TikTok’s sunscreen misinformation problem
Expert
Dr Michelle Wong (aka Labmuffin Beauty Science): chemistry PhD, science educator, cosmetic chemist
Claims
DIY sunscreens are more effective “natural” alternatives to store brands
Seed oils in sunscreens cause skin damage
Higher SPF sunscreens aren’t more effective than lower SPF ones
Sunscreen use has led to an increase in skin cancer rates
Chemical sunscreens disrupt hormones and are unsafe
Reality
Misinformation about sunscreen is rampant on TikTok—and in virtually every other social media channel imaginable. A number of wellness influencers, biohackers, and optimizers have spread the myth that sunscreen is dangerous, some going so far to say that since the sun is “natural,” it can only be beneficial for our health. Indeed, while vitamin D is essential, the claims by these influencers are dangerous when they cause people to stop wearing sunscreen.
Dr Wong offers a deep dive into all the claims above in this 45-minute video. Below are a few highlights, with more explanations in the resources section.
DIY sunscreens are generally not great. Effective sunscreen isn't just about the percentage of zinc oxide in a product, but how that zinc oxide is distributed in the sunscreen and how it spreads on your skin. You might have the same weight and percentage as a commercial brand, but it might be in one big lump instead of spread out through the sunscreen, which will cover up more skin and block more UV. Smaller zinc oxide particles also absorb more UV and reflect less visible light, so they work better as a sunscreen—plus they look less white.
Seed oils in sunscreen do not cause cancer. As Dr Wong points out, in recent years this idea has been adopted from nutrition (where it’s also untrue) and applied to sunscreen. The basic idea is that linoleic acid and omega 6s make skin “fragile,” though Dr Wong shares literature that shows the opposite is true: linoleic acid gets turned into specific serums that make your skin less dry and flaky.
Higher SPF sunscreens work better. But perhaps not for the reason you think. A lot of testing happens in laboratories, not real-life, where people often under-apply sunscreen. Studies have found people get burned less with SPF 100 than SPF 50 because of real-life conditions where people don’t apply enough, or don’t properly spread out the sunscreen. The gist:
If you have two sunscreens that you like equally, the one with higher SPF is going to give you more protection.
Sunscreen doesn’t cause cancer. The data in question comes from a graph showing an increase in melanoma rates since the 1970s, when commercial sunscreen became more widely available. As Dr Wong states, correlation isn’t causation, and there’s no line for sunscreen use in the data presented. It’s just a false correlation that became a TikTok myth. Numerous studies show that regular sunscreen use results in a lower incidence of melanoma.
Sunscreen isn’t a hormone disruptor. The dose makes the poison. Influencers tend to get dosing levels exceptionally wrong, or not even take them into account. When they see a chemical listed that can be carcinogenic at high levels, they assume it must be carcinogenic at every level. The same goes for endocrine disruptors, which is the claim in question. As Dr Wong points out, allowed percentages are also just a tiny fraction, usually 100th of an amount that still shouldn't give any tiny potentially harmful effect. In context, the EU allowing 2.2% oxybenzone versus the US allowing 6% is not a huge difference. It just means that the EU thought that up to 220% was still safe while the US thought that up to 600% was still safe.
Dr Wong emphasizes that both mineral and chemical sunscreens are safe when used as directed, and that the best sunscreen is one that a person will use regularly and in the correct amount.
Resources
Are US chemical sunscreens endocrine disruptors? Scientist explains
