Is Sunscreen Toxic and What Does It Really Contain? | Chris Kresser
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Are Your Skincare Products Toxic? Sunscreen.


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People are told to slather on the sunscreen to protect themselves from the sun, but could we be doing more harm than good?

is sunscreen toxic
Sunscreen protects us from excessive sun exposure. But it the sunscreen itself toxic?

So far in this series, I’ve discussed why you might want to be wary of conventional skincare products like soap, shampoo, lotion, makeup, and deodorant. In this fourth and final article of the series, I want to focus on sunscreen. “Natural” sunscreens can be a hassle, but there are some very real health concerns associated with the ingredients in conventional sunscreens that might encourage you to seek out nontoxic alternatives.

Aluminum in Sunscreen

We left off last time talking about aluminum in deodorant, and why it might be prudent to avoid. Incidentally, many sunscreens also contain aluminum, so for that reason alone you should use an alternative to conventional sunscreen. For one sunscreen that was analyzed for aluminum concentration, a single application would provide 200mg of aluminum. (1) Another concern is that, as an oxidant, the aluminum in sunscreen might contribute to oxidative damage in the skin, increasing the risk of cancer.

However, of larger concern are the ingredients that actually block UV rays. Sunscreens can block sunlight in two ways: with organic (meaning carbon-based) filters, or with inorganic filters that act as a physical barrier. Let’s start with organic UV filters.

Organic UV Filters: Easily Absorbed, and Potentially Harmful

Evidence indicates that organic UV filters are readily absorbed into the skin. One commonly used UV filter, oxybenzone, was detected in the urine, plasma, and breast milk of human volunteers after full-body sunscreen application, and was found in 96% of urine samples collected in the US during 2003 and 2004. (2, 3, 4) Other UV filters have been detected in 85% of breast milk samples in Switzerland. (5)

Many of these chemicals aren’t very stable when exposed to UV radiation, and they can form reactive oxygen species (including the oft-maligned “free radicals”) and cause oxidative damage. (6, 7, 8) One UV filter, PBSA, has been shown to induce DNA damage in human skin cells after exposure to UV rays. (9) This means that the use of chemical sunscreens could increase the risk of cancer. Some filters even lose their ability to block UV rays once they penetrate the top few layers of skin, rendering them useless. (10) To top it off, these compounds are also a common cause of photoallergic contact dermatitis. (11)

Find out why your sunscreen may be doing more harm than good.

Beyond the local effects from formation of reactive oxygen species (ROS), systemic toxicity becomes a concern, since these UV filters are absorbed into the bloodstream. One of the primary concerns is their potential for endocrine disruption. Several animal and in vitro studies have found adverse developmental and reproductive effects of UV filters. (12)

For example, administration of oxybenzone (the same chemical found in 96% of urine samples in the US) to mice resulted in decreased sperm density and increased numbers of abnormal sperm. (13) And although many animal studies measured toxicity through oral administration, the authors of one review point out that exposure through dermal absorption may pose an even greater toxicity risk because the compounds aren’t digested and metabolized by the liver before entering systemic circulation. (14)

Inorganic UV Filters: Zinc Oxide and Titanium Dioxide Nanoparticles

Inorganic filters are usually nanoparticles of either zinc oxide or titanium dioxide. Like organic filters, both types of nanoparticles can form ROS, particularly when exposed to UV light, and in vitro studies show that they can damage human cells. (15) That said, one study using human immune cells found that levels of ROS generated by nanoparticles in combination with UVA light was not greater than the level of ROS generated by UVA light alone, so nanoparticles might not contribute significantly to oxidative damage caused by sun exposure. (16)

Either way, these effects are only relevant if nanoparticles can actually penetrate the top layer of skin and reach living cells. Their ability to do so is controversial, but most evidence indicates that they can’t. Even in skin that is sunburnt or affected by psoriasis, zinc and titanium nanoparticles only penetrate the top layer of skin (the stratum corneum), which is made up of dead cells, and don’t reach living cells. (17, 18)

That said, sunburn did result in deeper penetration into the stratum corneum, and I certainly wouldn’t dismiss the possibility that repeated application of sunscreen to freshly shaven skin that is then exposed to sunlight for long periods of time (in other words, normal summertime behavior) could cause nanoparticles to make their way into living tissue. And remember those PEG compounds that can enhance the absorption of other chemicals in personal care products? They’re found in sunscreens, too.

