Does Sunscreen Really Absorb Into Your Bloodstream?
Apparently, it does, according to new research—but does that mean sunscreen is unsafe?
No matter the season (yes, even if it's not summer), you should be applying sunscreen every day, 365 days of the year. But even if you're already diligent with your daily lathering (you go, Glen Coco), how much do you really know about those creams and sprays you apply to your skin? For instance, did you know that sunscreen can absorb into your bloodstream? Apparently it's a thing, according to a new study from the Food and Drug Administration (FDA). (Related: The FDA Is Aiming to Make Some Big Changes to Your Sunscreen)
If this sounds familiar, that's because this new study is a follow-up to research published in May 2019. In last year's study, researchers asked participants to apply one of four different types of sunscreen—a cream, lotion, or one of two sprays—over 75 percent of their body, four times daily (i.e. the maximum recommended daily dose, the study explained). Participants also submitted 30 blood samples over the course of the seven-day trial period, and researchers ultimately found that four commonly used active sunscreen ingredients (avobenzone, oxybenzone, octocrylene, and ecamsule) were absorbed into participants' bloodstreams.
Piggybacking on last year's study, the one published in JAMA this week was larger in size (48 participants vs. 24) and tested more active sunscreen ingredients (6 chemicals vs. 4). Researchers from the Center for Drug Evaluation Research at the FDA recruited 48 volunteers for a random clinical trial study to find out whether active ingredients (avobenzone, oxybenzone, octocrylene, homosalate, octisalate, and octinoxate) in four commercial sunscreens absorb into the bloodstream. More specifically, they were looking to see if the ingredients exceeded 0.5 nanograms per milliliter of blood—the FDA-recommended safety threshold, per the study.
Similar to last year's research, volunteers in the new study applied one of four different types of sunscreen—a lotion or one of three sprays—over 75 percent of their body, four times daily. Participants also submitted 34 blood samples over the course of the 21-day trial period. In the end, researchers found that all six active ingredients had reached blood concentrations beyond the FDA safety threshold after just one application. What's more, the blood concentrations increased over time, according to the study's findings. (Related: Is This Controversial Ingredient In Your Sunscreen Doing More Harm Than Good?)
Though the idea of chemicals absorbing into your bloodstream might sound unnerving, it isn't necessarily unsafe, according to the FDA's press release. (Repeat after me: Absorption does not equal risk.) It just means that further research needs to be done in order to determine the ingredients' effects and to definitively say whether the ingredients are safe for regular application. And the good news is that the FDA has already taken a step in that direction: In February 2019, the FDA proposed a rule that would require sunscreen manufacturers to provide additional information on the active ingredients in their products. While these two existing studies support the proposed rule, the FDA says it has asked "industry and other interested parties" for additional safety studies to better understand these ingredients, according to the agency's press release.
What is currently known, however, is this: Sunscreen works in one of two ways. Chemical sunscreens are absorbed into the skin; they absorb UV rays, convert those rays into heat, and release them from the body, says David E. Bank, M.D., a board-certified dermatologist based in New York. Physical sunscreens, on the other hand—whose main ingredients are zinc oxide and titanium dioxide, both considered safe and effective by the FDA—sit on top of the skin and reflect UV rays, explains Dr. Bank.
Avobenzone, oxybenzone, and octocrylene (three of the six chemicals the FDA tested most recently for traces in the bloodstream), "are ingredients used in sunscreen to block UV rays to protect the skin from DNA damage," says Dr. Bank. And as far as experts know, these ingredients are not dangerous to humans, he adds. (Related: Sunscreens for Working Out That Don't Suck—or Streak or Leave You Greasy)
"The risk of not using sunscreen outweighs the benefits of not wearing sunscreen," explains Dr. Bank. "For those concerned about these chemicals, physical sunscreen containing zinc oxide, like the Jack Black Sun Guard SPF 45, is a great alternative to protect against both UVA and UVB rays. In addition to sunscreen, people should wear protective clothing that covers the skin and seek shade during hours of peak sunlight."
Bottom line: Some sunscreen ingredients may absorb into your bloodstream, but you should still continue to lather up regardless, at least until further research has been done on the subject.