The Environmental Working Group’s (EWG) 2015 Guide to Sunscreen has gone viral these past few weeks, and I have been asked about it by numerous friends who are surprised by the conclusions. People are shocked that the EWG names Neutrogena sunscreens as the number one sunscreen to avoid, despite this brand being dermatologist recommended, and the report labels two key sunscreen ingredients, among a list of others, as toxic: oxybenzone and retinyl palmitate. As a dermatologist in training, I think it’s pretty much my duty to explain the scientific data behind these claims. So don’t go rushing off to toss your Neutrogena sunscreens in the trash just yet.
1). Oxybenzone
The claim: acts as estrogen in the body, causes endometriosis in women, lowers sperm count in men
The truth: Oxybenzone, belonging to a class of compounds called benzophenones, is a UV-A and UV-B filter that has been used in sunscreens since the 1980’s. People became concerned due to studies done in rats and fish or in skin cells grown in petri dishes showing that oxybenzone affected hormone levels. One such study showing that rats that were fed this ingredient developed larger uterine weights which was thought to be from estrogenic effects of oxybenzone. First of all, humans and rats (or fish or skin cells grown in dishes in a lab) are VERY different, and extrapolating animal or cell data to humans directly is dangerous and requires further study. But another important point to note is just how much oxybenzone were the rats fed? A subsequent study found that it is nearly impossible for a human to apply as much oxybenzone-containing sunscreen to get an equivalent dose of what the rats took in orally (ie a human would have to apply sunscreen to 100% of the body everyday for 70 years straight to take in the same amount of oxybenzone those rats got). As the authors write, “…we hope that this analysis helps to place into perspective the doses reported by the in vivo study from which inappropriate conclusions have been drawn and considerable controversy has developed.”
But enough about animal data, which we know is difficult to apply to humans. What about data looking at the use of oxybenzone in actual humans? What we want is the gold standard in clinical testing: a randomized controlled trial in humans. A study published in 2004 had human volunteers apply oxybenzone containing sunscreen to their bodies daily for two weeks and researchers measured their hormone levels afterwards. They found no significant difference in hormone levels between the groups compared to the controls. Interestingly, this one study testing oxybenzone on humans was not reported anywhere on EWG’s website.
2). Retinyl palmitate
The claim: speed development of skin cancer when exposed to sunlight
The truth: Retinyl palmitate (RP), which is the form of Vitamin A naturally stored in human skin, has been called into question because of preliminary data from a series of unpublished studies done by the FDA between 2002-2009. One large study done in rats showed that rats with a certain percentage of RP application on the skin and then UV irradiation developed more malignant (read: cancerous) lesions. There’s a few problems with this though. In groups of rats receiving the highest amount of UV radiation, there was no difference between animals getting RP vs. nothing. That’s odd, because if you expect RP to cause skin cancer when exposed to UV radiation, then higher amounts of UV radiation should lead to more skin cancer. Also, these test rats were actually a special breed of rats that were more prone than normal rats to developing skin cancer to begin with! 82% of these special rats that didn’t get any RP on their skin still went on to develop cancer. So how can you be certain that the skin cancers found were from RP or if that rat would have gotten skin cancer anyways? The answer is you can’t.
As Dr. Wang and his colleagues from a prominent cancer center (Memorial Sloan Kettering Cancer Center in NYC) published in a highly ranked dermatology journal in 2010: “In conclusion, based on currently available data from in vitro, animal, and human studies, there is no convincing evidence to support the notion that RP in sunscreens is photocarcinogenic.”
3). Methylisothiazolinone (MI)
The claim: causes skin allergies
The truth: Methylisothiazolinone, or MI, is a widely used preservative in sunscreen. The EWR cites this paper as evidence that MI is an allergen in sunscreens made for babies; however, on actually reading this paper, the study done is merely a survey of how many brands in a drug store contain MI as an ingredient. There is no data looking at cases of skin allergies caused by MI. Also, the researchers in this paper report that “In cases of recalcitrant dermatitis … allergic contact dermatitis to MI…must be considered as a possible causative factor.” Boiled down, this means that in children with severe skin allergies for which no doctors can find any cause, it is worth considering MI as a possibility when everything else has been exhausted. As you can imagine, this does not apply to the majority of the population. However, as I mentioned above, there is no data actually linking MI to skin allergies.