Based on the evidence, I would avoid sunscreens using either nanoparticles or organic UV filters. Nanoparticles definitely appear to be the less harmful of the two options, and nano zinc oxide seems to be both slightly less toxic and slightly less apt to penetrate the skin compared with nano titanium dioxide.

But keep in mind that commercial sunscreens also contain many other questionable ingredients, some of which we’ve discussed in previous articles in this series. You’re better off finding a natural alternative, some of which I’ll discuss below.

Nontoxic Alternatives to Sunscreen

One problem with sunscreens in general is that often, they allow us to stay in the sun for much longer than would typically be considered healthy for our skin. We get sunburnt for a reason – it’s our bodies telling us to get out of the sun – and since some sunscreens block the rays that burn us without completely blocking the rays that can cause skin damage, we might be harming our skin without realizing it.

For this reason, the best approach to sun exposure is to build up sun tolerance gradually, and get in the shade or cover up with a hat and shirt once you’ve had enough sun. Tanning is fine – just try to avoid getting burned!

Mark Sisson also reviews some simple dietary changes you can make to prevent sunburn, including eating more antioxidants to protect against sun damage.

That said, I know there are times when you have to (or want to) be in the sun all day, and might not be able to cover up or seek shade. In those cases, I recommend using non-nano zinc oxide sunscreens, which have particles large enough that they aren’t absorbed into the skin. These posts from Wellness Mama and Mommypotamus have recipes for homemade zinc sunscreens, as well as links to good commercially available products.

Environmental Working Group has an online Guide to Sunscreens with tips to keep in mind before you go outside and their latest sunscreen research. They also put together an annual wallet card, Guide to Safer Sunscreens, with tips on how to read sunscreen labels, how to make smart and healthy choices when shopping for sunscreen, and other valuable information.

I hope you’ve enjoyed this series on nontoxic alternatives to conventional skincare products. My intention was not to freak out my readers about the personal care products they use, or to perpetuate the fear-mongering that often accompanies discussions about chemicals we’re exposed to in our daily lives. But while there isn’t (and probably never will be) conclusive evidence that some of these chemicals can cause harm or contribute to toxin build-up in the body, there’s also not conclusive evidence that they don’t.

Given how much our bodies already have to handle thanks to modern life, I don’t see any reason to risk increasing that burden. We can’t really do much about our exposure to pollution or off-gassing building materials or a slew of other toxic things, but it’s so easy to shift to natural, non-toxic personal care products that to me, any evidence of possible toxicity from chemicals in conventional products is enough to sway me to avoid them.

  1. not sure when Chris became a dermatologist – you offer absolutely no scientific evidence that sunscreens, organic or otherwise, are more dangerous than vulnerable skin exposed to sun without SPF. sure there are commericial drug store products that are not healthy and common sense in terms of avoiding sun at peak hours is still the best prevention.

    But to suggest this nonsense about about avoiding sunscreen is dangerous and our article is facile. Skin cancer kills millions of people and sunscreen helps prevent skin cancer – To sway people from using sunscreen is irresponsible and unfounded. period. Hats and shirts great – but SPF is not a consumer myth or a money making scheme. it is the result of years of study and dermatology consensus. Imbibe all the coconut oil you want Paleo people. Sun damage resulting in the absence of sunscreen is lethal. Period.

    • Erica, want to share some info with you here. Sunscreens in the US only block for uvb but they should also block for uva. Ingredients used in Europe have been doing this for years, but we are way behind in the US. It’s frustrating as a consumer!

      Lots of sunscreens are known to be hormone disruptors and this has the most damaging effect on kids.

      Also, SPF 70 or 90 or whatever is extremely misleading. Consumers need to reapply and reapply and reapply sunscreen, but they don’t because they think they’re covered.
      That’s dangerous.

