• Health

How Sunscreen Became Controversial

6 minute read

Wearing sunscreen every day sounds like a no-brainer piece of health advice. Research suggests regular sunscreen use reduces the risk of potentially deadly skin cancers like melanoma, as well as visible signs of skin aging. The American Academy of Dermatology states its position in no uncertain terms: Everyone should wear sunscreen every day they’ll be outside.

But there’s been mounting pushback to that idea in recent years, mainly due to concerns about the health risks associated with chemicals in many popular sunscreens. These days, it’s not hard to find sources—including influencers, marketers, consumer-protection groups, and scientists—raising questions about the safety and necessity of sunscreen.

Here’s how sunscreen became controversial—and how to interpret safety concerns.

Why is there skepticism about sunscreen?

There are two main types of sunscreens: chemical and mineral formulas. The former use organic filters to absorb potentially harmful UV rays. About a dozen of these filters are commonly used in the U.S., including oxybenzone, octinoxate, avobenzone, homosalate, and octocrylene. Meanwhile, mineral formulas create a physical barrier against the sun’s rays using inorganic filters like zinc and titanium dioxide. Much of the concern about sunscreen centers on the chemical formulas.

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In 2019, the U.S. Food and Drug Administration (FDA) requested additional safety data from sunscreen manufacturers. At the time, the agency said zinc oxide and titanium dioxide should be “generally recognized as safe and effective,” while PABA and trolamine salicylate, two lesser-used chemical filters, should not. The agency said it didn’t have adequate evidence to determine whether other chemical filters could be considered safe and effective. That doesn’t necessarily mean other chemical filters are unsafe, only that regulators wanted more data about them—but the FDA’s request kicked off a flurry of headlines about the potential risks of common sunscreens.

Then, in 2019 and 2020, FDA researchers released two studies that reached the same conclusion: Common sunscreen chemicals, including oxybenzone, can pass through the skin and into the bloodstream. That finding also sparked alarm among some consumers, even though the researchers encouraged people to keep wearing sunscreen.

Adding fuel to the fire, a lab in 2021 found the carcinogen benzene in many suncare products, and big brands including Coppertone issued recalls. The same year, Hawaii began enforcing a sales ban on sunscreens containing oxybenzone and octinoxate, citing harm to coral reefs. Other localities have enacted similar policies, raising concern about the environmental as well as physiological effects of sunscreen.

Are the concerns about sunscreen legit?

Researchers have found that frequent sunscreen use is linked to higher oxybenzone levels in urine. But studies haven’t concretely proven the absorption of UV filters is dangerous to humans.

“The question is, is that significant? Does it mean anything?” says Dr. Victoria Werth, a dermatologist at Penn Medicine who is also board-certified in internal medicine. “Just because you can measure it doesn’t mean it’s a problem.”

There are some concerning signals. Some studies have found links between sunscreen chemicals, namely oxybenzone, and changes in hormone, kidney, and reproductive function, and animal research has raised questions about whether oxybenzone may increase cancer risk.

But “it’s really hard to say, ‘Would that really happen in the human body?’” says Dr. Archana Sadhu, an endocrinologist at Houston Methodist Hospital. Animal and laboratory research doesn’t always translate to real-life conditions. Animals’ bodies work differently than humans’, and real people may not use sunscreen at dosages or frequencies comparable to those in lab studies. (European scientists have, however, recommended capping oxybenzone and homosalate concentrations at levels below those used in U.S. products.)

Similarly, much of the research on sunscreen and coral damage has occurred in the laboratory, rather than under real-world conditions, leading some researchers to question whether sunscreen is actually damaging ocean life enough to necessitate bans on certain formulas.

Should I still wear sunscreen?

The FDA, U.S. Centers for Disease Control and Prevention, and many medical associations all recommend using sunscreen. An estimated one in five people in the U.S. will develop skin cancer during their lifetimes, and more than 7,000 people in the U.S. die from melanoma every year. Sunscreen can help prevent those outcomes.

Ultimately, Sadhu says, most people are better off reaping that known benefit, rather than swearing off sunscreen due to unclear risks. Plus, she notes, people are exposed to potentially harmful chemicals constantly, whether in beauty products, plastics, food and water, or the environment. “It’s not like you’re making this one switch and all of a sudden you’ve made your risk zero,” Sadhu says. People who are worried, she says, would likely be better off ditching cosmetics—which typically have no health-related purpose—than sunscreen.

Physicians often recommend mineral-based products to people who are concerned about sunscreen safety. There is some inconclusive evidence about whether titanium dioxide particles can be absorbed into the body or cause health problems, but mineral sunscreens are generally considered less-risky than chemical-based products.

The consumer watchdog Environmental Working Group (EWG) evaluates the safety and efficacy of sunscreen formulas, and the “vast majority” of products that receive its top scores are mineral formulas, says David Andrews, one of EWG’s senior scientists working on sunscreen. (Since last year, EWG has tracked a 50% drop in the number of non-mineral sunscreens that use oxybenzone, a shift Andrews thinks is driven largely by safety and environmental concerns.)

Andrews agrees that consumers shouldn’t stop wearing sunscreen, but warns the products can provide a “false sense of security.” Some consumers overestimate the efficacy of sunscreen, staying outdoors longer than they otherwise would and increasing their overall sun exposure. Instead of relying solely on sunscreen, Andrews says, people should wear protective clothing, seek out shade, and limit their time in the sun.

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Write to Jamie Ducharme at jamie.ducharme@time.com