresh plus the now partially dried-up samples that I kept to refer back to.  Hopefully over time these little babies will teach me more about themselves but for now I’m just going to leave this right here.

No mushrooms were smoked or otherwise ingested in the making of this exciting blog entry  I don’t do drugs, I am drugs (a saying that I relate to and one first said (if the internet is true) by Salvadore Dali). Also all of these were found on our Fox Hill Hollow property.  Mushroom picking in natural parks requires a permit and is not really a good idea as if you take all the mushrooms the fairies become homeless.


The finished dyes tested on silk.  The darker one on the far end is made from Eucalyptus Red Gum (E.Blakelyi) which is the dominant species on our block. Well it’s either that species or it is the Camaldulensis (River Red Gum).  After thinking it was the latter for the last three years I’m not inclined to change my mind but I’ve got to wait until the buds and flowers come out to really get an better review done.  Anyway, it makes a lovely light pink to purple tone dye.

This is a great resource for people in Australia who are wanting to make dyes from Eucalyptus tree parts.  I used the bark to make this so it’s turned out pinker than the leaves.

The Quest for the Perfect Leaf. Eucalyptus leaves and essential oil production.

May 26, 2020

I am not an expert at producing essential oil, maybe one day I will be as I’m spending a lot of time practicing the art of distilling,  experimenting with different leaf-picking, prepping and stuffing strategies and, when I get the time and manage to post them off, evaluating the chemical analysis (GC traces) from the few ml’s of oil that represent the fruits of our labour (the tree and I).

My husband and I purchased (white words) a 50 acre patch of beautiful box woodland out in the central west of NSW about six years ago and because of that I have access to a range of different gum (Eucalyptus) trees and hopefully once our bush regeneration efforts have really kicked in, we may also get some interesting tea trees and acacias (wattles) to experiment with.  As interesting as essential oil production is to me I am not looking to become a scaled-up oil producer. My aim in this venture is both personal and profession and centres around my core life purpose which is to elevate (maybe only inside of myself as I have limited influence over others) the value we as humans attribute to nature, the natural rhythm of life and the relationship between the resources it provides us and that which we give to it.  I just choose to apply that value to cometic science and as such, use that platform as a way to interpret what I see, feel, hear and learn.

Personally I’ve always found my mind becomes both quieter and sharper when immersed in the natural world.  I have both mind (very, don’t worry) vision and hearing impairments plus an ADHD wired brain which do contribute to the overwhelm and  palpable disadvantage I feel when placed in rushed, man-made spaces.  However, out amongst the woodlands of the central tablelands of New South Wales I tap into a whole other set of senses that see me pick up on the tiniest of fungi, the slightest whiff of an animal in the distance or the subtle changes in bird song as a predator (usually me unless I stay still long enough) comes closer.  This feeling of heightened awareness is addictive and is rewarded when nature opens up its arms and shows you more and more of its secrets.  What was once brown and green becomes different Eucalyptus species, what used to just be a stringy bark all at once becomes an ecosystem in its own right with soil fungi, birds, bees and echidna scratchings digging up the ants nests.  It is this level of attention and intent I bring to my essential oil practice and it is with the whole ecosystem in mind that I pursue this phase of my cosmetic chemistry journey.  As temporary custodians (much better word than owners) of this tiny patch of the planet I feel that interpreting this land through my cosmetic chemist eyes is the best way for me to protect it and share its value with the world.

The Quest for the Perfect Leaf. 

So recently I’ve become more interested in understanding how the age of a Eucalyptus leaf affects oil yield, understanding that the answer may be anywhere from ‘it doesn’t’ to ‘hugely’ of course.  What I’m finding out so far, and there is a lot of reading, comparing and looking for gaps and cross-overs (research, that’s the research part), is that it is likely not so much of a question of how old the leaves are but at what development stage they have reached.

I am no plant specialist either so bare with me while I excitedly share the rudimental understanding of where I’ve got to on this quest to identify the perfect leaf.

Eucalyptus leaves through their growing stages and ages. 

These leaves come from the same tree, one of the Eucalyptus trees that is growing on our driveway at Fox Hill Hollow.  The tree is currently about 2 meters tall and is in pretty good condition.

Eucalyptus trees grow all year round which is something that took a bit of a while adjusting to as I come from a place where trees have a natural break each autumn/ winter, dropping their leaves and going to sleep – maybe Australia is the land of 24/7 partying after all.  The top left are the tiny baby new growth and the bottom right is the fully-grown leaf shape.  According to this page in the book ‘Eucalyptus Ecology’ by Jann Williams and John Woinarski (and I don’t know if it applies to all Eucalyptus species) the average life span of a leaf is 18 months so maybe these leaves represent a 2-3 month development stage? If they do that would be great (but would also be a fluke as I’m only going by feel here).

As you may have noticed either just in these leaves or with Eucalyptus in general, their leaves can change remarkably between their baby and adult state.   While it is not uncommon for plants to have a juvenile and adult state, Eucalyptus really do take it to extremes at times.  When I first moved here I used to spend ages staring at trees trying to work out if some weird hybrid was developing, if maybe two trees were entwined to look like one or if I was just going crazy. Turns out that this leaf metamorphisis is just what Eucalyptus trees do and there are some important features attached to that ‘coming of age’ process when seeking out the ‘perfect’ leaf.

So, while you can see a change in size, shape and colour, you may not be able to tell that the leaves on the top row are all soft while the leaves on the bottom row become progressively stiffer due to a process called lignification.  Lignification is something I know very little about but it’s basically where a higher plant such as this Eucalyptus species produces an organic polymer (family of chemicals) called Lignin.  Lignin is a carbon-based chemical and is found across many plants, usually in their woody material where it helps to strengthen cell walls and keep the plants circulation functioning well.  The Eucalyptus tree starts off with very soft leaves but doesn’t take long to toughen them up in its bid to survive.  From what I’ve read so far, rather than the laying down of Lignin being just a biological-clock triggered process, it can also happen in response to trauma.  A good article on this can be found here.

Australian plants have to deal with lots of things nibbling and attacking them from fluffy animals right through to creepy crawly things and microbes.  They also have to deal with a rather harsh sun for long periods of time.   One of the tools the tree has to defend its self is its ability to lay down this hard polymer and stiffen its leaves up.  Stiffer leaves are harder to eat and are more resilient so it makes sense to invest in this protection.  However, for the essential oil hunter, this defence mechanism does seem to make it slightly harder to access the essential oil meaning that the perfect leaf for essential oil production may well be one that is fully grown but not fully lignified (as stated in the article I’ve linked to just below).

Here is a really good overview of the way different ages and stages of leaves have influenced essential oil yields. I do wonder though if the study that found younger leaves to contain more essential oil (as a percentage yield) were actually finding that or was it just a case of the oil being more accessible? I say that because other papers I’ve read have found the oil yield to be similar throughout the tree’s age.  As essential oil is produced by the plant for its benefit – it’s often designed to be bitter to the taste so animals give up eating it and contains anti-microbial actives so again, pests either die or are put off attacking it.  It makes little sense to leave your soft fresh leaves vulnerable on two counts – less pesticide (essential oil) and less lignification/ cuticle wax.  Anyway, that’s what I’m trying to dig into more deeply now.

Cuticle or epicuticular wax is another thing that may reduce the ability of an essential oil distiller to access the oil within the cell.   This paper is about floriculture but it does look into the variability of waxes between Eucalyptus species and how the wax levels vary with leaf age.   This paper is also very interesting as it looks at the chemistry and differences in thickness of wax between two common Eucalyptus types.   

Maybe I’m looking to find the wrong word but I can’t quite work out yet if the amount of wax (percentage wise) changes form young to older leaves, I have read that the structure of the wax develops over time but that’s not quite the same thing.  To me, so far, it looks like the epicuticular wax is performing a role similar to either a raincoat or sunscreen or both for the leaf.  The chemistry of this wax is definitely determined by the species of Eucalypt but I feel it likely that the amount of wax expressed is there in response to the environment rather than age although I may be wrong. Further, over time, these waxes have been shown to change.  Maybe the waxes get a chance to polymerise…  This happens sometimes with essential oil chemistry, some compounds react with each other over time, turning what was a liquid essential oil into a thick resin-like substance.  Anyway, the long and short of this part is that I don’t feel at this point, that the wax protection layer is as much of a barrier to finding the perfect leaf as the lignification is – as odd as that may seem given that wax is waterproof and we distill essential oils using steam to which the waxes may be somewhat resistant… I feel the waxy layer could be a barrier to distillation of some species, but within a species less of factor in choosing to distill young, middle-aged or old leaves.  What looking at this has given me an appreciation for is the potential role that a solvent other than steam/ water could play in improving oil yield in some species.  Maybe leaves could have a cold wash with a surfactant to remove some of the wax before distillation?  I’m not sure how that would go,  solvents like hexane are often used in the papers I’ve linked to but most people don’t want mention of that in their oil distillation and I completely understand why.

So where are the perfect leaves then?