The skinny: So, in conclusion, after doing a thorough dig into the scientific literature on these key ingredients in sunscreen, I am not convinced by and don’t agree with the EWG’s claims. Sunscreen application including ingredients such as oxybenzone and retinyl palmitate is still a proven way to protect your skin against skin cancer and aging, and the many benefits of sunscreen greatly outweigh any potential risks that are not proven to be real at this point.
So hold on to your products, folks! And don’t forget to use daily application of SPF 30 sunscreen to sun exposed areas. I’ll go over physical vs. chemical blockers in sunscreen in a later post!
For more information:
This was a GREAT article – from a fellow dermatology colleague in training
Thank you Elyse! I hope that this can help spread the scientific truth so people don’t get the wrong idea about using sunscreens.
I loved this article! A few years ago I heard similar myths about sunscreen, particularly to not use Neutrogena for the ingredients in it. I tried switching to other sunscreens with fewer ingredients, but they had less desirable consistencies (those zinc ones spread really thick and white on the skin) so I finally asked one of my friends who’s entering dermatology if those claims I heard about sunscreen ingredients are actually true. She had a similar explanation as you did about the experiments on rats, and your article really solidifies that sunscreen is safe even with the chemicals above. I love how this article you wrote breaks down the argument against each individual ingredient that is controversial with references to the studies that support your argument. Super helpful.
Sarah, thank you so much for your kind words and thank you for stopping by and visiting my blog! This article was so near and dear to my heart because sun protection is the #1 way to prevent skin cancer and aging. The fact that the Environmental Working Group report went viral with such inaccurate data made me so frustrated. I hope you can help spread the word for people to continue using their sunscreens!
Joyce, love your blog. I’m applying for residency next year and have found your blog super helpful.
Also love this article. I just wrote a similar post about how the EWG distorts studies done on animals and applies them to human beings. You can check out my post at dermprincess.com.
Giselle, love your blog! Your infographics are awesome and on point and it’s great that as a medical student you are so involved with social media and blogging. Hope you will find some of my “Path to MD” blogposts helpful; I published a post on how to rock residency interviews today. Stay in touch!
Thank you! I’ve been seeing many Instagram posts about a brand called beautycounter, would you mind sharing your opinion on their products? Even if it’s just based on their websites information. I found out about the EWG from one of their sellers and I was already considering throwing out all my cosmetics. After reading a few of your articles I think I’ll hold on to them and do more research. Thank you so much for all the great information you provide!
Hi Deya, I am not familiar with Beauty Counter products, but I took a look at their website. They take on a more natural approach to beauty with a strict list of ingredients they do not use. Some of the ingredients on their list, such as oxybenzone, are not actually scientifically proven to be harmful (see my post on why oxybenzone is not scientifically proven to be harmful here). I was also surprised to find that they include retinyl palmitate and retinol on that list of harmful ingredients, since in dermatology we use retinoids for skin cancer and acne prevention and it is our go to medication for anti-aging, proven to reduce dark spots and fine wrinkles. I was wondering why beauty counter didn’t have an antiaging product section, but I guess if you take out retinoids, there aren’t many scientifically proven ingredients that work in that arena! Thanks for letting me know about this brand!
I forgot to ask on my other post, what are your thoughts on the consumption of collagen as a dietary supplement for skin ?
Hi Deya, no scientific evidence exists for consumption of collagen for skin benefits. The truth is that ingested collagen is seen as protein in the stomach whether it comes from a special collagen drink or from pig’s feet, and it will be further broken down into amino acids and used for the body in general. It will not specifically go towards the skin.
Hi Joyce, thank you for writing this informative and helpful post! What are your thoughts about Octinoxate? I’ve been using Elta MD for a few years now and I love it, but they use Octinoxate as one of their ingredients. I’ve read that it is a hormone disrupter. What are your thoughts?
Hi Sandy,
Octinoxate is safe, here is one such study testing real world application of this product. Studies claiming harm from this ingredient are ones in which it is fed orally to animals at doses way higher than we would use applying it on our skin. Hope this helps!