Almost Every Doctor Recommends Sunscreen. So Why Don’t We Know More About Its Safety?

Each year, as Memorial Day approaches, Holly Thaggard braces herself for the headlines. About how sunscreen may be damaging coral reefs. About the possible flammability of spray-on sunscreen. Headlines—as there were this year—about how sunscreen contains chemicals that could harm your health.

“This has happened every single year for the last decade of my life,” says Thaggard, founder of Texas-based Supergoop, a sunscreen company that brands itself as reef-safe and free of hundreds of potentially problematic ingredients.

This year, the is-sunscreen-dangerous news cycle started in May, when Valisure, an independent laboratory dedicated to quality-testing pharmaceuticals and personal-care products, released a report warning that its scientists found benzene—a carcinogen also found in vehicle emissions and cigarette smoke—in 78 U.S. sun-care products. Benzene is not an ingredient in sunscreens, but rather a contaminant likely introduced during the manufacturing process, and experts say it’s not clear whether the amount detected in sunscreens could actually lead to health risks. But in July, Johnson & Johnson voluntarily recalled five of its Neutrogena and Aveeno sunscreen sprays due to the presence of benzene. The company stressed that the recall came from an abundance of caution, and that “the levels detected in our testing would not be expected to cause adverse health consequences,” but it still kicked off a fresh flurry of worrisome news stories.

The U.S. Food and Drug Administration (FDA) and the American Academy of Dermatology (AAD) maintain that wearing sunscreen is safe, and crucial to reducing the risk of skin cancer. But it’s hard to blame consumers for asking questions, given persistent concerns about the environmental and health effects of sunscreen. In 2018, for example, Hawaii passed a ban on sunscreens containing the chemicals oxybenzone and octinoxate, for fear they could damage coral reefs. The FDA in 2019 requested extra safety data on sunscreen components as part of a more stringent regulatory strategy. And consumer watchdogs like the Environmental Working Group routinely publish warnings about the potential health risks of sunscreen chemicals like oxybenzone; recently, many have pointed to a 2020 study that found uncertain evidence it could cause thyroid tumors in rats.

As of now, there is no strong evidence that sunscreen harms human health and plenty of data to show that it helps prevent skin cancer. But paradoxically, tighter regulations may be a blessing for the sunscreen industry. As it stands, according to a survey from cosmetic procedures database RealSelf, almost half of Americans say they never wear sunscreen and only 11% wear it every day. And each time a scary new story about sunscreen breaks, Thaggard says, consumers get more and more confused—and perhaps less likely to use the stuff. “Having more restrictions and having more testing only makes it more expensive and only makes it a little bit more difficult” for sunscreen companies to operate, Thaggard says. But, at the same time, “people need to feel good about applying their products.”

Proving they’re safe, once and for all, is the only way to make that happen.

Skin cancer is the most common type of cancer in the U.S. About a fifth of Americans will develop some form of it during their lifetimes, and about 7,000 die from melanoma each year. Those stats are especially striking because most skin cancers are preventable. Many cancers are caused by an opaque confluence of genes, lifestyle and bad luck, making them extremely difficult to avoid. Skin cancer, by contrast, is almost always caused by one thing: excess sun exposure.

The sun gives off two kinds of potentially damaging rays. UVA light causes wrinkles and other markers of aging, while UVB light is the primary cause of sunburn. Both can contribute to skin cancer, so effective sunscreens must block both. They can do so using either physical or chemical filters, or some combination of the two. Physical formulas use minerals—typically zinc or titanium dioxide—to create a physical barrier against the sun’s rays, while the latter use chemicals such as oxybenzone, avobenzone, octinoxate and homosalate to absorb UV light. Mineral sunscreens can leave a telltale white residue on the skin, while chemical formulas tend to sink in more completely.

From a user-friendliness perspective, that easy absorption is an asset. But it’s also the source of some concerns about sunscreen and health.

When the FDA began regulating sunscreens as over-the-counter drugs in the 1970s, it set standards for things like product labeling and testing of a formula’s sun protection factor, or SPF—the measure of how much UVB exposure is required to burn the skin with sunscreen on versus without it. (These days, products labeled as “broad spectrum” protect against both UVB and UVA light.) But the FDA does not actually test individual sunscreens—or any cosmetics or personal-care products, for that matter—before they hit shelves. As long as sun-care companies formulate their products using a set list of active ingredients laid out by the FDA, and follow its guidelines for manufacturing and testing, they do not have to apply for agency approval prior to selling their goods. While the FDA sets the standards they must follow, companies are responsible for their own safety, efficacy and quality testing.