      Protective clothing, great sunglasses uva/uvb (for kids too!), a good diet, and sunscreen that’s safe makes the most sense.

  2. I’ve found that for our blonde-haired, blue- and green-eyed family, that daily coconut oil consumption helps build a better overall tolerance to sun exposure. We frequent FL and have noticed a big difference since adding coconut oil to our diets, especially since the sunscreen cant wash away 🙂

    We will continue to wear our Coolio sunguard shirts tho – sunburns are no fun!

  3. I have a question. I see the Environmental Working Group quoted by every eco-conscious group and individual and, yet, I have never seen an in-depth explanation of how they arrive at their lists of “bad” ingredients or what qualifies them to do such. Who are these people and how did they achieve untouchable status? As you know, Chris, science itself and chemical formulations, specifically, and how the body responds to them are rarely if ever absolutes. I worked for an environmental consulting firm for many years and never did they boldly state “this is good or this is bad, all findings were justified and explained on their RELATIVE safety on the basis of scientific findings. They were, of course, covering their you know what, but somehow the EWG has managed to avoid being questioned about their scientific methods and conclusions. I’d really like to know who the EWG is and why we should trust them.

  4. Since going on an ancestral diet (paleo plus fermented dairy) about 7 years ago, I have noticed a huge increase in my sun tolerance. And like others have reported above, I find that lathering coconut oil on my skin before going out in the sun provides even greater protection against sunburn. If I do get some sunburn, I also have noticed that it does not set in as strongly and resolves more quickly if I put more coconut oil on afterward.

  5. From a classical homeopathic perspective, topical zinc, and I suspect also titanium, is very suppressive to the vital force. I inadvertently proved this to myself several years ago. When the vital force, which normally moves upward and outward, is suppressed in this way (think of it as jamming the energies downward) , new problem areas develop in another place in the system. With topical zinc the most common area of later problem development, will be chronic problems involving the respiratory system. Due to a time lapse sometimes of several years, one might not make the connection, but it’s well known to homeopaths.

    I prefer the old-fashioned commonsense approach of having enough sense to get out of the sun, cover up with clothes and a hat, get into the shade, know your sun limits, back off before you think you’re sunburned.

    Any area of skin that has gotten a lot of sun over the lifetime, such as hands, forearms, and cheekbones, are likely to get hyperpigmentation as we age, especially after age 60 and/or
    if ingesting rancid fats, such as many or most fish oil supplements.

  6. I found out a long time ago that taking B-Complex vitamins will not only prevent sunburn, but is the best treatment for it. I had a terrible sunburn from going to the beach when I got home I took B-Complex and the next morning it was just a nice little tan. Now I take it before and after exposure.

  7. I’ve used coconut oil for a couple of years now too and have had good success with it. As Chris said, “get out of the sun when you’ve had enough”. I used to have a sun allergy and burn easily too but with the coconut oil, eating Paleo and easing in to sun exposure I can tolerate so much more than I used to.

  8. I’ve been wearing coconut oil as sunscreen for years now. I also take antioxidants, juice and eat super healthy overall…but I rarely burn. The stuff in sunscreen never seemed right to me, thanks for laying it all out Chris!

  9. As an alternative, I’d urge people to get tested for their level of Vitamin D. If the level isn’t in the 80’s range, then I’d advise them to start taking Vitamin D3 in whatever form they choose: cod liver oil, D3 supplements, and/or sunshine. As a person of Irish descent, I used to burn at the drop of a hat, even WITH sunscreens! Now that my Vitamin D3 levels have been corrected, I can go out and mow lawns all afternoon, and not even turn pink.

    The doctor will try to dissuade you from self-correction, and say things like, “You’re taking too much.” Don’t mind the doc–mind the lab results. Take as much Vitamin D3 as you need to get your levels up into the 80’s range, and keep them there. D3 is responsible for a whole lot more than just keeping sunburn away, so take what you need. I personally need 5,000 units twice daily, and my husband (of Norwegian descent) needs even more. His doctor tried to dissuade him, but I told him to wait for the labs to come back–I was right, and his doctor was not.

