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An Honest Mistake. When Zinc Based Sunscreens Go Wrong.

August 9, 2015

I awoke this morning to a story on Forbes entitled ‘The Failure of Jessica Alba’s Honest Company Sunscreen Explained’ and immediately wanted to find out more as sunscreen failure has to be a brand owner (and formulators) worst nightmare.  After looking over some of the feedback on Amazon, especially comments that have come back in over this summer (Northern Hemisphere) I have to say there is no getting away from the fact that this product is causing some problems, even though official comment from the company states that complaints were running at less than 1% of sales.  Apparently the sunscreen was re-formulated for this season after people feeling it was too greasy before so this may well be the first summer for the new, ‘improved’ formula which now contains Zinc Oxide (non nano apparently) at 9.3% down from 20% in the old formula.

The original article I read on Forbes can be accessed here. It gives a reasonable review of the situation but does miss a couple of broader issues out and gets a couple of bits wrong, bits I want to discuss here.

But first I thought I’d also draw your attention to a pretty good article explaining the reliability of AMAZON reviews. Apparently there are people who review products they haven’t even tried just because they don’t like the ‘sound’ of them.  Worth keeping in mind…..

The Sunscreen.

This is a zinc-only SPF 30

ACTIVE INGREDIENT:

Non-Nano Zinc Oxide 9.3%

INACTIVE INGREDIENTS:

Beeswax*, Butyloctyl Salicylate, Butyrospermum Parkii (Shea) Butter*, Calendula Officinalis Flower Extract*, Chamomilla Recutita (Matricaria) Flower Extract*, Cocos Nucifera (Coconut) Oil, Helianthus Annuus (Sunflower) Seed Oil, Hydrogenated Vegetable Oil, Jojoba Esters, Methyl Dihydroabietate, Olea Europaea (Olive) Fruit Oil*, Prunus Armeniaca (Apricot) Kernel Oil, Silica, Simmondsia Chinensis (Jojoba) Seed Oil*, Tocopherol

Claims (Direct from the brand website)

  • Naturally derived, unscented, broad-spectrum (UVA and UVB) SPF mineral sunscreen – everything you need, nothing you don’t
  • Easy to apply, non-greasy, non-whitening (non-nano!) zinc oxide sunscreen provides safe, effective sun protection for the entire family
  • Zinc oxide is the ONLY active sunscreen ingredient – NO synthetic chemical sunscreens
  • Water resistant – tested effective for up to 80 minutes
  • Shake well before use!
  • Hypoallergenic • Non-Nano • Mineral-Based • Biodegradable • Reef-Friendly • Water Resistant (80 minutes) • pH Balanced

About the formula.

The first thing that strikes me here is the low-level of zinc oxide.  Zinc Oxide is a great sunscreen active but it is very hard to get more than 1.5 SPF units per 1% Zinc out of it and to be honest, even that is pushing it.  Sunscreen zinc can be anything from say 10 nanometers in diameter (a true nano particle) up to 200 nanometers.

Zinc in the 10-100 nanometers diameter range goes on clear and gives you the highest SPF per % rating.  This formula claims to have 9.3% zinc and an SPF of 30.  That means that each % of zinc is giving over 3 SPF units which is pretty damn amazing.  I’ll not say ‘impossible’ as I am happy to admit to not knowing everything but without a second filter to work synergistically with this SPF performance, especially for a filter that claims NON-NANO is nothing short of miraculous.

Zinc that sits between 101-200 nanometers is what we call MICRONISED zinc. This is still clear and is NON-NANO.  It typically gives an SPF of between 0.8-1.2 SPF units per %.  9.3% Zinc would be expected to achieve an SPF of between 7.44-11.16 SPF under normal circumstances.

So what is going on?

Supporting Cast Additives. 

