In this blog post:
Real life vs. Laboratory Conditions
Every year, as things start to heat up, our thoughts turn once again to sunscreen. What SPF do I need? Mineral or chemical? Is this going to make me stickier than an ice cream on a hot day? How much should I use? (Hey Tiktok, it’s more than 2 fingers’ worth.)
To add to the noise, sunscreen often gets caught in the crosshairs of websites and newspapers alike. Not too long ago, there was an FDA bloodstream study that showed that sunscreen ingredients were found to be present in the bloodstream, lighting a match under a powder keg of alarmist headlines. Reading articles about ‘dangerous sunscreen chemicals’ leaching into our bodies is enough to make even the most steady sunscreen users twitch.
Do sunscreen ingredients get into our bodies? Is it dangerous? Should I be worried? Let’s answer some of these questions so you can get back into the sun - with your SPF on, of course.
Headlines or Clickbait?
The internet isn’t exactly, ahem, averse to drama. Well respected newspapers aren’t immune to the temptation to create consumer-tasty, fear-inducing headlines, causing many scientists to throw their hands up in resignation. When a headline is inducing a knee-jerk reaction, odds are there is more to the story. This is definitely the case with sunscreen.
“Seven sunscreen chemicals enter bloodstream after one use, FDA says, but don’t abandon sun protection” - CNN, January 21, 2020.
“Sunscreen chemicals accumulate in body at high levels” - The Wall Street Journal, July 17, 2020.
“How safe is sunscreen?” - The New York Times, June 10, 2019.
Don’t panic. Let’s not do anything crazy. Remember:
One thing we can agree on? Casting doubt on a life-saving product like sunscreen as a whole is neither helpful, nor scientific.
Is This the Real World… or a Lab?
Testing and safety standards are necessary, but not perfect. In the case of substances in the bloodstream, the FDA set a standard limit of 0.5ng/mL as a “safe” amount. For every substance. This sort of all- encompassing, non-substance specific standard doesn’t give us a clear idea of what a safe concentration of sunscreen is.
What should be considered an acceptable level of absorption really depends on the substance. For example, ethanol is considered toxic when it reaches 80000ng/mL - way past the 0.5ng/mL limit. Setting one amount as a standard limit for everything isn’t an accurate way of measuring the safety of many different substances. In the case of the FDA study, sunscreen actives were flagged for passing the 0.5ng/mL limit, but this doesn’t mean that the specific substances aren’t safe.
There’s also the issue of how well lab results are able to reflect real-world practices. In this study, a standard thickness of 2 mg/cm² was applied to 75% of the subject’s body, 4 times a day. If you think about your own sunscreen-wearing habits, it’s unlikely you’re applying that much product, over that much of your body, that many times a day. How much sunscreen the test subjects absorbed therefore probably wouldn’t be an accurate reflection of how much you would absorb with regular use.
Lastly, news is not always new news. Scientists have known that ingredients get absorbed into people’s urine and blood - this is why the established limit of 0.5 ng/mL was created. This information may have entered your radar recently, but it’s something scientists already knew. There’s no conspiracy here - so far, they haven’t found anything to justify changing how we use sunscreen.
The Truth is Not Always Satisfying
What we know, is that more research is needed. We don’t really have conclusive results as to how the substances absorbed affect our bodies. While this isn’t the most satisfying ending to the sunscreen saga, it’s the most accurate.
We know that there’s no correlation between sunscreen filters and cancer or endocrine disruption.
We know that sunscreen is still an absolutely necessary product. It protects our skin from skin cancer and photo-aging.
We know that the kooky DIY “natural” sunscreen recipe you saw on YouTube is a no-no.
We don’t completely know how safe absorbed chemicals are, but we also don’t know that they aren't safe.
The science machine keeps chugging on, and we’ll know more later.
Takeaway
- Headlines are designed to create drama, but don’t explain the whole issue.
- Lab results don’t always do the best job reflecting how products are used in real world practices.
- You should 100% still be using sunscreen every day, all day.
- Science is an ongoing process. Consumers are learning more about sunscreen, how much to apply, when to reapply etc. Scientists are still learning too.
References
- Matta MK, Florian J, Zusterzeel R, et al. Effect of Sunscreen Application on Plasma Concentration of Sunscreen Active Ingredients: A Randomized Clinical Trial. JAMA. 2020;323(3):256–267. doi:10.1001/jama.2019.20747
- Michele, T. (2021, January 21). Shedding more light on sunscreen absorption. U.S. Food and Drug Administration. https://www.fda.gov/news-events/fda-voices/shedding-more-light-sunscreen-absorption
