This week I’ve mostly been reading about armpits…

I wrote a post the other week debunking the myth (well, attempting to) that our armpits ‘detox’ when we change deodorants and since then I’ve been itching to know more about what turns out to be a truly fascinating part of our anatomy.  I thought you guys might like to join in the fun too so I’m going to write about it all here.

Firstly I was introduced to a chap called ‘Dr Armpit‘ by one of my readers (thank you) and I was immediately drawn to his wall of agar plates article, so fascinating.   Now if anyone out there in reader land wants to buy me a present, I’d love a ticket to go see this chap in his lab as there is just so much to talk about and learn.  Seriously, please fund me :). Anyway, what I like about what Dr Armpit has done is that he is clearly a great scientist but his work is instantly understandable, relatable and engaging. I don’t always have that response to the researchers that I read.   So, what does he say?

What makes us smelly?

Dr Armpit has done a fair bit of research into what makes us smelly and it turns out that a few other people have done this too.  Now it has been known for a longish time (I know, not very specific but this is a blog rather than an academic journal) that bacteria play a part in producing body odour – sweat doesn’t smell until it is broken down by something.  However, it is only relatively recently that we have started to welcome and nurture our microbiomes and see what joy they can bring us.  Turns out this joy applies to the armpit area too.  So not only does Dr Armpit give us a good look at the microbes that grow on different people’s armpits thanks to his wall of agar plates, he also goes a long way into explaining which microbes cause the stink and how our own personal hygiene habits impact on them.  As a product developer this is absolutely fascinating to me as I have been pondering on how I can make an antibacterial deodorant without risking wiping out the ‘good’ bacteria or referencing the bad.  It turns out that my fears seem to have been valid as there is truth in the idea that some deodorants can alter our micro biome and allow an opportunity for less pleasant microbes to flourish – our habits change our micro biome.

Formulating for our micro biome.

Understanding that our microbiome is affected by our choice is deodorants isn’t the same as knowing how to fix it and I have to say that I’m not 100% there yet with a solution in my mind and I’m not alone.  The truth of the matter is that scientific understanding of the complexity of our micro biome is still under-developed and while we can measure what is there now and what is there later (when later comes around) we (scientists) are not yet able to accurately predict what results our actions may have and why.  This is partly to do with the fact that armpit micro biomes are not just affected by deodorant use, they are affected by our genetics, diet, environment, clothing choices, health and emotional states.   Now you might be thinking ‘well, of course you know that something is working because the smell goes away’ and to a point that is true. However, the why, how’s and what (are the longer-term implications) are still to be answered as we strive for better products which give better results.

What we do know is that gram positive bacteria of the Corynebacterium species are the type most likely to cause a stink, that armpit bacteria populations have a fairly low diversity compared to other areas of the body and that men tend to have more of these present than women (who are dominated by Staphylococci).  Now that’s interesting too isn’t it?

Why would men and women have different armpit microbes?

This is a question that popped up into my head.  Dr Armpit suggests it is because of a difference in skin thickness with mens skin being thicker than women.  That may well be a contributing factor but I also feel it could have something to do with armpit hair maybe.  This study does mention that the test panel they used had to refrain from shaving their armpits for a couple of weeks before the test and during the test period. That would mean that most participants would have some armpit hair. However, I can’t see that hair has been discussed as a factor in these experiments really so I’m still curious about that. The question in my head is whether the surface area / air entrapment area under the armpit increase that you would get with a bush of hair may act as a nutrient source for microbes that could either a) feed the good bacteria and help them thrive or b) feed the bad bacteria and encourage their growth or c) feed all bacteria and lead to more bacteria being present of which some is the smell-inducing type or d) the lack of hair removal helps maintain a more natural barrier functioning that helps keep the armpit microbiota in check or e) hair is irrelevant.   I’d like to know more about that, especially as hair removal in women literally became fashionable in modern western times thanks to deodorants and that it is now becoming OK for western women to choose if they want to maintain or remove their armpit hair – woohoo for us!  I just don’t want people to feed any misconceptions about hair under there really…

Anyway, there is so much more to learn including this bit on chemistry:

Chemically speaking sweat from our eccrine glands (of which we have around 200 per square CM of skin) is around 99% water!  The other 1% contains bicarb, potassium, chloride, sodium, amino acids, urea, magnesium and a few other bits.  These trace minerals can be quite good for the skin, in fact, as a cosmetic chemist I’m often putting this type of thing back into a water phase to make the water better.  It makes sense that something we generate ourselves as part of our homeostasis would be ‘good’ for us don’t you think?  That rather than see our sweat as dirty, it is actually our bodies pumping out some freshly squeezed made-with-love spritzer for us.  Aaahhh bless.

