After an extensive clinical study, the agency found that some commonly used sunscreen chemicals — avobenzone, oxybenzone, octocrylene, homosalate, octisalate, and octinoxate — can seep through your skin and into your bloodstream. The study found that even after a single application, the chemicals stay in your body for an extended period of time.
However, the fact that these chemicals get into your blood doesn’t necessarily mean these ingredients are harmful, says David Fivenson, an immunologist and dermatologist in Ann Arbor, Michigan.
Some laboratory studies suggest that chemical ingredients may interfere with the normal functioning of the body’s endocrine system, affect infant development, or cause other health problems.
But Fivenson notes, “There has never been good, practical evidence of harm in a realistic human study.”
If there’s one ingredient to avoid, it’s probably oxybenzone, says Tasneem Mohammad, chief physician in the department of dermatology at Henry Ford Health System in Detroit. “In many parts of the world like Europe, it’s not really used anymore,” says Mohammad.
Oxybenzone can cause allergic reactions, and studies have linked it to hormone problems, lower testosterone levels in boys, shorter pregnancies, and an increased risk of endometriosis and breast cancer. A 2020 study found that rats exposed to the chemical were more likely to develop thyroid tumors.
The FDA has urged U.S. sunscreen manufacturers to do more testing on chemical ingredient safety, but that may take years. In the meantime, the agency has kept the products on the market in the absence of data proving harm.
Mineral-based sunscreens are considered the safest
For now, if you’re concerned about health effects, what’s called a “mineral” or “physical” sunscreen containing zinc oxide or titanium dioxide is the safest choice, dermatologists say. These are only sunscreen ingredients that the FDA says are “generally recognized as safe and effective.”
While chemical sunscreens act like sponges and absorb ultraviolet light, “a physical sunscreen acts like a protective shield,” Gahara explains. It sits on your skin and deflects UVA and UVB rays away from your body.
Physical sunscreens are also a better choice for people with sensitive skin because they cause fewer skin reactions, says Allison T. Vidimos, a board-certified dermatologist and chair of the department of dermatology at the Cleveland Clinic.
“Because a mineral blocker isn’t absorbed into your skin, it’s less likely to clog your pores and tends to be gentler on sensitive skin,” she says.
The downside to physical sunscreens is that they can leave a white residue on the skin, especially on people of color. But many manufacturers have released newer formulas that use micronized particles or tints to minimize chalkiness, Vidimos and others say.
“The sunscreen industry has adapted to the situation and developed tinted sunscreens that don’t look chalky on people with darker skin tones,” says Vidimos. “They even have different tint intensities so you can match your skin tone to the right one.”
Which sunscreens are the safest for the environment?
Mineral sunscreens are also believed to be a better choice for the environment.
Laboratory studies show that some chemical ingredients can be toxic to corals and other marine organisms, says Fivenson, who co-founded a group at the American Academy of Dermatology that studies environmental issues. But the true effects are unclear, as the concentrations of chemicals used in some studies were up to 1,000 times higher than the amount in most real-world settings, he says.
To help answer this question, the National Academy of Sciences convened a panel of experts to review current research on the potential toxicity of sunscreen ingredients to corals and other marine organisms. The committee is expected to publish its findings later this year.
For now, if you’re concerned about the environment or traveling to a place that bans certain chemicals, you can look for sunscreens that say “reef safe” or “reef friendly.”
Note, however, that these conditions aren’t regulated by the FDA, Fivenson says. So you should also check the ingredients to make sure they don’t contain oxybenzone or octinoxate – the chemicals most often banned for their harmful effects on marine life.
Wearing a sunscreen swim shirt can also help the environment by reducing the amount of sunscreen you need to apply.
More advice on choosing sunscreen
In addition to considering a product’s impact on your health and the environment, dermatologists offer the following advice for choosing a sunscreen that offers maximum protection: