In the U.S., this advice, so commonly bandied about, can be a bit tricky to follow. Compared to other places in the world, manufacturers in the U.S. can use only a handful of ingredients. As a result, many American sunscreens are greasy or leave a white cast on the skin. Others contain substances that may make their way into the bloodstream, according to research, though the health effects of this potential leakage aren’t clear.

However, after decades without much appreciable change, the U.S. Food and Drug Administration (FDA) announced in December that they are considering approving a new, powerful sunscreen ingredient called bemotrizinol—a move the Environmental Working Group called "cause for optimism." Experts speculate that the FDA may render a decision on the ingredient sometime this summer. It’s been used in Europe and elsewhere for years, and according to experts, it could revolutionize sunscreen in the U.S. 

What is bemotrizinol?

Sunscreen, as we now use it, is a relatively recent invention. It was less than 100 years ago that scientists made a direct link between ultraviolet (UV) rays produced by the sun and the development of skin cancer. That didn’t affect most people’s behavior for many decades; tanning was a popular pastime for much of the 20th century. However, in the 1970s, the U.S. government began to regulate sunscreens as drugs, reasoning that they could be powerful tools for public health. 

Many early sunscreens contained molecules that blocked one particular class of UV rays, says Kelly Dobos, an independent chemistry consultant who also teaches at the University of Cincinnati. “When sunscreens were first developed and first put on the market, we were concerned about preventing sunburn,” she says. “And the UVB rays are primarily the ones that cause sunburn.” 

The main blocker of UVA rays in U.S. sunscreen is a substance called avobenzone. It’s not particularly stable in the sun, so it has to be stabilized by other molecules. In 2020, studies also showed that avobenzone and other similar ingredients were seeping through the skin and showing up in people’s bloodstream. It isn’t clear what health effects that might have—people weren’t followed over the long term—but the revelation alarmed some scientists. 

“We really need more comprehensive safety testing,” says David Andrews, chief science officer of the Environmental Working Group. But movement has been slow. Sunscreens containing these ingredients have stayed on the market.

Elsewhere in the world, industrial chemists have been coming up with better options for many years. The E.U. approved bemotrizinol as a new sunscreen ingredient in 2000. It’s a broad-spectrum blocker of rays, protecting the skin from both UVB and UVA. Additionally, the molecule itself is much larger than avobenzone, so it stays on the skin’s surface and doesn’t end up in the bloodstream. 

Why has it taken so long for bemotrizinol to reach the U.S.?

The answer has to do with how sunscreen ingredients are tested. Sunscreen ingredients are regulated differently in different countries. In the U.S. and in Australia, they are treated as over-the-counter drugs. In the E.U., they are considered cosmetics. These approaches mean different requirements from regulating bodies. 

The U.S. presents a particularly tricky market for sunscreen manufacturers, however. The bar for proving that new ingredients are safe is high, but the current ingredients on the market, which have been grandfathered in, have not undergone the safety testing that the FDA requires for new substances.

As a result, no new UV-blocking ingredient in sunscreen has been approved in 25 years. 

The cost of proving safety to the FDA has given some manufacturers sticker shock, says Dobos. “The financial implications of meeting those requirements is challenging…so some companies have dropped out of approval of new sunscreen active ingredients,” she says. Uncertainty about the approval timeline can also be a deterrent. Michelle Wong, a chemist and science communicator who writes about skin care and beauty products on her site Lab Muffin, says she’s heard chemists who work at sunscreen companies say they struggle to predict how or when the FDA will respond to tests of sunscreen ingredients. “They've been saying, ‘The U.S. is a mystery,’” she says.

What will bemotrizinol change about sunscreen?

If approved—which the industry expects might happen this summer—this ingredient will open the door to quite a few new options, says Wong, who is based in Australia. “It's kind of difficult to formulate sunscreens in the U.S…there's a limit to how much avobenzone you can shove into a sunscreen.” 

Using bemotrizinol instead may mean getting to ditch the stabilizers and other substances needed to make avobenzone effective. In Europe and other places that allow the ingredient, it enables options that are less greasy and easier to use regularly. “With bemotrizinol, you can reduce the number of filters and reduce the total percentage of filters, and that helps you get to a more elegant feeling product,” says Dobos. 

“It is one of my favorites,” Wong says, noting that bemotrizinol doesn’t leave a white residue on skin and blocks a huge swath of UV rays. “If the U.S. is going to just approve one filter, this is a good one.” 

Will the U.S. approve more new sunscreen ingredients?

Andrews is skeptical that this potential new approval, if it happens, will open the floodgates of innovation. Nothing has fundamentally changed about how sunscreens are approved in the U.S.

“The pace at which the FDA has updated the requirements for sunscreens, and in particular, the ingredients allowed in sunscreens, is incredibly slow, to the point where we actually think that's detrimental to public health. But it's not all the FDA’s fault,” he says. “There's a large onus on these companies to test their ingredients in a way that ensures that they're not causing harm. So I'd say there's blame in multiple directions here, but ultimately, a breakdown that's not serving public interest.”

When might bemotrizinol hit the shelves?

Dobos suspects that the ingredient may be approved by summer 2026. Although that’s too early to be available in sunscreens this beach season, she’s still looking forward to hearing from the FDA on its decision. “It has always felt like Lucy and Charlie Brown, when she would pull the football away as he was going to kick it,” she says. “But this time feels different.”