When I consider waxiness, leaf size and leaf stiffness I’m edging towards the perfect leaves being those that have just taken on their adult form and are well developed although not fully grown but still retain the softness and flexibility of their youth – pre lignified leaves.  I don’t know what age that is for the trees I have but I know how they look and feel – probably top right and/or bottom left (just getting harder). Another thing to consider is leaf physical condition – as stress toughens the leaves up, maybe prematurely, I feel it is important to stress that undamaged leaves that haven’t been too stressed by sun, wind, frost or nibbling things are going to be easier to work with than less pristine leaves.

Testing my theories. 

The next step now is for me to try and collect enough of the leaves at those intermediate stages to distill in a meaningful and scientific way (or as much as possible) and then compare that with a fully grown leaf distillation round.  A rough go at that may give me a bit more insight into the perfect leaf or it might just send me batty. Either way, I’ll end up with a bit more essential oil and a good amount of hydrosol to play with which doesn’t sound too bad at all.  This may take some time to do but I’ll see what I can come up with.

In the meantime the perfect leaf for oil distillation is not too soft or too hard, not too big or too small and hopefully in great condition.  My guess is that it is also probably around 9-11 months old (well, for my type that is, yours may be different).



Research and Reading are not the same thing.

May 24, 2020

I know, I know, a long time between posts again but things are changing around here and I’ve had lots of non-blog things going on.  I have still been thinking about you, about this blog, about how I teach, about words and the meaning they hold, about how and what we read and how that informs our thoughts.  So, whether I like it or not, this is where the rubber hit the road this month – Research…


Can be used to identify a class of things including papers, articles, books etc

And with that I see the first clue as to what is going on and why it isn’t getting people very far. Best to start off with this doing bit as that’s what people tell me they have been doing with their lives, often for years in their quest for knowledge (another clue maybe).
Investigate Systematically.  Two words that imply a direction and a method.  As a scientist I am immediately drawn to accept the challenge laid out within this definition as to me those two words get me thinking about ideas that can be probed and prodded by doing something.  Scientists systematically investigate things by first coming up with a hypothesis.  While there are many different ways of laying out a hypothesis, the simplest is often just a statement that positively or negatively relates one thing with another.  I’ll give you an example:
We could start with a big picture issue in the world,  maybe chemical pollution.  We could narrow that down to think about pollution in waterways from every-day chemicals.  We could then narrow our thoughts down even more to help us pinpoint our research target into something measurable and manageable.  Maybe we focus on cosmetic chemicals that could potentially be released into waterways every-day during use.  The activity I’m doing here is what I’d call ‘building the scope for an investigation’ or ‘getting my eye in’.   I am interested in pollution as a ‘big picture’ topic but realise it’s too large and broad a topic to ‘do my research’ on pollution per se, I have to narrow things down so that I can go deeper and test what I find – test is another important word. 
Up to this point I’ve not really had to do any reading (reading before research) as I’m still in the vague phase but sooner or later I’ll have to get more specific.
What I do have though, are two variables  that I could try and prove or disprove a relationship between:
Variable one: chemical pollution in waterways.
Variable two: Peoples cosmetic use.
Now I’m getting closer to a hypothesis.
I could hypothesise (state) that ‘the use of cosmetics causes chemical pollution levels in water to rise’ but that’s quite vague and could do with a bit of polishing. It would also need clearly defining – another important word.   A good hypothesis is one that is targeted and specific while remaining meaningful and testable.  Polishing our hypothesis is easier when we’ve done our background reading…
If we leave the examination of the term ‘research’ for a while and flip over to examine the word ‘reading’ you may start to see what I’m talking about.
Reading (definition sourced from here)
Reading is defined as a cognitive process that involves decoding symbols to arrive at meaning. Reading is an active process of constructing meanings of words. Reading with a purpose helps the reader to direct information towards a goal and focuses their attention.
Reading is a very, very useful thing to do.  As you can see from this definition, reading with purpose (being discerning in the texts you select) does help one to form a useful and relevant research hypothesis but reading by its self is not the same as research.  I’ll come back to that again as it may still be hard to see why.
If we think about the idea I had above, about a link between cosmetic chemicals and water pollution we could use our reading time to help us select tighter and more relevant variables and (very importantly) to define what we mean by ‘chemical pollution’ and (also very importantly) how we may tell if it rises or not.
Diving off the side for a moment.
The subtle detail of what I’ve just said above is what is frequently lost when a scientific method of investigating is not followed.  It may seem pedantic to spend hours going off on what seems like a tangent to work out what ‘chemical pollution’ is when you have a gut feeling OR have read a few MSDS’s and already know that some of the chemicals used in cosmetics can cause damage to aquatic ecosystems.   It seems entirely logical, especially if one has seen the ‘campaign for safe cosmetics’ video  about garbage in-garbage out – that if you only make cosmetics with natural ingredients they will either cause less damage than ‘regular’ cosmetics or (fingers crossed) none at all.  Why bother painstakingly defining what you mean. Pollution is pollution is pollution.  Only of course it is not.
Same goes for how we may tell if it rises or not.  Where, when, how often, by what measure – these are all critically important when trying to compile a data set that gives you results that can be compared.  I’m sure you’ve heard the term ‘comparing apples with apples’. well if the data that you collect is based on measurements taken using different metrics then that’s what you are doing.  Again, sounds like a case of ‘computer-says-no’ (Little Britain reference if you want to Google it) but it isn’t.
To say the devil is in the detail is not at all over-dramatic here.  This stuff really matters and is why when I create something like my ‘oil table master data sheet’ it takes literally hours and hours of sifting through data, converting figures,  checking on methodology,  finding alternative sources that use the same methodology and get comparable results etc.  That’s research,  if I just ‘did’ reading I’d have ended up with a mish-mash of bull-shit.
Anyway, that’s enough of that, back to reading.
Reading Comprehension.
This is easy when we are reading every-day things like a blog, newspaper, website or magazine but very tricky when you start diving into academic literature which includes scientific reports, medical journal data,  meta data analysis and other technical data.  For this type of reading a lot of prior knowledge is necessary to be able to comprehend what is being said in order to then make an informed choice as to what to do next.
Cosmetic brand owners may read technical data from time to time to help them compare one ingredient with another and make a choice as to what’s better.  A good example of the type of data that might be accessed in relation to the ‘chemical pollution’ hypothesis we are trying to form could be MSDS (Material Safety Data Sheets).   These are a good starting point for getting a feel for the safety of individual cosmetic ingredients.  If you decided, for example, that you would become very specific and narrow your ‘chemical pollution’ hypothesis down to shampoo use you could do some reading of websites, product bottles, magazines, blogs or whatever to get a feel for the types of shampoo that people are using.  You could then compile a list of all the chemicals that are found in these formulations, source MSDS for each and then compare them.  Sounds very simple and indeed, this is exactly what some people do.  However,  did you notice that not all MSDS sections for environmental impact are filled out fully,  those that are completed don’t all use the same metrics to report their data and, very, very importantly, unless you are a really experienced formulator you’ve likely no real idea of how all of these different chemicals relate to one another in a formula – do people typically formulate that chemical at 1% or 50% of the formula?  How common is its use?  In shampoos made with these chemicals is their in-use performance excellent, average or poor compared to other products and does this lead to people double-shampooing?  If so, that could change what comes out the other end.  Are some ingredients targeted to people with specific hair/ scalp issues or is everything equivalent?   See how difficult it becomes to APPLY something as seemingly simple as MSDS data to your project and we haven’t even gone into things like LD50 values or what terms like biodegradable actually mean in this context.
The bottom line is that reading is easy, comprehending what you are reading fully is harder,  comprehending that reading in relation to building a hypothesis is even more difficult and actually performing comparative data analysis (which is a research step) is right up there as a very hard thing do to.
In terms of educational level you’d be looking at reading going from primary school level (most blogs, magazines,  popular news sites and websites etc) to maybe a year 12 (18 year old ish) level for some more popular science publications and supplier technical data sheets including MSDS (with appropriate training behind you) to Degree level for the curation of basic science publications including conducting a basic to intermediate level of research to investigate a hypothesis.  Masters degree level is where research gets more thorough and more complex relationships can start to be investigated culminating in a PhD when both reading and research is at a level where it can really break new ground in a very thorough and deep way.
Another aside-Maths.
People find maths difficult, I know this because I see enough people (who have businesses BTW) who can’t ‘do’ percentages.  While this is nothing to be ashamed of, it is concerning to me as a scientist and business owner (if you can’t ‘do’ percentages how do you know what level of profit you are making (if any?) let alone be able to tell if your formulas are safe?).  If you are trying to create a brand or a product even that is better than something else in as much as it is a safer (broad statement but commonly used) than a ‘regular’ cosmetic you have to, at some point, use maths to interrigate that, to work out if your product/ brand actually IS safer in a statistically significant way.  There really is no other way around it if you care about being ‘evidence based’ and truthful.  Gut feelings, hunches, popular opinion and ‘common sense’ don’t make for robust science-based evidence.
Another aside – how does it feel?
Picking up from my last point that these gut feelings, old-wives tales, popular opinion or whatever aren’t ‘science’ they are not nothing.  These things help us inform our direction by pointing us to areas where people need solutions or clarity. To put it simply, these alternative conceptions/ ideas or solutions are opportunities.
If people don’t trust mainstream products to keep the waterways chemical-pollution free then there is a problem. It may purely be one of perception or, more worryingly, it may actually be reality either in part or in full.  Listening to what people ‘chatter’ about and how they instinctively go about solving the problems they come across is like gold dust to the commercial chemist.  We need to listen, un-pick, critically evaluate and then RESEARCH to fill in the gaps.
So research and reading are not the same thing.
Reading helps you to understand where things are at, to get a feel of the landscape and to start informing you of where the gaps and/or opportunities may be.
Reading research from other people and curating it is useful and is something that many scientists (me included) do – that’s what this blog often tries to do.  However, doing this involves a scientific process and the ability to discern scientific information and make sure you are comparing or compiling a list of apples and apples so you can build a logical and scaffolded solution.
Reading to inform a hypothesis that is meaningful and that can be investigated in a scientifically robust way is something that takes considerable skill and prior knowledge, including, in many cases, an understanding of and ability to interpret statistics and other mathematical data. These are the skills you learn and develop through Degree and Masters Degree studies before exploring them deeply in a PhD program.
People without these qualifications can, of course, ‘do’ research but it helps if there is not only an awareness of what ‘doing research’ means but also an appreciation for its complexity and challenges.
I hope this has been somewhat helpful and that it encourages you to concentrate on developing the best hypothesis questions you can.  Once you’ve mastered the art of hypothesis building, researching becomes somewhat easier and more targeted and, with a good hypothesis you would find it much easier to get help in working through any difficult bits of information you stumble upon.