That hands-off approach is, in part, due to an outdated regulatory standard. The agency began beefing up its safety-testing requirements after most sunscreen ingredients had already been on the market for years, essentially grandfathering them into approval without much oversight. And for years, scientists thought sunscreens sat atop the skin rather than penetrating it, exempting manufacturers from the safety testing required for products that can be absorbed into the body.

That assumption was wrong, according to a body of research that includes a pair of FDA studies published in 2019 and 2020. They found that ingredients commonly found in chemical sunscreens, including oxybenzone and octinoxate, can penetrate the skin and seep into the bloodstream, lingering in the body for days at a time. That doesn’t necessarily mean those chemicals are harmful—in fact, the studies’ authors urged consumers not to stop wearing sunscreen because of their findings—but it raises the stakes for finding out if they are.

So far, the research looks fairly comforting. A 2020 research review published in the International Journal of Dermatology found no conclusive evidence that either oxybenzone or octinoxate causes health problems. It did note that oxybenzone exposure (which can also come from the use of other personal-care products) is associated with changes in hormone, kidney and thyroid function, but concluded that there’s not enough evidence to establish cause and effect. A 2021 report from the European Commission’s Scientific Committee on Consumer Safety also noted that, while there are concerns that oxybenzone may disrupt hormones, those data are “not conclusive.” It did say, however, that products should only be considered safe if oxybenzone makes up no more than 2.2% of their formula; U.S. sunscreens can contain up to 6% oxybenzone.

Dr. Henry Lim, a dermatologist at Michigan’s Henry Ford Health System and a past AAD president who has done research and consulting for multiple personal-care brands, notes that sunscreen ingredients have been around for decades, and there’s no evidence that they’ve caused population-level health issues. So why the persistent concerns about sunscreen’s safety?

In some animal research, chemicals like oxybenzone and octinoxate have been linked to reproductive and hormonal disorders. While there’s no concrete proof that the chemicals harm humans, oxybenzone has also been detected in the breast milk of women who report using cosmetics that contain UV filters, as well as in humans’ urine. Contamination issues, like this year’s benzene scare, are another trigger for concern, particularly given the FDA’s laissez-faire regulation of personal-care products.

Dr. Jennifer Beecker, a Canadian physician certified in emergency medicine, family medicine and dermatology, adds that people are, in general, more attuned to the chemicals they put on and in their bodies than they used to be. That’s understandable, after several recent high-profile incidents in which beauty products were linked to health issues—perhaps most notably Johnson & Johnson baby powder’s connection to the cancer mesothelioma.

“Everything in the world is a chemical,” Beecker says, and many are harmless. Even still, consumer concerns about chemicals and potentially unsafe ingredients may help propel the “natural beauty” industry to a nearly $50 billion valuation by 2025.

When it comes to sunscreens, it’s not only personal health that has some people nervous. Sun-care products’ effects on the environment have also been a major topic of discussion in recent years—one that researchers are still trying to understand.

When you go for a swim in the ocean after applying sunscreen, or shower at the end of the day, some can wash off your body and end up in waterways. That, according to the National Ocean Service (NOS), could be a big problem. When certain sunscreen chemicals—including oxybenzone and octinoxate—contaminate aquatic environments, they may bleach or kill coral and cause reproductive issues and birth defects for fish, mussels and sea urchins, the NOS says.

In 2018, Hawaii became the first state to ban the sale of sunscreens using oxybenzone and octinoxate, citing their potential damage to coral reefs. The policy went into effect in January of this year, and Key West, Aruba, Palau, the U.S. Virgin Islands and several other tourist destinations have followed suit. “We’re dealing with living beings, and beings that have just as much of a right to be here as we do,” says Hawaii state senator Mike Gabbard, who introduced the bill.

Gabbard this year pushed for an expansion of the policy, which would have also banned the sale of formulas containing avobenzone or octocrylene in Hawaii, but it didn’t pass. He says he plans to try again next year, with a bill that would ban all chemical sunscreens in several marine life conservation districts in Hawaii.