Well sunscreens don’t just rely on filters alone, filter efficacy can be boosted in many ways including the use of film formers (to boost surface adhesion),  great pigment wetting agents (of the type of technology we use in lipsticks to get a better colour payoff), the use of anti-inflammatory agents (to slow down our reddening response. The use of these is somewhat controversial as it may give an artificially high SPF) and/or the use of other ingredients that have some UV protective features but aren’t listed as sunscreen actives (Raspberry seed oil, seabuckthorn, shea butter etc. Although these typically only have a very small impact on an SPF test).

I can see a couple of ingredients in this formula that would help to boost SPF performance in one or more of the ways described above.

In-Process-Nanofication.

OK so I made that term up BUT one thing that is possible is for a manufacturer to use non-nano zinc in their recipe but process it in a way that de-aggregates it by using roll mills and other highly energetic processes to pound it down and therefore increase its potential to give a higher SPF.  Here is one article demonstrating that this is possible.  Now I’m thinking that if this was going on the finished formula SHOULD be marketed as containing nanoparticles but it would be difficult to know that this was going on unless the manufacturer of the formula disclosed it.  It is highly unlikely that the Honest range has its own factory and even knows how its products are made.

Other things in the formula of note.

I did notice that the second ingredient after beeswax is Butyloctyl Salicylate – a synthetic ester of salicylic acid that is used to help disperse pigments (in colour cosmetics and sunscreens).  It makes sense to have this in here and this ingredient may well be one that boosts the SPF but I did wonder how that got to pass the ‘Honest’ definition of ‘naturally derived’, especially as it would be present in a decent amount being the second ingredient in (outside of the declared active). In addition to that chemically this ingredient is in the same family as the ‘chemical’ sunscreen actives that are used in ‘regular’ sunscreens which makes it’s use all the more intriguing.

I also found the ingredient Methyl Dihydroabietate interesting – it is spelled incorrectly on the website, the Dihydro should be Dehydro but as I’m rubbish at spelling I’ll not harp on about that.   This is another highly functional emollient or spreading agent but this time it is naturally derived.  These di-terpenes can come from pine resin or from Algae (very exciting, I love Algae chemistry).  See here for more info. 

But really that’s it with the formula.  It’s all oil based so there is no emulsifier, no preservative and nothing else weird to note. I would expect this to feel relatively heavy and greasy but again, that isn’t unusual for an oil based zinc product and that doesn’t usually stop die-hard zinc fans.  The silica in the formula would most likely have to be labelled as nano should this formula get into Europe but that’s another story……

Other things I picked up on after reading the  Forbes article.

  • 80 minutes water resistance.  This may be so in the test but I wouldn’t be putting that on the packet as people with very sensitive skin probably won’t make it that long in a real life environment.  It is always safer to tell customers to over-apply a product than to rely on the best case lab scenario in your marketing.
  • Shake the bottle claims are not allowed for Australian sunscreens but they are allowed in other countries.  The ‘shake before use’ claim works best for ultra-low viscosity products that contain a ball within the pack to help agitate the fluid and re-combine any that has split.  I can’t imagine that this product has a low enough viscosity to make this a possibility given its beeswax, silica and shea butter. Plus there is hydrogenated oil in there to thicken it.  However, I could be wrong as I haven’t seen it.  The reason we can’t have ‘shake’ SPF products here is because they are un-reliable.
  • I tend to agree with the comments from Billy J. Gurley in as much as it looks like the zinc could have settled.   Sunscreen products need to have their SPF tested in a third-party lab before going on the market.  However, it is possible to make a sample, get it tested, have it pass and then place the product onto the market without doing stability testing. In fact, here in Australia the TGA allow you to run your stability testing parallel to your launch – so it doesn’t have to be completed before hand –  as long as should anything go wrong in testing you inform the TGA and pull the product. I’m not sure on how it works in the USA.   A sensible protocol for SPF products is to test SPF after an initial 3 month accelerated stability (equivalent to one year real-time) then re-test the product again in the middle and end of the shelf life and compare results.  Assays of active can also be taken during the shelf life to make sure your sunscreen active is still present evenly throughout the product.  It is entirely possible that this sort of testing hasn’t been done as completely as it could have been and in the final consumer packaging as the above protocol isn’t a legal requirement and different companies take different views of it all.  It is also possible that it has been tested thoroughly and that the current problems are batch specific but either way it needs reviewing.