Moving online – the dark side of watching others.

April 18, 2020

I have been teaching people cosmetic science stuff for almost as long as I have been doing it myself, a good twenty plus years. While that seems weird now I say it, that I started off teaching even BEFORE I really knew how to explain the intricacies of what happens in a cream when this chemical meets that, it really isn’t weird at all.  Those of us who teach in the true sense of the word know that teaching isn’t really about what you know or what you say, it’s about what you can inspire others to DO.

It’s that knowledge that has led me to here.  A place where I’ve been a little stuck between wanting to do something to solve a problem that we currently have in the world and knowing that the easiest way to jump on and do that will probably be the worst way possible.  What I’m talking about here is online classes, the type of class where you sit back in the comfort of your own home, maybe even in your own time and just watch an expert (or at least someone you perceive to be an expert) at work with the view to having that knowledge permeate your body through the screen and infuse your cells with this new ability.  Easy, perfect, sweet and convenient.


When I’m in my lab I often listen to podcasts that I download from the inter webs.  One of my favourites is called ‘Hidden Brain’ where host Shankar Vedantam introduces his listeners to a wide variety of thought pinging topics, probing social issues, psychology, history, the human condition, society and everything in-between.  The podcasts official marketing spiel describes it as ‘using science and storytelling to reveal the unconscious patterns that drive human behavior, shape our choices and direct our relationships’.  Perfect for listening to as my hands are busy mixing up potions.

As is often the case with life, you are presented with what you need at just the right time if you happen to be paying attention (and quietly seeking and looking in the right places I suspect) and this week was no different.  I ended up with podcast running through my ear balls:  ‘Close Enough: The Lure of Living Through Others‘.

If you do have time to give that a listen do as it is quite interesting. If not, the gist of it is that watching others, especially ‘experts’ was found in scientific studies to result in people feeling overconfident in their own abilities.  Basically you watch others build a shed from discarded pallets, you think you can do the same, you find some pallets and you then feel like smashing up the whole house when your pallet shed falls down, you end up in the emergency room and instead of costing you a few dollars, the whole project nearly cost you your life.   Turns out same thing happens with cosmetic science.  Everything looks easy on the internet,  things don’t often go wrong or if they do it’s a simple fix to get it back on track, the product doesn’t grow mould and everyone thinks its ‘the best thing they ever tried in their life’.  Only those of us that have laboratories and do this for a living know this to be bullshit and that’s my problem.

So, life in the Coronaverse means we can’t travel to courses any more. I was actually supposed to be running a course today, ironically this particular course has been postponed twice already because of scheduling issues and now, this third time is completely out of our hands.  Only maybe it isn’t, maybe I can just put it all online and voila, job done, everyone happy.

But I really don’t believe that…

Putting up a set of slides and recipes and narrating them before posting them online is one thing, actually taking the time to re-frame and organise that same content in a way that allows now isolated students to gain confidence and feel adequately supported so that they can  take what is taught and apply it in their own creative ways is another thing entirely.  I’ve been studying science teaching as a masters degree for a year now and can absolutely attest to the fact that it’s student’s (any age of student) misconceptions  that trip them up and if you can’t see them (because you as the teacher aren’t watching their faces as you teach), can’t anticipate them (as you’ve never sat with someone who is learning this stuff before) or can’t challenge them at that point where you spot a teachable moment then you are not teaching at all, you are just ‘chalk-and-talking’ which is more lecturing than teaching, the type of lecturing that trains students to expect knowledge to be injected into their brains by you, their guru, with minimum fuss and effort.  Not best practice, not at all.

But this week felt like crunch time. The customers kept shouting out for something, I really do want to do something, something good and meaningful and the business could really appreciate something too but the answer remains what? What do I do?

With that in mind I turn my attention to how I signed off a couple of help desk customer emails this week:

‘Remember, creative cosmetic science is only 20% thinking and 80% doing until you know you are in the right ball-park.

Then it’s 40% thinking (to refine your idea) and 60% doing – the polish.

Finally you get to the 80% thinking and 20% doing with your sanity checking, box ticking and scale-up prep’

and that’s when I got my answer.

I need to make sure my courses remain hands-on.

I need to keep my core modus operandi in mind – and that’s one of narrative teaching – I can’t leave that to chance and chance is what I’ll be leaning on if I don’t actively design the ‘big picture’ narrative into my online courses. Slides and data just aren’t enough.

Finally I have to maintain enough contact with my students that I can challenge them, wherever they are. So it feels like I’m with them and noticing them, feeling their questions bubbling inside them and inviting them to share them with me.  That is hard to do through a screen but not impossible, I’m good at this, I know I can do it.

So that, my friends is that.  I’m going to give online teaching a go but I’m going to do it my way and my way doesn’t involve you sitting back with popcorn while you watch me,  nope, in my classes I’ll be inspiring you and then I’ll be sitting back and watching you with my two beady eyes and my probing questions at the ready 🙂

Have you done any hands-on virtual classes? How did they go for you? What did you study and did you feel you learned anything?  I’m interested to know your experience as I’m not that good at online learning myself, I find it really plays havoc with my ADHD but that’s because of the way most of it is taught. But you are not me so maybe I’m alone in my struggles.

Anyway, watch this space and get your laboratory beakers and spatulas polished and ready because I’m coming to teach you a lesson hahahahahahahaha (and hopefully there will be no swearing in it 😉

Amanda x


Is Witch Hazel all its cracked up to be?

April 15, 2020

I’ve always liked Witch Hazel although I’ve never really analysed why.  I used to use it liberally on my acne-prone skin as a teenager and while I am not sure it did much good (I think most of my issues were internal rather than external) I’m not sure it did anything bad either.  However, what it did do is make me feel like I was doing something and that, it turned out, was enough for then.

Fast forward a few gazillion years and I’m here, staring at an email that’s come in from a client wanting a second opinion on this ingredient. Apparently another industry expert has lambasted this ingredient,  stating that most of ‘what you’ve read’ is anecdotal rather than scientific evidence.  It seems that the main concerns that this individual has with the ingredient are in relation to Witch Hazel’s tannins (that apparently are sensitising?).   Next, the alcohol which Witch Hazel is often supplied in is ‘never a good idea’ and finally that the volatile oil component of Witch Hazel contains eugenol (a bad, bad thing).

On reading this I felt a bit perplexed as there’s a lot going on here but no references (maybe the person requesting an answer to this opinion hadn’t cut and pasted the references or maybe there weren’t any, I don’t know).  There were certainly a lot of things to unpick and if I was to do this ingredient any justice and evaluate it properly I’d have to do a bit of a deep dive into some science and suspend my own bias as much as possible.  And that’s what I did.

On Witch Hazel in General. 

Hamamelis Virginia.

This herb was used by Native American Indians for burns and injuries although I don’t know how they prepared it, from which plant part , etc.  However, whatever they did made an impression as it exists in a few pharmacopoeia outside of the USA.  A monograph exists in the old British Pharmacopeia,  the German and Various Herbal Reference Books as far as I can see.  I did find though that in the US herbal ingredients are not regulated this way as they are treated as foods (I think that’s right, I’m less focused on the minutia of human law so you may want to double check that if you want to know the exact situation in the US).

It’s important to note that Witch Hazel extract isn’t just one thing.  There’s a powder made from the bark that could be brewed up in water and then strained,  there’s a bark extract made up in alcohol to get a fuller extraction there’s a leaf extract prepared in a variety of ways and there are fermented extracts.  It’s quite likely that there are  other presentations of this available as well but I couldn’t find any on this search.

