Another U.S. government-led study looking at whether certain sunscreen filters can possibly affect the body is making the rounds. But while its conclusions are worth caring about, you shouldn’t panic, and you definitely shouldn’t stop using sunscreen.
The study, conducted by researchers from the U.S. Food and Drug Administration and published Tuesday in JAMA, recruited 48 healthy volunteers (men and women split evenly) for a randomised experiment.
For four days, they applied one of four sunscreens that contained a total six active ingredients (avobenzone, oxybenzone, octocrylene, homosalate, octisalate, and octinoxate). For 21 days, starting with the first day of sunscreen use, the participants had their blood tested for the presence of these ingredients. The sunscreens used were a lotion, aerosol and non-aerosol spray, and a pump spray.
No matter the ingredient or the way the sunscreen was applied, the researchers found, the ultraviolet filters were readily absorbed into people’s bloodstreams. The average level of these ingredients in people’s blood was higher than the threshold established by the FDA to determine whether an ingredient requires further safety testing. This may sound alarming, but the authors urged caution against people taking their results too far.
“These findings do not indicate that individuals should refrain from the use of sunscreen,” they wrote.
Just because a chemical can enter our bodies does not automatically mean it can cause harm, and sunscreen ingredients have been widely studied around the world and repeatedly found to be safe. For example, a 2001 review by European Commission scientists found that “there is no need for regulatory actions to protect the consumer with regard to potential estrogenic effects of the UV-filters studied.”
The report noted that “The activity of the UV-filters found is very low in comparison with exposure to ‘estrogenic’ substances in food (flavonoids)” and concluded, “As UV-filters are an effective tool to protect humans from excessive exposure to sunlight, a known carcinogen, their use is recommended.”
The new study is an update to a similar, smaller study conducted by the FDA that got a fair bit of media hype last year, which also found that several active sunscreen ingredients were absorbed into people’s bloodstreams.
Both studies are important because of a 2014 law that required the FDA to change its regulation of over-the-counter sunscreens. While the law was meant to speed along the approval of newer UV-filtering ingredients, it also led to the reevaluation of many sunscreen ingredients sold in the U.S. for decades—those used in so-called chemical sunscreens. (Mineral-based sunscreens, made using zinc oxide and titanium dioxide, are also effective at blocking ultraviolet light, but they tend to leave a white cast over the skin.)
In 2019, the FDA proposed new guidelines that would kick 14 common sunscreen ingredients off its “Generally Recognised as Safe and Effective” (GRASE) list. They also asked the manufacturers of 12 ingredients to put forth more evidence for their safety in order to keep selling products made with them. Among the kinds of evidence requested by the FDA were whether these chemicals are absorbed through the skin to any meaningful degree and if that could lead to any health risks.
Right now, the FDA’s research suggests that companies looking to sell sunscreens with these ingredients will need more safety studies. The newer study also provides evidence that casual sunscreen use could expose people to these chemicals, since the ingredients could be found in people’s blood after only the first day of testing, when volunteers were asked to apply sunscreen only once.
Other research has suggested that some of the chemicals found in these products could, in theory, be capable of interfering with our naturally produced hormones, which in turn could affect things like our fertility or risk of certain cancers. But it’s a long road from that theoretical risk to showing that sunscreens made with these ingredients are unhealthy in any way. (In the European Union, a wider and more effective range of chemical sunscreen ingredients have been approved as safe.) At this point, the FDA has not yet cemented a deadline for when sunscreen companies must provide the evidence needed to rule out any health risks nor when any new proposed regulations should come into effect. So for now, these products are still available on the market.
Just remember that these studies aren’t proving that any sunscreens are dangerous, and they shouldn’t convince you to stop using sunscreen altogether. Sunscreen is still one of the best ways to prevent skin cancer, particularly if you have lighter skin (though maybe spray sunscreens in general aren’t the best option).
In an editorial also published in Tuesday in JAMA, dermatologists Adewole Adamson and Kanade Shinkai argue as much.
“It is critical to recognise that these two studies conducted by the FDA do not provide any evidence that chemical sunscreens cause harm,” they wrote.