In Summing up.

I have said it before and will say it again, Zinc based sunscreens are not easy to get right no matter how much money you have to throw at them.  Not only that but the instructions of how to use a sunscreen product must also be crystal clear and not downplay the risks of over-exposure to sun nor up-state the efficacy of a product.

I hope this situation gets resolved soon as it is clear to me that people want honest, simple products but more than that, they need them to work.

Amanda x

23 Comments leave one →
  1. James Donald permalink
    August 31, 2015 7:21 am

    Interesting article. Thanks for your insight. I keep thinking there must be a lot of technology put in these sunscreens. I use a product by Skinceuticals called Physical Fusion UV Defense SPf 50. It has just 6% Zno and 5% TiO2. Out of that they can manage to not only get an Spf of 50, but claim ‘broad spectrum’. As we know, you’re not going to pass the critical wavelength test unless your UVA protection scales to your UVB protection. Any thoughts?

    Here are the ingredients:

    5% Zinc Oxide, 6% Titanium Dioxide. Water, Dimethicone, Isododecane, C12-15 Alkyl Benzoate, Undecane, Triethylhexanoin, Isohexadecane, Nylon-12, Capylyl Methicone, Butyloctyl Salicylate, Phencythl Benzoate, Styrene/acrylates Copolymer, Silica, Tridecane, Dicapylyl, Carbonate, Dicapylyl Ether, Talc, Dimethicone/PEG-10-15 Crosspolymer, Aluminum Stearate, Pentylene Glycol, Peg-9 Polydeimthcylsiloxyethnyld Iethicone, Alumina, Polyhyroxystearaic Acid, Phenoxyethanol, Magnesium Sulfate, Capylyl Glycol, Iron Oxides, PEG-8 Laurate, Disteradimonium Hectorite, Triethoxycapylylsilane, Tocopherol, Propylenen Carbonate, Artemia Extract, Benzoic Acid, C9-15 Flouroalcohol Phosphate, Peg-9, D46941/2.

    • RealizeBeautyEd permalink*
      August 31, 2015 11:58 am

      Hi there James,
      While I can’t justify a particular brand what I can do is give you a bit more insight into what might be happening here.

      An SPF is more than just the filters.
      SPF can be low when you have 25% filter
      Or high with just 11% as above.

      In general terms you might be expected to get an SPF of anywhere from 1-1.5 units per percent of zinc and around 2 per unit of titanium dioxide. This would give the above formula an estimated SPF of 19 on paper so clearly something else is going on.

      The particle size of the zinc and titanium plus their coating can influence SPF, spectrum and skin coverage. Both titanium dioxide and zinc oxide can be manufactured to meet broad spectrum requirements.

      In other ‘news’ the formula above contains film forming ingredients that help spread the product across the skin evenly. This can have a dramatic boosting effect on the formula.

      The formula also contains ingredients to help wet the pigment and encourage it to form a fine rather than thick coating across the skin.

      Further, the formula contains other ingredients that can deflect the suns rays but that aren’t classified as SPF filters in the way that zinc and titanium or the ethyl hexyl methoxycinnamate are. This really helps.

      Lastly the formulator can make the product ultra-light feeling on the skin so that people are happy to pile lots on. This can also help the product to achieve the maximum SPF under ‘real’ circumstances although this is less of an issue in lab testing as the testing works on a set dose format.

      So I hope that helps. This is a technically brilliant formula but isn’t the kind of formula you could put together if you wanted an organic or natural certification.

      • James permalink
        August 31, 2015 5:18 pm

        Thank you for your insight! Appreciate the fast and thorough apply. It’s so interesting.