The Witch Hazel I know best is the alcohol extraction, this generally contains a residual 14% ethanol carried over from the mashing up of the bark and the extraction of the phytochemical.  Bark material is quite hard and so typically needs a solvent with a bit more oomph than just water or even glycerin to soften it so that its chemistry can be collected, alcohol is just the thing.  I did find a paper on my travels that found the concentration of one of the Witch Hazel extracts, Hamamelitannin, to be 31 times stronger in the bark than the leaf and 87 times stronger than in the stem.

So from that we should address the alcohol part.

Alcohol (as in ethanol in this case) can be very drying to the skin.  During these COVID19 times most of us who have partaken in the alcohol sanitiser ritual will attest to that fact.  Alcohol can denature your skin proteins which is not a nice thing to have happen. When this happens it feels irritating although it’s important to note that alcohol is not a dermal allergen or sensitiser (people don’t become allergic to it).  Think of alcohol like you would think of a carpet burn. If you keep rubbing your skin at reasonable speed across a carpet you’ll get a burn because of the physical abrasion.  You could keep on doing that and it would keep on being irritating, your skin would probably not ‘get used’ to it although you may become less sensitised to that sensation (conditioning). However, you would not say ‘oh I can’t rub my skin on the carpet as I’m allergic to it’ would you?  Alcohol is the same but it applies its abrasion via chemical means.  The carpet rubs off your skin indiscriminately, alcohol messes up your proteins in a targeted and knowable way.

Not only does alcohol mess with your proteins, it’s also got solvency properties which is a double edged sword.  One of the reasons that alcohol is used with herbs is for its capacity to capture and hold onto plant chemicals so that they may be available to the skin or body (if you ingest them).  However, alcohols solvency doesn’t stop there, one reason why alcohol is a carcinogen is because of its ability to dissolve membranes (the protein thing above) but also because it opens the door (be that the skin or internal organs) to other things we ingest or apply with it.  So, if you have alcohol in your skincare, be aware that everything else in your skincare has now got options on an easy passage through to the deeper skin layers, whether the other chemicals take that ride or not will depend on their chemistry, abundance and the product type.  I mention this as there are various mentions of Witch Hazel in skincare formulations that have caused people to become irritated.  While it may be that Witch Hazel is inherently irritating,  I have my suspicions that the alcohol effect may be skewing things here – you can’t have super active Witch Hazel without alcohol plus most Witch Hazel formulations are targeted at ‘problem’ skin which may already have a vulnerable or compromised barrier. So are formulations with Witch Hazel in sometimes irritating because of the Witch Hazel or because of these other things? It’s not that easy after all…

So back to alcohol.

Sounds like a shit of an ingredient.

Well, it is and it isn’t. While I’d never advocate for a 100% alcohol rinse of the skin every-day,  it’s easy to find evidence to support the safe use of ethanol in cosmetic formulations.  Take the World Health Organisations work on hand sanitisers for goodness sake!  They found that adding only 0.5% of Glycerin to a 70% Ethanol hand wash was enough to counter the drying effects of the product while bringing no detriment to the antimicrobial action of the product.  I feel that if we can do that then most cosmetic products are not at risk  of being irritating because of alcohol. However I  definitely would check my formula to make sure there’s nothing likely to cause issues should it go on a road trip through the dermis because of ethanol.

In summary, the comment about ‘alcohol never being a good idea’ seems impractical given that alcohol actually helps us access many plant chemicals and forms the basis for practically all herbal medicines as far as I can see (either than or my herbalist is an alcoholic 🙂 )

Next, Tannins.

So apparently, the tannins in Witch Hazel are sensitising although I’m not sure from the piece I read whether that means all the tannins or just some.  The comment also suggests that Witch Hazel extract is around 8-12% of these chemicals which I guess could be quite a lot of sensitising active if you use Witch Hazel neat (which I used to do).  By the way, most cosmetic formulations use Witch Hazel diluted, using maybe 1-20% in a formula unless it happens to be a Witch Hazel Toner where you literally can just go all out with this as the only ingredient (Witch Hazel, residual water, Alcohol, preservative).

What are Witch Hazel Tannins then?


I like to name my chemicals as that’s always a good plan if you want to enable other people to actually critically analyse your data.  So it may be good to dive into this tannins situation a bit more personally.

According to Cosmetic Ingredient Review data (I’ve linked to this three times in total as it’s a really important paper) Witch Hazel contains between 3-12% Tannins (leaf less, bark more).

Apparently there are two families of tannins in Witch Hazel: Hydrolizable and Condensed.

Hydrolizable tannins are based on Gallic or Ellagic Acid.  

Chemically these phenolics are linked to a sugar molecule that can be split off by hydrolysis hence their name.  This paper also states that these are usually yellow/ brown in colour. 

Gallic and Ellagic Acid are well known cosmetic tannins.  Epigallocatechin Gallate (EGCG) is from the same family and its this that makes Green Tea so great.  Gallic acid was found in all thirty of these Aurevedic plants in this study so I’d be pretty surprised to find out that it was a bad guy.

Ellagic Acid is even nicer (my bias is showing here, I love sugar) as that’s found in lots of sweet fruits like Strawberries, Raspberries and Cranberries.

Then there is the Hamemelitannins which are abundant in Witch Hazel (as you would expect from the name). These are Gallic Acid types and these are powerful antioxidants as seen here. 

These Hamemelitannins get to the heart of what makes Witch Hazel special and different to other antioxidant rich extracts.  These have been found to be very powerful at protecting cells against superoxide anion as seen here and this free radical is important in dermatology because it’s the one that causes most extrinsic (environmental or premature) cell ageing.   It’s not often that Witch Hazel is touted as anti-ageing but based on the evidence there’s no reason why it couldn’t be sold in that way.

Condensed Tannins. 

Condensed Tannins are described here on your helpful Wikipedia page.  These proanthocyanidins oxidise too Anthocyanins and are typically the chemistry that gives fruit and vegetables its rainbow of colours.   I’m wondering if it is these that are being referenced as being lost in the distillation process in the comments I was reading.  I don’t know for sure but whatever the case, there’s still a lot of antioxidant activity going on in Witch Hazel after the extract is made to make this a valid (and active) tannin-rich active.

Witch Hazel Whole Chemistry.

Here’s a link to the whole chemical make-up of Witch Hazel and its range of extracts. As you can see this is quite a complex beast, not unusual for a natural ‘active’.  I think there were 168 constituents found in the volatile fraction of the bark which gives you some idea of how crazy it is to try and analyse this and other herbs to find out what, precisely is going on and that’s what I’m going to talk about now.

In the case against Witch Hazel we have evidence that people have developed allergic reactions to Witch Hazel Distillates from cosmetic application of Witch Hazel products.  The Cosmetic Ingredient Review that I’ve linked to above highlights the case of a 31 year old woman who tested positive for a Witch Hazel allergy.   However, it becomes less surprising that allergies can and do happen when you take note of the fact that a) this is an active for helping to bring somewhat dysfunctional or sub-optimal skin back to normal and b) it’s often presented in alcohol which helps the actives to penetrate deeper than they otherwise would and c) Unlike many herbal actives that are typically present in cosmetics at no more than 5% at best, Witch Hazel is often incorporated at up to 10-20% or even as the whole product and d) this is a very complex and very active herbal extract.

So is Witch Hazel Chemistry (tannins) bad?

Look, I’m having a very hard time in finding anything to justify that position on.  I do wonder if maybe there’s been a misunderstanding of some of the science data.  There have been a few toxicological studies where the tannins from Witch Hazel have been isolated and concentrated then applied to cells. While antioxidant results were amazing, even showing tumour suppression and other such effects, there was, in some studies some cell toxicity reported.  However, if you read the study as it was intended this is unsurprising and totally irrelevant to a topical cosmetic application.

And finally Eugenol.

Aaahhhh eugenol…

Now again if we look at the Cosmetic Ingredient Review data we get the information we need to work out whether a) this is present and b) if it is present, does it pose a threat.

CIR data shows that the volatile oil fraction of Witch Hazel extract is only 0.05-0.1% of the total extract.  Anyone who has used Witch Hazel will know it has some volatile oil in it as the extract has a distinctive smell but learning that the smell is coming from a maximum of 0.1% ‘essential oil’ is but a bit ‘wow’ and also quite reassuring in terms of potential irritation potential.

So Eugenol, this is the active component in Clove. It’s what makes Clove so good at mould busting.  However, Clove contains over 70% Eugenol,  Witch Hazel contains next to nothing.

In terms of whether this is good, bad or indifferent for skin I turn to Robert Tisserand’s ‘Essential Oil Safety’.  Here I am reminded that Eugenol isn’t the best thing to put on your skin with gay abandon but neither is it the worst.  A sensible 0.5% max dermal use level is cited by the books authors.  That said, we must note that the EU legislators have listed Eugenol as one of their 26 Fragrance Allergens and as such, it should be listed if present at over 0.01% in a wash-off and 0.001% in a leave-on product.

So how much Eugenol could you get from using Witch Hazel?

Let’s say Volatile oil fraction was at the highest end of the range – 0.1%.