Lim says such legislation may be premature. A research review published in the journal Environmental Toxicology and Chemistry this year found that while sunscreen ingredients are commonly found in ocean water, they may not collect at levels great enough to actually harm coral. The most concerning research around sunscreen chemicals and coral, Lim says, occurred in laboratory settings, not under real-life conditions. (Gabbard says he stands by the policy and the research review that went into it.)

For both people and the planet, Lim says, there is no clear-cut proof that sunscreen is harmful. But there have been enough rumblings about potential issues associated with sunscreen, he says, to justify revamping the FDA’s regulatory process.

In 2019, the agency announced plans to do just that. At that time, the FDA said zinc and titanium dioxide, the basis for most mineral formulas, could generally be considered safe—but asked the sun-care industry for more safety data on a dozen commonly used chemical filters, including oxybenzone and octinoxate, about which less is known. In May of this year, the agency also announced its intent to assess sunscreens’ effects on the environment. An update to its regulatory policy is expected in September. That could bring new rulings on ingredient safety; the addition or elimination of some chemicals from the agency’s approved active ingredients list; and/or more guidance on the production of newer sunscreen formats, like sticks and powders.

In a statement to TIME, an FDA spokesperson said the agency is assessing the claims in Valisure’s benzene report, noting that “if the FDA’s testing raises any safety concerns, the FDA will work with manufacturers to address these concerns.” The spokesperson did not offer details on how the agency’s regulatory process may change in September, but said “drug manufacturers are responsible for following current good manufacturing practices and ensuring the safety and quality of their products.”

If the FDA does provide substantive new information about or requirements for ascertaining sunscreen safety later this year, it could mean a seismic shift for the sunscreen industry, which has thus far existed without much supervision. ​​Most companies, at least publicly, say that’s a good thing. “Our members are committed to continue working with the FDA and leverag[ing] our industry’s formulation expertise to further demonstrate the safety of UV filters in sunscreens,” reads a statement from the Personal Care Products Council, a trade group that represents many sunscreen and cosmetics manufacturers, including Edgewell Personal Care, the parent company of brands like Banana Boat and Hawaiian Tropic.

Johnson & Johnson, which owns brands like Neutrogena and Aveeno, did not respond to TIME’s questions about its post-benzene-recall testing plans, nor its stance on additional FDA regulation.

Supergoop, for its part, retains a Washington, D.C., public relations agency with one job: booking CEO Thaggard meetings on Capitol Hill, where she can stress the regulatory needle she feels the FDA must thread. Thaggard says her company supports the need for closer studies of sunscreen ingredients, and voluntarily avoids using oxybenzone and octinoxate. But making innovative sunscreens that people of all skin types and colors actually want to wear, she says, requires the freedom to innovate—and a variety of available ingredients.

Some dermatologists share her concern. Already, Lim notes, U.S. companies must work from a shorter list of approved ingredients than Europe’s. “If, say, one knocks out oxybenzone, it would be significantly more difficult for the industry to make a good product in the U.S.,” he says. The National Academies of Sciences, Engineering and Medicine, a nonprofit that often provides scientific analysis to the government, is currently weighing the potential health and environmental benefits of eliminating ingredients like oxybenzone against the potential public health downside of limiting the number of sunscreen products on the market.

Beecker adds that independent testing is an important way to ensure that brands are manufacturing their products properly. The questions that remain are, first, who would oversee that process, and second, whether brands would agree to it.

On the second point, at least, the answer may be yes. Running studies or submitting to extra testing is an expensive hassle for sunscreen companies, to be sure. But if the FDA can put safety concerns to bed, potentially coaxing more people into wearing sunscreen daily, manufacturers stand to gain—and so, in theory, would the public. An uptick in sunscreen usage would hopefully mean a downturn in cancer diagnoses, and healthy returns for the companies lining drugstore shelves with SPF lotions, sprays and gels.

As consumers await the FDA’s ruling, Beecker says they shouldn’t concern themselves too much with their sunscreen products.

“UV radiation is a well-established carcinogen…. Every day I have to tell patients very bad news because they have skin cancer,” she says. “We have tons of data that sunscreen prevents [skin cancers] that kill people. I still think the benefits way outweigh the risks.”