      • RealizeBeautyEd permalink*
        August 31, 2015 11:58 pm

        It’s all good James 🙂

  2. Yohan permalink
    August 2, 2016 6:45 pm

    Nice review! A few comments:

    The honest company sunscreen lists its ingredients alphabetically as it can choose to do with OTC drug formulas – not really a honest way to do things, Skinceuticals lists theirs by concentration.

    Silica could be used to enhance light scattering, mica is also used this way, increasing the SPF/ %pigment.

    Methyl Dihydroabietate is there to help pigment dispersion and waterproofing, sold under the brand name Meristant from Essential Ingredients.

    Butyloctyl Salicylate straight up absorbs UV, basically chemical sunscreen that’s not approved by the FDA as far as I know.

    As you mention, with US SPF testing, what’s measured is redness on a panel of 10 people after being exposed to simulated sunlight with the sunscreen applied. Anti-inflammatory compounds can then be used to reduce redness and increase SPF, without reducing DNA damage and actual sun protection. Neutrogena does this to get a SPF60 claim for a 10% mineral based formula.

    Kobo published an interesting whitepaper on SPF boosting here: http://www.koboproductsinc.com/Downloads/Practical-tools-for-boosting-sunscreen-efficacy.pdf

    • RealizeBeautyEd permalink*
      August 2, 2016 7:01 pm

      Hi Yohan,
      Thanks for your contribution.
      I’m not a big fan of anti-inflammatories being used to push SPF up as that implies that inflammation is happening (the skin has had too much sun) and is being artificially suppressed whilst allowing the exposure to still occur (people don’t get the normal biological cues that they are in trouble). I’ve been involved with this kind of technology for a number of years but feel very uneasy about it until we can prove that if there is no inflammation, there is no risk. I am not comfortable that is the case.
      I’ve used the Kobo products myself and the silica to do the same job, they are indeed helpful.

  3. Yohan permalink
    August 2, 2016 6:46 pm

    Nice review! A few comments:

    The honest company sunscreen lists its ingredients alphabetically as it can choose to do with OTC drug formulas – not really a honest way to do things, Skinceuticals lists theirs by concentration.

    Silica could be used to enhance light scattering, mica is also used this way, increasing the SPF/ %pigment.

    Methyl Dihydroabietate is there to help pigment dispersion and waterproofing, sold under the brand name Meristant from Essential Ingredients.

    Butyloctyl Salicylate straight up absorbs UV, basically chemical sunscreen that’s not approved by the FDA as far as I know.

    As you mention, with US SPF testing, what’s measured is redness on a panel of 10 people after being exposed to simulated sunlight with the sunscreen applied. Anti-inflammatory compounds can then be used to reduce redness and increase SPF, without reducing DNA damage and actual sun protection. Neutrogena does this to get a SPF60 claim for a 10% mineral based formula.

    Kobo published an interesting whitepaper on SPF boosting here: http://www.koboproductsinc.com/Downloads/Practical-tools-for-boosting-sunscreen-efficacy.pdf

  4. Cybel permalink
    May 28, 2020 6:30 pm

    May I ask where did you get your statistic of “Zinc Oxide is a great sunscreen active but it is very hard to get more than 1.5 SPF units per 1% Zinc out of it and to be honest, even that is pushing it. ” from?
    What about the SPF units per 1% of other physical sunscreen ingredients like Titanium dioxide?
    Or SPF units of chemical sunscreen ingredients like octinoxate and oxybenzone?

    • RealizeBeautyEd permalink*
      May 28, 2020 8:44 pm

      The figures I quoted are well known industry standards for inorganic sunscreen agents, it’s not the same for organics which are more efficient but irrelevant if a client wants a zinc only sunscreen. You can achieve a higher SPF per % input with zinc but mostly with nanoparticles or finely micronized zinc. Again these aren’t applicable for those looking for an organic sunscreen or something nano free.