Let’s say we use Witch Hazel extract neat.

So we have 0.1% of Volatile oil on our face.

Now if we look back at the CIR data we see that Eugenol typically makes up 0% of the Leaf extract (less commonly used) but a whopping 2.41% of the bark extract (typical).

So now our 0.1% of volatile contains 2.41% of Eugenol which equates to 0.00241%

If we were using Bark Extract neat and if that bark extract contained Eugenol at the higher level in an extract with the maximum volatile concentration for a leave-on application we would have a notifiable level of Eugenol in our finished product.  It would need to go onto the label so that people could see it and decide if the product was right for them – typically people with fragrance allergies may avoid anything with listed fragrance allergens.

However, if this worst-case scenario extract was formulated into a cosmetic designed for rinse off, there would be no need for notification.  Also, if this extract was used for leave-on at concentrations of up to 80% we would not have to notify anyone.

That doesn’t seem like a massive risk to me whichever way you spin the data.

So what’s the bottom line for Witch Hazel?

As far as I can see there is, has never been and should continue to be no problem in using this ingredient either as an ingredient or as a product in skincare for leave on and/or rinse-off applications. I just can’t really find anything compelling me to suggest otherwise and have, instead found quite a lot of data to support the use of Witch Hazel as an antioxidant, anti-inflammatory,  for environmental protection (again, based on antioxidant) and even as a moisturising active.

Maybe my bias towards liking this ingredient got the better of me of maybe the science speaks for its self.

Answers on a postcard…

Amanda x

Some Liquid Soap Chemistry

April 12, 2020

It’s only when you dive deeply into the science of liquid soap making that you realise how interesting and chemistry-rich every little step of that process is.  I rarely get time to just meander through a personal project as I’m always caught between feeling guilty about the things I still have on my science work ‘to do’ list or feeling out of time due to the ebb and flow of normal life.  Thankfully the Coronaverse has taken a large number of options and choices away from me (while giving me heaps more to deal with – turns out that the one time people do need and listen to chemists is during a pandemic) so spending two days on a liquid soap suddenly became a thing.

I’m sure that most people who will read this will have a basic understanding of soap making.  For those who don’t and by way of a quick summary here’s the science.

Saponification: Turning oil into soap with the help of a chemical called ‘lye’ (short for alkali).


Chemically both vegetable and animal derived oils are triglycerides.  Triglycerides are a combination of one part glycerin and 3 parts fatty acids.  The lye (Sodium Hydroxide mostly for soap bars and Potassium Hydroxide for liquid soaps) can be made into a very high pH solution and added to the oils upon which they start to react chemically to take on a new set of chemistry.

During saponification the triglycerides (which are also known as triesters due to their structure) are broken open by the addition of the lye which cuts through the glycerin/ fatty acid bonds to liberate (free) the fatty acids and glycerin from each other.   The fatty acids quickly combine with the positively charged metal oil from the lye to form what we call a ‘salt’ only these salts are not like the salt you put onto your chips, these salts are bubbly and surface-active and are better known as soaps.  These soaps are anionic (-ve charged).

Meanwhile the glycerin is now left sitting pretty, intact and free.  In this form it is highly water soluble, moisturising and heavy (heavier than water).   It’s worth noting that glycerin is a type of alcohol and is sometimes referred to as Glycerol or spelled Glycerine.  All three are one in the same and are brought to you by saponification.

So when making liquid soap we use Potassium Hydroxide as that produces a softer soap.  Lots of people know that and would repeat that phrase without really thinking any more about it but I can’t help but ask more questions:

  • Potassium soap is softer than what though?
  • By how much is it softer and how do we measure that?
  • Why is this soap softer anyway?

The answers are quite interesting (to me, at least).

I found a paper that gave the Krafft points of different salts of fatty acids.  This was the best paper I could find to answer my question with regards to potassium soap being softer than what?

If I look at the data given for potassium vs sodium soaps, the two most common and most familiar to soap-makers I find that the Krafft Points of Potassium Soaps are much lower than the sodium:

Here’s the data showing the resting (non-changed) Krafft Points of some common soaps:

Potassium Laurate. 10C

Sodium Laurate  25C

Potassium Myristate. 25C

Sodium Myristate 45C

Potassium Palmitate 45C

Sodium Palmitate 60C

Potassium Stearate 55C

Sodium Stearate 70C


Great, but what’s that got to do with liquid soap making, you may ask.

Krafft Point (and it was someones name so don’t spell it Kraft). 

Krafft Point is a feature of ionic surfactants. It is the point (temperature) at which the surfactant becomes useful i.e: where its solubility is such that the surfactant can start forming micelles and display surfactant-like behaviour. Another term for this point is its Critical Micelle Concentration (CMC).

Now that may not sound too interesting at this point but it is interesting if you’ve ever made liquid soap and wondered what on Gods name it’s thinking when it just won’t mix into water after you try to dilute it after making it.

What’s happening there has a lot to do with the soaps Krafft Point and while it seems very simple  based on what I’ve just said above (that the Krafft point is a simple temperature related thing) it gets more interesting when you consider how a soaps Krafft Point can be altered!

Altering a Krafft Point.

Regular salts such as Sodium Chloride, Potassium Chloride and others affect the Krafft Point, depressing it (making it lower) up to a point, above which the surfactant may ‘salt-out’ (a term for when the environment is too salty for the soap and it responds by losing its shit).  Now lowering the Krafft Point is a good thing as it means the soap will be fully soluble at a lower temperature rather than having to be heated.  We want our cosmetic products to be fully functional and in their best shape between the temperatures of around 5 – 45C and while that’s not always strictly possible, it’s something to aim for.  Understanding that for liquid soap,  you can stack the odds in your favour by understanding the Krafft point is powerful stuff.

Glycerin and other alcohols (including sorbitol, propane-diol, hexylene glycol, ethanol etc) improve soap solubility in water, thus reducing its Krafft Point.  I instinctively thought of adding more glycerin to my liquid soap in an attempt to increase its solubility because I did notice that my soap batter seemed to be far too attracted to its self to bother with trying to break the waters hydrogen bonds and make a little hole for its self to sit in.  I felt that the glycerin could ‘soften’ the hold the soap had on its self somewhat and in doing so, create an opportunity for a new relationship to form (between the water and the soap).  It turns out that glycerin interferes with the bonding between the soap molecules thus opening up a gap for water to get in. When concentrated the tails of the soaps form bonds between them (Van der Waals) which require some energy to break. The glycerin improves the changes of bonding happening between the water and soap rather than just within the water and within the soap. However, it turned out that just adding more glycerin was only half of the equation, the whole mixture needed to be re-heated for the real solubility magic to happen.  Glycerin + Heat + more mixing = beautifully solubilised liquid soap.

Upon reading further, the requirement for an extra dose of heat wasn’t surprising as I was right, the energy needed to break the soap-soap and water-water bonds was high enough to make the situation difficult, adding that extra boost of some heat energy lubricated the process enough to make forming soap-water bonds much easier and more attractive.

NOTE ON EXTRA GLYCERIN (or other alcohols for that matter). 

Now there has been some talk of adding glycerin to the lye prior to saponification, apparently it’s quite a well known method to speed things up.  Basically people dissolve the Potassium Hydroxide in Glycerin on a stove top (the lye is not very soluble in the glycerin) and then add that to the oils.  I can see that this works by concentrating the potassium hydroxide and speeding up its attack and if people can handle that, fine.  However, it does look quite a bit more dangerous than adding the hydroxide to water and then adding the glycerin to boost solubility later on.

Some people seem worried that the extra glycerin may be reacting with the lye to produce other chemicals, sometimes toxic things. It is highly unlikely that any further reactions than basic saponification go on during this process, even if a microwave is used to get the liquid soap dilution part finished quickly.  The polymerisation of glycerin into Polyglyceryl esters is possible with just heat, lye and glycerin but it takes 8-14 hours and is typically done at temperatures of around 300C and / or pressures around 60 times greater than we find on earth.  Half the problem with the information on the internet is that there’s a glimmer of truth in it but that someone reading a science paper has mis-understood it or taken a theoretical risk and turned it into a certain threat.  Basically you can add glycerin at any stage you like and be fine, I guess it’s up to you but I feel adding it after is safer and easier to control.

Other ways of influencing Krafft Point. 

Temperature affects the Krafft Point as mentioned above, for ionic soaps it is normal for the soap to become more soluble in high temperatures and less so in the cold – this is why some people’s Castile soap goes cloudy in the winter. You can see from the above examples with different fatty soaps, the temperature at which these things become soluble can vary and in some cases be far too high without intervention to make a practical product.  The soap I made contained around 16%  Potassium Palmitate/ Stearate both of which are not that soluble in water under normal conditions.  So I HAD to play with the Krafft Point to stand a chance of getting my Coconut soap clear and lovely under normal conditions!  It’s that simple.