But eccrine gland are not the only ones. We also have apocrine and apocrine glands (which people are still a bit confused about) under there.  Apocrine glands are attached to hair follicles whereas eccrine glands are not.

Apocrine glands are responsible for our emotional sweating and while the sweat is still quite watery it also contains some fatty bits.  This may be because it gets mixed with sebum on its way out of the hair follicle or may not. I don’t know at this point in time.  While we have eccrine glands all over us, our apocrine glands are concentrated in our genital, armpit and breast areas. Grossed out by that?  Well we also have these little suckers on our eyelids, up our nose and in our ears – weird!

Some say that our apocrine glands secrete pheromones and it is our pheromones that make us fall in love.  Now I tend to believe that as I do like to remember that we are all animals after all but it can sometimes be hard to find any robust science on this type of thing.   But then I found this.  That link is to PUBMED by the way so you may not be able to view the full study but if you go to Deep Dyvve you can find it there to download for a small fee.  Ok so the paper I just put a link to talks about this:

Body Odours affect our emotions.

Sure, we’ve all sat next to some smelly bar-stuard that forgot to wear deodorant and that’s brought up some emotions in us but I’m not talking about that.  I’m talking about something more subtle.

The paper above found that we respond emotionally to other people’s emotional sweat.  So when your best friend Sally is having a bit of a meltdown because she’s got an exam in the morning you may start to feel anxious too, not because of her behaviour but because of her smell.

Apparently our emotional sweat odour was able to induce changes in heart rate, sweating rate and how test subjects felt which is probably not surprising as it is definitely the case that most animals pick up on our non-verbal cues very quickly. However, it is totally worth thinking through, especially if we are working in trauma settings.  We want our body odours to be calm and calming so that the unspoken environment is one that spreads joy rather than fear.  Now there’s an opportunity.

And another thing. Alcohol and Caffeine.

So probably one chemical you don’t want to put into your deodorant or antiperspirants is caffeine.  Caffeine increases the body temperature, sweating volume, number of active sweat glands and sweating sensitivity.   None of that is a good thing when you have a body odour issue.  I hadn’t really thought of that before but it is very useful for deodorant brand marketers to consider.  In the days of insta-goodness make sure you aren’t promoting sweating with your deodorant.

Then there is alcohol.  Now it turns out that this is a double-edged sword (good and bad).  Alcohol changes blood pressure, flushes the skin and increases sweating because of that and that can make the old deodorant work harder.  However, pop a bit of alcohol into your deodorant and you have a faster drying, anti-microbial solution.  Maybe the key is keeping the alcohol on the skin rather than under it.

So there you go.  There’s a whole lot more interesting things that I’m discovering about armpits as I go off on this tangent in order to make better products but that will do you for now.  The only other thing I want to tell you about is why I do this.  As a cosmetic chemist it would be all too easy to just copy someone else work and create deodorants for people who are exactly like someone else already has.  Now you might say ‘and yes, that would be smart too as it saves time and if the deodorant works, why wouldn’t you’.  That is a good point but as you can see from the above,  there are many angles that we are uncovering and investigating with the armpit area and I want to be sure to make the best products that I can make, not just a cheap knock-off of something else.  As a formulating chemist I do quite often see products that work but I don’t know how or for how long they will work – brand longevity is an issue and you don’t want customers to only stick around while it is a novelty. Or I see products that are popular/ trendy but that don’t really work.  I feel it is my duty to add value to brand owners by working out the why, how’s and what’s of a product. After all, if I don’t do that, all I am is just a glorified lab technician who puts your wish list into a generic base and then rides off into the sunset not giving a shit about what I’ve done to your micro biome over the long-term – not my problem.  Now that’s just not me, that’s not what I signed up for when I became a chemist and I hope that’s not what you want either.

The bottom line is that our armpits are actually quite fascinating and deserve a heck of a lot more attention than I’ve previously given them.

I hope that has been interesting for you and I look forward to sharing some more news from the nerd factory with you later.

Amanda x