  5. Peanut permalink
    November 15, 2020 9:57 pm

    Is it true that uncoated zinc oxide degrades avobenzone???

  6. November 16, 2020 12:59 am

    Hi Amanda!

    Love this fact sheet, thank you!

    I have narrowed down my most reef safe sunscreens after hours and hours of research. I’ve noticed a couple of them have Butyloctyl Salicylate in them. I am so so confused as the other ingredients within them don’t seem to be harmful to the environment. Do you think if they have this ingredient they aren’t reef friendly? Or is it only if they are mixed with other known harmful reef chemical ingredients. There is such little info on it individually and I just can’t decide 😦

    • RealizeBeautyEd permalink*
      January 12, 2021 10:28 am

      This is a salicylic acid derivative. The FDA and EU safety information is here: https://cosmeticsinfo.org/ingredient/butyloctyl-salicylate
      An MSDS for the material is here: https://hallstar-sds.thewercs.com/private/document.aspx?PRD=2231~~PDF~~MTR~~AGHX~~EN~~2015-09-09%2015:50:13~~HALLBRITE%C2%AE%20BHB~~. This could be present as a preservative or active depending on where the products are made and sold. In terms of environmental impact the MSDS advises against releasing into waterways but that’s true of most neat chemicals. The actual toxicity for the organisms tested seems low enough for it not to be a source of concern when part of normal use. Salicylic acid is a naturally derived chemical with low water solubility. I’m not sure how that goes with reefs or if anyone has tested it but based on the above evidence there is nothing that stands out immediately other than the fact that it could be more environmentally persistent (non-biodegradable).

  7. Peanut permalink
    November 16, 2020 12:46 pm

    All chemical sunscreens sting my eyes so I fixed this issue by using zinc oxide sunscreen around my eyes then chemical sunscreen for the rest of my face. But I’ve read online (don’t know if it’s true) that uncoated zinc oxide can degrade avobenzone which is in my chemical sunscreen.

    • RealizeBeautyEd permalink*
      January 12, 2021 10:30 am

      If the zinc is sunscreen grade then there should be a safe way to formulate it alongside other sunscreen actives including avobenzone. If the zinc is non sunscreen grade it should not be used as a sunscreen as it is highly likely to form damaging free radicals in the sun that could go on to damage the skin and your other sunscreen.

  8. May 25, 2021 1:15 pm

    I’ve been stressing myself out to no end trying to find the safest sunscreen for my partner and I. He just got a seasonal parks job and is outside all morning and afternoon all weekend, and I’m so concerned. Can you recommend the safest sunscreen that doesn’t have any dangerous chemicals in it? It’s like every sunscreen I research at the grocery has ingredients that aren’t safe, I can’t seem to figure out what will be effective in protection and not also have harmful chemicals. Thank you so much in advance!

    • RealizeBeautyEd permalink*
      July 20, 2021 5:34 pm

      Hi there,
      No sorry I can’t really do that as I don’t really know what chemicals you figure are unsafe. What I can say though is that SPF clothing (as long as you follow the washing instructions well and replace when showing signs of wear) is a good alternative to a slap-on product. So shirts, hats etc that have sun protection ratings of 50 or more are available and are very comfortable, often keeping the wearer cool and bug-free too. Maybe that’s the way to go.

  9. Jason W permalink
    June 14, 2021 5:58 am

    I’m years late to this thread but I’ll add my two cents here. There was nothing “honest” about this sunscreen formula from the start. As the author correctly noted, each % of zinc oxide provides about 1.5 units of SPF. Dispersion improvements in the formulation could be maybe push that to 2 units of SPF per %, but > 3% is ridiculous.

    Instead, what many dis-“honest” manufacturers do is add SPF duping ingredients to their mineral formulas to artificially inflate the SPF while using very little mineral actives in the process. There is a whole industry based on selling SPF duping ingredients (see: http://www.koboproductsinc.com/Downloads/Kobo-SunBoost-ATB.pdf).