Concentration of the soap affects the Krafft Point – a soap has to be present at its Critical Micelle Concentration to reach this point, below that it may exist as monomers only, rather than micelles.  Now this isn’t usually a problem in soap making as you are creating a concentrate but it is worthwhile knowing and there’s definitely problems at the other end of the scale too when your liquid soap dilute is made too strong – you’ll end up with floaty bits of a surface hard layer if you exceed the holding capacity of your water.  Remember that the soap is forming micelles and there’s only so much space for them to sit and spread out in, after which point they start to become attracted to the ‘other’ surfaces such as the interface between the air and the top of the product.  If that happens, dilute your soap.

pH affects the Krafft Point too.   Solubility is always affected by everything (it’s an applied, rather than absolute measure) and pH is an important factor of that.  Different oils saponify into different fatty soaps, usually with carbon chains ranging from C12 – C18 but sometimes outside of that on either end.  These individual fatty soaps each have their own solubility parameters and pH ‘sweet spots’.  What changing the pH does is change the degree to which the head (or functional group) of the soap is activated (protonated or deprotonated).  If the pH gets too extreme the soap can lose their heads altogether but within the soaps sensible mid-range,  this property of soap can help you reach an optimal degree of solubility.

But there are multiple fatty soaps in a vegetable soap, which pH do I aim for?

With a blend such as that which we find in liquid soap, there’s usually a ‘majority rules’ pH point where the soaps all sit happily in the mixture.  As this does depend on your particular soap recipe it can vary between makers but the solubility sweet spot is typically between pH 9-11.  One thing I found with my particular recipe is that it settled at a pH of 9 when first made but reached its peak balance point between solubility and mild feeling when adjusted up to pH 10.  Keeping this in mind, it’s pertinent for liquid soapers to keep that pH meter handy at all times as everything you do to your soap during dilution could affect its pH.  You can try and calculate this by looking at your particular oil formula and calculating what your dominant (or most abundant) fatty soap chemistry is then tracing back its happy place pH.  Otherwise just observe the clarity of your soap as you gently raise and lower the pH. Same, Same.

So with that I’ll sign off…

While soap has been widely studied and saponification has been a reaction that humans have undertaken throughout history, it’s still surprisingly hard to piece together the science that helps us answer the ‘why’s’.  I guess that’s part of what keeps it relevant and interesting as both a hobby and a job.  It always excites me to dive into something that seems ‘known’ only to find that we really know next to nothing at all.  Keeps life interesting.

I hope you are well and if, like me, you’ve not been (I got a dose of flu, it really sucked and my lungs are still a bit dodgy, probably not helped by that long summer of bush fire smoke but hey ho, if I’m here for a good time and not a long time so be it) just do your best to enjoy it.

Amanda x

PS: Along my reading travels I found this paper on bush fire retardant foam. Apparently that’s now a potassium soap base due to its high environmental tolerance.  Lots of pink foamy stuff was dropped onto the places around us this summer so it’s good to know that I can whip up a few tonnes of this and keep us safe.



Alcohol is not the only solution Karen!

April 2, 2020

One day, back in 2018,  I sat at home and traced back the qualifications and life experience of the top 29 members of the Australian Federal parliament.  Out of those, 41% hadn’t really had a job outside of politics, 62% were qualified in economics, law and business administration, 21% were women, 1 was a teacher, 1 a farmer and the rest covered a few other professions but guess what?  There were no Scientists.

I’m tired.

I was tired before this pandemic because of bush fires. My lungs already hurt from breathing in the equivalent of 20-30 per day smokes over what should have been our relaxing summer break and before that I was tired because life is hard when its sandwiched between teens and oldies with dementia, bless them.  But never mind, that’s just that and this is just this.  However, the journey I’ve taken to get here, at this point in this pandemic is relevant when it comes to how I’m feeling about Karen.

I’m sure, by now you’ve all heard about Karen.  She’s a middle-aged-white-women, my age and demographic really, who knows everything, always wants to see the manager and has a soft spot for party plan and multi-level-marketing companies.  Maybe she’d enjoy ‘On Becoming A God In Central Florida’ such a great show…

But that’s not all Karen’s got going for her, she’s now also a top virologist,  whizz at reading and interpreting scientific papers and, to top it all off, is a dab hand at formulating and evaluating sanitiser sprays and antimicrobial hand cleaners.  You go girl friend!

Anyway, Karen has been making my life hell and I now want to kill her.  As an aside, there have been a few days when, thanks to my domestic situation at present, I’ve contemplated prison as an option. Not that I would actually kill anyone of course, I can barely speed through the mountains without feeling like I should be on Australia’s most wanted list, but more to just catch a relaxing break, maybe get on with my Masters and even a Doctorate and, let’s face it, I’d probably look good in Orange.  I digress again – keep forgetting to take my ADHD meds which, interestingly enough, don’t work nearly as well if you don’t sleep which makes perfect sense when you think about it.

So Karen, God bless her, has been adding to my general sense of un-zen-ness and dis-ease.

I am not inhumane and do not lack empathy and as such, I appreciate that the challenging times in which we find ourselves have pushed many a good person over the edge.  Like the rest of us Karen is just trying to find some solid and simple truth amongst the chaos, something she can take control of and utilise to keep her family safe.  Anything that challenges that, challenges her and taking on Karen is not something she takes lying down (and I mean nothing sexual by that BTW).

But I have to take Karen on because I’m a chemist and I’ve literally waited my whole life for a big science project, whoops, I mean global pandemic like this to get my teeth stuck into…

As anyone who has read my garbage before knows, I am a huge detail-obsessed nerd with a penchant for applied data and by applied I mean I actually have to live the data.  That doesn’t just mean reading something on a screen or in a book then regurgitating it verbatim or otherwise, it means feeling the chemistry run through my hands or a factory I’m involved in or connected to, walking through the environmental steps and experiencing the good, bad and ugly efficacy the product delivers.  I’m somewhat obsessed with bringing this stuff to life and building a very intimate, very human connection with it, whatever it happens to be. In this case it’s sanitisers.

So Karen has been busting my balls about sanitisers for a few weeks now.  Apparently in her world only 80% ethanol kills CORONA and everything else is just bullshit.  Again, I can understand why she is feeling like that.  Remember above when I mentioned about the Australian Government and the fact that none of them are highly science trained?  Well, they have decided to focus all of their sanitisation information and attention on alcohol-based products. The net result of that being that it makes sense for Karen to draw the conclusion that alcohol is the only solution.  Only those of us who do have a science and especially an industrial chemical, medical or food background know it isn’t.

This first screenshot shows you the list of actives approved for use in sanitisers for general cleaning during this time  in Singapore. I took that picture yesterday.

Below is a screenshot of a brochure published by the EU for cleaning in non-health settings.  The second screenshot highlights the actives that show efficacy against the COVID virus family or against a virus of similar intensity (remember that COVID 19 is very new so there isn’t that much data on how different cleaners kill that exact strain of Coronavirus).

This last section is a link to the USA’s Environmental Protection Agencies list.  On this website there  15 pages to date full of sanitiser products to choose from, covering a wide range of active ingredients for all types of microbe including a tick for those that are likely to be active against emerging viruses like COVID19. What’s particularly interesting about the way this data is presented is that it allows us to see the same active in different product settings. See how Citric Acid is shown just there with a ‘yes’ beside it for COVID19, well on the next couple of lines are products that contain citric that don’t meet that criteria.  This really does go to show that there is a huge danger in hanging so much  weight on what I call an ‘orphan’ active.  What I mean by that is when we detach an active from the detail of how, when and where it is to be applied, we form an incomplete and inaccurate picture of it. That said, it can be a useful place to start, a ball-park of sorts.

The remaining ‘yes’ to emerging viral pathogen claims list of actives includes: Chlorine Dioxide, Quaternium Ammonium, Citric Acid, Ethanol, Other Quats (Benzalkonium Chloride type), Hydrochloric Acid, Hydrogen Peroxide, Peracetic Acid, Silver, Hypochlorous Acid, Isopropyl Alcohol, Phenolic, Sodium Chloride,Sodium dichloro-S-triazinetrione, Sodium Hypochlorite, Thymol (yes, that’s the stuff that’s found in Clove Oil).

So Karen,  just as there are many, many different hairstyles you could select from, there are also many, many sanitiser formulations you could approve for keeping your mother ship clean, fresh and under control.

While alcohol continues to be a very good and very useful solution, it really is a bit silly to tell everyone it’s the only one there is.  That Karen,  is Fake News!

PS: Just in case you are sitting there thinking:  ‘well hang on, aren’t you a cosmetic chemist, not a REAL chemist.  No people, no.  I’m a ‘real’ chemist in the sense that I did a full chemistry degree, then worked in the chemical industry training in cosmetic and HI&I cleaning (household, industry and institutional which means hospital) and only then went on to only focus on cosmetics. Even now I still do my fair share of hard surface cleaning formulations and sanitising sprays so yes, I’m still within my lane albeit the slow one compared to some. 

So the TGA have relaxed the laws on hand sanitiser, how good is that…

March 31, 2020


I’ve been reading, writing, training, selling, answering questions and generally living and breathing hand sanitiser for what seems like months now.  Over the weekend, in a swift change of Australian law, a new category of hand sanitiser was created by the TGA, opening up the field for more manufacturers to come into the market and fill the gap that has been created by COVID19.  This change is good in one way, not in another, I’ll attempt to explain both in my own, non regs-specialist way.