    • If you’re taking high amounts of Vit D supplement, test not only the usual serum 25-D, but also 1,25-D at the same time (the active metabolite of 25-D), since too much D will start to pull calcium from the bones which is then excreted thru the kidneys, hence a kidney stone risk. Make sure 1,25-D is not out of range, though the optimal-within-range has been considered by some sources to be 30. 24-hr urine calcium can also be checked for calcium and oxalates for additional perspective.

      It’s not uncommon with autoimmune disorders, for example, to have low 25-D but high 1,25-D, likely due to high macrophage activity, but can be exacerbated by high Vit D supps and sun exposure.

  10. Pasty redhead here,
    I haven’t had a sunburn in years, but I have deprived myself of sun exposure to achieve that. Sunscreen, between being toxic and being sort of like a sun-suppressant, never seemed right to me. But you are right Chris – gradually building up a tolerance sounds like a good idea. This summer I plan on lying out in the sun in my bathing suit bottoms for a couple minutes, maybe I can work up to 10 minutes ee I can’t imagine (again, pasty ginger). It seems like a better substitute for vitamin D than the synthetic stuff or anything else for that matter.

  11. Great post, Chris. You always do such a good job laying everything out. I never really thought about what I was putting on my skin until a few years ago.

    I have made my own sunscreen (can’t find the recipe so need to dig for that again) and found that one of the “safe” brands I was using isn’t so good. So now I am going to be using Beautycounter and Miessence this year.

    Beautycounter (they are working hard to raise awareness of toxins in beauty products):

    and Miessence (a super clean company across the board):

  12. Hi Chris,

    Thanks for your articles – absolutely love following your conversations and learning more. Living in the UK now, it’s incredible how many toxic ingredients are banned by the EU but not in the US – over 1200! However, still not all ingredients have been banned and as your recent artciles point out – they can be very harmful.

    I have been using Arbonne products for the past year as Arbonne are 100% focused on creating pure, safe and beneficial products – including sunscreens – and they have been doing this for 35 years! Products are Non-comedogenic, Vegan certified, Gluten free, GMO free, Paraben free, Phthalates, and free from synthetic dyes and fragrances.

    I loved them so much I became a consultant so I can educate and help others! If you or anyone else would like to learn more, just get in touch via my website. Happy to help!

  13. Great post, Chris, and just in time for the weather to be warming up. I’ve been taking D3 for the last couple of months, and now I’m focusing on getting outside a bit each day to build up my skin’s tolerance before it gets to really be summer!

  14. For the past ten to fifteen years I’ve been taking ~6,000iu of D3 and using coconut oil (topically and as food) daily. It makes a huge difference in my skin as far as sun tolerance. If I build up exposure gradually in the spring I rarely have to deal with sunburn. I never use sunscreen. I also don’t work in a field or sit on the beach all day. That probably helps.

    • I too have been using coconut oil in the same way and have also noticed a significant increase in tolerance to sunshine. Last year we had the hottest summer for decades and I was out and about on my bike most days, but I didn’t suffer from sunburn once.

  15. Beyond the brain underdevelopment implications of not enough Vitamin D3, there are a wide variety of other implications. Serotonin is well known to be essential for healthy, happy moods. It’s also important in digestive and intestinal health. These are impacted by insufficient UV penetration of our skin. Still unknown are the impact of Vitamin D on hormones similar in structure to serotonin, such as melatonin and DMT. The issue of sunscreens goes much deeper than even the concerning question of the potential toxicity of those screens.

  16. A significant thing to add is that sunscreen may be a contributing factor to skyrocketting rates of autism. A theoretical paper published by Dr. Rhonda Patrick highlighted how serotonin is essential for new neurons to be linked to other neurons. Serotonin acts as an electrician wiring up the new brain cells to each other. However, we need adequate levels of Vitamin D3 to produce serotonin. Adequate levels of UV are essential for Vitamin D3 production. Inadequate sun exposure can mean a poorly developed (and a poorly repairing) brain.