    What are some of those SPF boosters? They include niacinamide, centella asiatica extract, bisabolol, butyloctyl salicylate, shea butter, and coconut oil. These ingredients don’t actually protect the skin, but rather mask the biological end point of sun damage so that has the effect of boosting the SPF rating and fooling customers at the same time.

    If you want decent coverage against both UVA/UBV with mineral only sunscreens, an “honest” formulation should include a minimum of 20% zinc oxide as a standalone, or 15% zinc oxide + 5% titanium dioxide.

    With the recent Korean sunscreen scandals overreporting their SPF ratings, the CEO of a sunscreen company wrote an interesting piece about industry practices and I think it’s worth a read (see: https://thesunscreencompany.medium.com/the-purito-sunscreen-controversy-what-does-it-mean-for-the-state-of-sunscreens-and-what-do-e8ae0d8e86ec).

    • RealizeBeautyEd permalink*
      June 14, 2021 8:08 am

      Well thanks for your input Jason but it seems you are missing or misinterpreting some of the nuances that exist in formulating these products. Also the limitations of SPF testing are widely known my formulators so we see the test result as more of a relational thing: how does this compare vs that. The rest is down to application rate, reapplication, age of product when applied, individual skin, health and habits etc. As for my use of the phrase ‘honest mistake’ it was and I have nothing to gain from admitting that. The 1.5-3 SPF units per unit of filter is a very blunt instrument indeed

  10. Paul T permalink
    June 19, 2021 10:38 am

    This is a fascinating conversation! The incredible processes of formulating products is staggering. I have found the chemical sunscreens, notably azobenzene, discolor my clothing. So I took to using the mineral based versions, ZnO and titanium dioxide. There are a whole host of substances that are “inactive”, meaning not calculated to do what the product is intended to do. I found several over the last few years, Coppertone Waterbabies, and Pure and Simple. I’ve got a new one, Bullfrog. A couple of these were combinations and the Pure and Simple is just ZnO. My other curiosity is the expiration dates. I have been using a Pure and Simple container for a couple years now. I discovered it is 6 months past its expiration date! It has worked wonderfully all Spring long and now even in the intense sun we get in the clear air of Montana in June. I called Coppertone and their person said, ” I should not use it.. Given that the actives are relatively stable substances, reminding me of the old ZnO paste that was used by mountaineers, I questioned if it is the “inactive” that shorten the shelf life? Do any of you know? I recall a pharmacist once explaining that expiration dates are set for lots of medicines, prescription and OTC, as the time when they reach 90 or 95% efficacy.

    • RealizeBeautyEd permalink*
      July 20, 2021 5:32 pm

      Thanks for the comment Paul and sorry to take a while to answer it.
      You are justified in giving the idea of ‘past it’s shelf life’ sunscreens a second thought but there may be more going on in the formula than just the actives becoming inactive. Sunscreens are complex arrangements of chemicals in emulsions, gels, sprays or other bases. It may be that over time the formula base shifts somewhat and as such, the role it plays in maintaining the stated SPF reduces too. So you might be able to assay the 6 months past use by date product and find all the listed actives intact but pop it on a test subject and find the SPF only reach 90% or 80% of its stated value due to the film forming capacity reducing, oxidation of aroma or other non SPF actives causing irritation or the effects of gravity on the orientation of the dispersed phase. That sort of thing can definitely happen and while a drop in SPF isn’t necessarily terminal, it does mean the product is not as effective as it used to be and therefore should ideally be discarded. In the worse case scenario the SPF may drop significantly with a shift in product base arrangement and that could be noticable in use. Maybe this product is holding up well though or maybe it wasn’t as intense a UV day as you thought it was when you tested it. Either way, I’m sure most of us have used an expired medicine or sunscreen at times and got away with it just as many of us have used in-date products and been ‘burned’. It’s a dynamic relationship we’re in with our products 🙂

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