F**k, F**K, F**K.

There you have it.

So, without going into the boring detail which you can read for yourself by following the link above, before this change we had either cosmetic or TGA hand sanitisers. Cosmetic were for the general market – people who wanted to sanitise their work spaces (cosmetic factories, high traffic public areas, homes etc).  Being places where people are generally well and not in imminent danger of succumbing to a microbial attack, these sanitisers were seen as low-risk and regulated as such.  While the formulations that companies made to cater for this market were not necessarily any different to TGA formulations, the burden of material control, factory regulatory framework, material specification,  batch testing and (most visibly) and pack claim scope and proof was generally lower and more general than is the case for therapeutic goods.


The reason for the extra bureaucracy and control over TGA products is that the people using them are generally expected to be weakened/ prone to infection/ already infected or the like, so a tighter ship has to be run, variability between batches and manufacturers has to be reduced.  That’s it.

Because the cosmetic classification of hand and work space sanitisers are for use by healthy populations it makes no sense to make specific anti-viral or anti-bacterial claims for these products.  It is enough to say that a product is broadly anti-microbial or anti-bacterial.  The term ‘anti-viral’ or to single out a particular microorganism and make claims about controlling that is over-the-top for this market and in breach of TGA laws so we can’t do it EVEN IF OUR FORMULATIONS ARE THE SAME AS TGA FORMULATIONS.  You get the picture…

So now, a third category of sanitiser has been made available, a twilight zone category.  This is where the TGA have agreed to allow non-TGA manufacturers to start making a TGA approved formula (it’s actually just the World Health Organisations very basic recommendation, not really an optimised formula but hey, ho, desperate times and all that…)  without having to go through all of the red tape.  But if you are a manufacturer wanting to heed the call and get on with doing this, be aware that you still have to comply with the material specification part of the rigmarole rather than just buying any old crap to put in.  This is, except for alcohol where they have opened up the criteria to allow manufacturers to access drinkable alcohol, the type that breweries are making, to make the sanitiser, that is if the breweries will release any as they too are making sanitiser now it seems (aaaahhhhhhh).

This third category is explained here:

Specific formulations excluded from TGA regulation for the duration of the COVID-19 pandemic

On 28 March 2020, specified hand sanitiser formulations were excluded from TGA regulation, as long as they only contain particular ingredients in particular quantities in the final formulation, and comply with certain manufacturing practices, and advertisement and labelling conditions. Provided that the exact formulation and other requirements are followed, this formulation is permitted for use in both healthcare facilities and consumer use.

This exclusion will facilitate the urgent and continued supply of large volumes of hand sanitisers in Australia.

The formulations are based on advice by the World Health Organization and similar decisions by the US Food and Drug Administration. The final formulation of the hand sanitiser must contain only the following ingredients:

  • EITHER ethanol 80% v/v (pharmacopoeial grade or food standard grade) OR isopropyl alcohol 75% v/v (pharmacopoeial grade) in an aqueous solution;
  • sterile distilled water or boiled cold water;
  • glycerol 1.45% v/v (pharmacopoeial grade);
  • hydrogen peroxide 0.125% v/v (pharmacopoeial grade); and
  • does not contain any other active or inactive ingredients, including colours, fragrances or emollients.

There are strict requirements for labelling of these products. Manufacturers must also test the alcohol concentrations of each batch, manufacture under sanitary conditions and maintain production record-keeping. The legislation enabling production of these sanitisers is the Therapeutic Goods (Excluded Goods – Hand Sanitisers) Determination 2020.

So who will be able to take advantage of this law change?

Ok, so I say ‘take advantage’ in very lose terms, there have been issues with some sections of the cosmetic industry feeling that others are ‘cashing in’ on the desperate need for hand sanitiser and I’m sure that some little buggers are but on the whole, most reputable companies remain reputable during a crisis and just try to do the best they can.  Reputable companies will read the information set out by the government and will go all out to comply with testing requirements, ingredient traceability and quality, batch control, good manufacturing practice and label compliance.   Shit-head companies and people who just think that during a time of crisis, anything goes either won’t read the document, will read it and feel it doesn’t apply to them or will read it and not understand it.  We can’t waste time worrying about that, that’s for the police to sort out.

Make no mistake about it, complying with this new category of hand sanitiser is not a piece of cake and is not something that all people who have a NICNAS permit will be able to achieve. This will really benefit those factories that are already set up to produce this type of product, have a history of doing so, an understanding of chemistry and the ‘why’s’ and ‘wherefores’ of what is being spelled out and are able to do a good job and take some pressure off the supply chain.  In that regard this law change is good.

Where is the law change a bit crap?

Whoever rushed this through didn’t appreciate the nuanced difference between the World Health Organisations presentation of a basic framework formula and industries work to turn that into an optimised applied formula.  As a consequence we are now only able to comply with the TGA’s third category by producing a sub-optimal watery spritz that contains peroxide as well as high strength alcohol and too much glycerin (the TGA clearly didn’t go on to read the WHO’s follow up report on glycerin levels and skin conditioning).

Peroxide is also known as rocket fuel – check this out for my prediction of how your friendly and clueless bucket chemists will be blowing themselves up in the following weeks thanks to hydrogen peroxide fuelled ‘experimentations’.  The last 20 seconds of this video are the best 🙂

In terms of hand sanitiser, the peroxide bit is the bleaching agent or a secondary antimicrobial active within the formula.  Peroxide is very unstable and can easily lead to bottles distorting and blowing off the shelf.  I would not be surprised if people trying to follow this formula don’t blow themselves or at least their bottles off the shelf – this is a big reason why most commercial formulations omit the peroxide part.

It also pays to note that this third category of sanitiser is not thick, has no aroma and is a bit stronger in terms of ethanol than your day-to-day formula which tends to sit at around the 70% Volume/Volume alcohol rather than the 80% mandated here.

So what’s the net result of this change?

Ummmm, I’m not sure as to how many legitimate manufacturers will take up the invitation of making this third category of product but I do think the general relaxation of laws around alcohol (which I was lobbying for) is a good thing as it may just keep some professional sanitiser manufacturers in business due to freeing up the alcohol supply chain somewhat.   I am worried that the way this law has been written could increase the risk of manufacturing accidents and incidents and also could put high strength potable (drinkable) alcohol in the hands of vulnerable people, either in the form of very simple (and therefore drinkable) sanitiser solutions containing deathly levels of alcohol or by way of further encouraging those without adequate training to ‘give it a go’.   On the increased risk of ingestion, one reason manufacturers ‘optimise’ their formulations by adding fragrance and additives is to reduce the potability of the product – most fragrances taste like shite and most accidental ingestions are limited by this factor.  Take away the fragrance component and you have one less barrier to poisoning in my opinion.

These are strange times indeed.  I really hope that this works out for everyone.

Stay safe, don’t play with peroxide and please, just put a fragrance in your sanitiser, preferably one that tastes bad.


A closer look at Alcohol Free Sanitiser Active, Benzalkonium Chloride

March 29, 2020

Benzalkonium Chloride is one of a handful of recognised actives for alcohol-free hand and surface sanitisation, you can look up others by following link 12 (below) which gives a list of EPA approved products based on their actives.

I have a bit of a history with this chemistry. As many long-time readers may know, I started my journey in the chemical industry back in England in 1998.  During the years prior to that and while I was studying chemistry at University the UK and in particular my home county had gone through a round of ‘Mad Cow Disease’ which had put farm biosecurity under the spotlight and more particularly how biosecurity issues can dramatically effect the economy.  Fast forward to 2001 and I was well and truly up and running in my career.  I was managing a product portfolio that included quaternary chemistry for the company I worked for, the quats were supplied by a company called Akzo Nobel and I’d spent some time at their factory learning about how they work, what they do and how they are used.   This all became very useful when another biosecurity issue hit the UK in the form of Hand Foot and Mouth Disease, first detected in pigs.   The long and the short of it was that I ended up seeing a huge upturn in demand for this chemistry as government legislation mandated the use of disinfectant troughs at all farm gates and much stricter control over animal and farm machinery / stock transportation.  The economic, environmental and human impact of that virus fascinated me back then in the same way that Covid 19 has captured our attention now.  Quat chemistry is very interesting and while it does have some down-sides, when used properly it’s a very useful way to get the upper hand on some nasty little microbes.

Let’s take a closer look…

Common applications for Benzalkonium Chloride:

  • Preservative in Medicinal products such as ophthalmic, nasal, inhalation and lozenge preparations.
  • Anti-microbial additive and preservative for cosmetics, wet wipes, hand and surface sanitisers.
  • Biocide in swimming pool chemicals
  • Cationic Surfactant


Unpicking the chemistry – what a name tells us.



A chemical that has a benzene ring structure in its chemistry.


Benzene rings are, as the name suggests, circular molecules containing 6 carbons and 6 hydrogens.  Molecules that contain benzene rings are also classified as aromatic and many exist naturally in essential oils:


Benzyl Alcohol: Tolu Balsam, Benzoin, Violet Leaf Absolute, Jasmine Sambac


Bisabolol: The main skin soothing active in Chamomile oil, also found in Sandalwood.


Limonene:  Sweet Orange, Grapefruit, Lemon, Mandarin, Lie and Caraway.  Commonly used in cleaning products for its solvency powers.


Phenethyl Alcohol: Also known as Rose Alcohol due to it being a major component in Rose Absolute. Also found in Champaca and Jasmine.



This is shorthand for Aklyl which is a name given for a family of chemicals that are made up of carbon-hydrogen bonds.  Methane is the simplest alkane.  So Benzalkonium Chloride has a carbon-hydrogen chain coming off its benzene ring structure.  In this case the Alkyl chain is between C8-C18 long, these chain lengths are typical of what we find in natural fats or triglycerides.



This is the cationic bit – the bit with the positive charge.


A common ‘onium’ ion is Ammonium, NH4+ ,  Ammonium is typically converted to urea in excreted by humans as Urea, found in Urine.   Urea is also a well-known and much used active in medicinal skincare for barrier repair, anti-itch and skin soothing.


Synthetic Onium molecules such as Benzalkonium Chloride fit into another family called Quaternary ammonium cations or QUATS for short.  Quats share similarities in their chemistry to natural oniums (which are also antimicrobial) but they are typically much stronger in their antimicrobial efficacy due to the way the ammonium ion has been modified so as to have a permanent positive charge.


In a synthetic or man-made quat, the ammonium ion is modified by replacing the four hydrogens with carbon chain (or Alk – Alkyl) groups. In Benzalkonium Chloride, two hydrogens are replaced by methyl groups (CH3) and the third is replaced by a carbon chain that is between 8-18 carbons long.



Because the Nitrogen left over from the ammonium salt has a positive charge it can attract a negative Counter-ion to its self.  In the case of Benzalkonium Chloride that counter-ion is chloride, Cl.


The addition of the chloride ion means the finished molecule is stable and qualifies as a salt, another classification of molecule based on its functional group chemistry.   A salt is formed when an acid (Ammonium salt or, in this case quaternium salt) reacts with a base (Chloride) to form a new molecule.


The Chloride ion is most commonly found in cosmetics as common salt – Sodium Chloride.


Putting it all together we get Benzalkonium Chloride:


Unpicking Origin.  Does this chemistry exist in nature?

While the component parts of Benzalkonium Chloride do exist in nature, the way they have been assembled to form this molecule does not occur naturally.    That said, quaternium chemistry is found in nature and molecules with this chemistry perform several metabolic roles within our bodies.  So, chemists didn’t invent quat chemistry, nature did, chemists just modified the look and feel or it, employing it to do slightly different jobs.


How does Benzalkonium Chloride kill microbes?

Benzalkonium Chloride qualifies as a broad-spectrum antimicrobial.  It works by disrupting the membranes of microbes thus weakening and eventually killing them.   Because the action of Benzalkonium Chloride kills microbes, the ingredient is called a Biocide.  In cosmetic science we use ingredients like this as both actives (antimicrobials) and preservatives.  In the case of preservatives, they can be microbiocidal (biocides) or micro biostatic with biocidal molecules generally being thought of as ‘harsher’, stronger or more effective.   While biocidal preservatives are still used in cosmetics, there is a strong trend towards micro-biostatic technology as we learn more about topics such as antibiotic resistance, the skins microbiome and the environmental impacts of biocides.


Are Biocidal actives such as Benzalkonium Chloride bad?

There are lots of pathogenic microbes that require a microbiocidal approach to their management, especially in situations where human health is under attack.  Antibiotics could be classed as biocides and it is here where we see a potential problem when biocides are used indiscriminately.

Antibiotic resistance is a very real threat in our modern world due, to a large degree to our over-zealous and sometimes indiscriminate use of biocides in day-to-day life.  Over the last few years groups such as the FDA in the USA have restricted the use of biocides in common every-day products such as hand soaps due to evidence showing no additional benefit but plenty of potential risk.


When added to soap, ingredients such as benzalkonium chloride do little to improve the antimicrobial efficacy of the product but can add to the overall release of biocide into the environment.   While the action of Benzalkonium Chloride and other biocides is broad-spectrum, these molecules don’t kill everything and what’s more, over time, when exposed to sub-critical doses (non-lethal doses), some microbes can find ways to overcome the threat – build resistance.   This resistance creates microbes such as MRSA (Methicillin-Resistant Staphylococcus Aureus).


While it is tempting to then consider that all biocides are bad and should not be used, it is more accurate at this time to adopt the approach that it is the over-use or indiscriminate application of biocides that is causing the problem rather than their use per se.  Biocides have their place in helping us keep ourselves and our environments safe, clean and sterile but they are should be used with caution and generally only for specific purposes and time frames.


What happens to Benzalkonium Chloride when it gets into the environment?


Being biocidal, this chemical needs to be managed carefully in its concentrated form and should not be released into the environment as is due to its ability to affect natural microbial ecosystems such as soil ecology and water ways.  However, when benzalkonium chloride enters the environment under normal use conditions it will biodegrade and has a low potential for bioaccumulation both in waterways and soil.  Water treatment plants are able to remove this chemical from waste-water and collect it in sediment for further treating or remediation.   So, while it is reasonable to exercise caution with this chemical, it is not the case that this will cause long-term environmental disruption if used sensibly.  As mentioned before, the issues come with wide-spread persistent or indiscriminate use.


It is worth mentioning that all biocidal products have been under review in light of the reality of antibiotic resistance.  In Europe back in 1998, the Biocidal Products Directive initiative was developed and since then several pieces of legislation have been developed, some biocides have been discontinued and others have been more thoroughly investigated to fill any data gaps we have.  Initiatives like this enable the chemical industry to make continued progress on finding ways to reduce the threats that pathogenic microbes pose while not increasing the risks elsewhere.  Since the late 1990’s, the chemical industry has taken a ‘cradle-to-grave’ rather than a discrete (and often detached) problem solving approach to new and existing product (and chemical) development.  As with all things scientific, this is a journey rather than a destination so it is likely that as we know more and develop further more old technology will be replaced as more holistically beneficial chemistry becomes commercially viable and available.


Is Benzalkonium Chloride safe?

As with all biocidal chemicals, benzalkonium chloride should be used with caution due to its potential to add to antibiotic resistance when used indiscriminately and its potential to trigger contact dermatitis in susceptible people, especially when used excessively or when products containing high doses of the active come in frequent contact with the skin.  That said, there has been much research into how this active can be formulated for maximum efficacy with minimum risk.  In terms of sanitisation, effective formulations can be made using less than 0.2% of this on a per-actives basis.   While Benzalkonium Chloride is highly toxic as a neat chemical, when formulated into a typical sanitiser spray, foam or gel, the resulting product often presents a much lower overall toxicity than a formula containing 70% alcohol.


There are several advantages that Benzalkonium Chloride has over alcohol in sanitising solutions including:

  • Lower cost on a per-formula basis,
  • Non-flammable
  • Lower applied toxicity
  • Non-Sting on application.

In addition, due to the cationic nature of Benzalkonium Chloride, it adheres well to skin and surfaces.  This feature can mean that sanitisers containing Benzalkonium Chloride provide much longer-lasting protection and coverage than alcohol-based sanitisers can achieve.


In summary, Benzalkonium Chloride has a lot to offer in terms of keeping us and our environments sanitised but too much of a good thing turns bad.


So, is a product with Benzalkonium Chloride right for me?


Benzalkonium Chloride based sanitiser sprays, gels and foams should definitely be used with caution and should probably not be used as an every-day product by most people/ businesses, all of the time.  However, during times of increased risk or where excellent hygiene is essential to the safe running of a business, sanitisers based on this can be a very useful, highly effective, affordable and convenient step in your hygiene protocol.    As to whether these products are safer than alcohol-based sanitisers, as discussed here, you could say both yes and no to that.  A risk-benefit analysis of your particular situation will help determine the answer.


Background Reading

 1). Demonstrating the persistent antibacterial efficacy of a hand sanitizer containing benzalkonium chloride on human skin at 1, 2, and 4 hours after application
2)    Benzalkonium Chlorides: Uses, Regulatory Status, and Microbial Resistance
3)    Ecotoxicity of disinfectant benzalkonium chloride and its mixture with antineoplastic drug 5-fluorouracil towards alga Pseudokirchneriella subcapitata
4)    Benzalkyl quaternary ammonium surfactants: Environment tier II assessment
5)  The European Union’s Biocidal Product Directive.
6)  Fate of Benzalkonium Chlorides in Natural Environment and Treatment Processes
7)    Quaternary Ammonium Compounds: An Antimicrobial Mainstay and Platform for Innovation to Address Bacterial Resistance
8)  Benzalkonium chloride used as an excipient
9) Granular parakeratosis induced by benzalkonium chloride exposure from laundry rinse aids.
10) Is the irritant benzalkonium chloride a contact allergen?
11) Topical antiseptic products. Hand Sanitisers and Antibacterial Soaps.
12) EPA List N. Disinfectants for use against SARS-COV-2

13) Clinical biosecurity news. BSE – Mad Cow Disease.