The U.S. Food and Drug Administration approved bemotrizinol — sometimes called BEMT — in June. The first sunscreens containing it are now hitting U.S. store shelves, including formulas from Neutrogena and other manufacturers.

Dermatologists say the chemical fills an important market gap by offering broad protection, like the most well-established sunscreen ingredients, but without their cosmetic downsides, including white streaking.

BEMT has decades of safety data behind it, including studies showing it has minimal absorption into the skin. That’s been a concern with some older sun-blocking chemicals.

“It’s not a brand-new ingredient that you’re going to be the first person to try,” said Dr. Jennifer Stein, a dermatologist at NYU Langone Health.

Here’s what to know:

New ingredient offers broad protection without streaks

To be effective, sunscreens must protect against both forms of ultraviolet light that can damage the skin — UVB rays, which cause most sunburn, and UVA rays that pose the greatest risk of skin cancer and wrinkles.

Sunscreens that block both forms are labeled “broad spectrum protection.” Those that don’t must carry an FDA warning label.

BEMT is the first chemical-based sunscreen in the U.S. that offers this dual protection. Previously, manufacturers had to mix multiple ingredients to protect against both UVA and UVB light.

“This ingredient provides a solution for what is currently a big gap with respect to providing strong UVA protection,” said David Andrews, chief science officer of the Environmental Working Group, a nonprofit that advocates for higher sunscreen standards.

A different class of sunscreens, using minerals such as zinc oxide and titanium dioxide, has long been shown to offer strong protection against both forms of ultraviolet light. These mineral-based formulas work by physically blocking harmful rays from the skin.

But some people — particularly those with darker complexions — tend to avoid them because they cause white streaking and discoloration. In other cases, people don’t like their texture or consistency.

“Those are good sunscreens,” Stein said. “But for people who aren’t so inclined to use them — maybe they don’t like how it feels on their skin — this is a nice option.”

There’s less skin penetration with the new formula

The fact that chemical-based sunscreens are absorbed into the skin means they have to be carefully studied to make sure they aren’t building up in the body at unsafe levels.

Last month, the FDA revoked approval of an older chemical ingredient, oxybenzone, after determining it was “absorbed through the skin to a greater extent than previously understood.”

That’s not a problem with BEMT.

“It’s a molecule that’s too big to really penetrate through the skin and get absorbed into the bloodstream,” Stein said. “The older chemical sunscreens had small molecules.”

As part of its safety review, the FDA reviewed studies of BEMT in more than 500 patients conducted by Dutch manufacturer DSM Nutritional Products. Levels of the chemical absorbed into the skin were nearly undetectable, the studies found.

Agency reviewers said research in people who used the sunscreen daily for up to three weeks showed that BEMT “did not cause irritation” or allergic reactions. As a result, the FDA designated the ingredient as “generally recognized as safe and effective,” alongside the older mineral ingredients zinc oxide and titanium dioxide.

More than a dozen other ingredients are currently used in U.S. sunscreens, but the FDA has said they will require additional evidence to support their safety and effectiveness. The FDA review is part of an ongoing effort to overhaul U.S. sunscreen ingredients that kicked off in 2019.

More evidence is needed about the impact on coral reefs

Scientists have shown that some sunscreen ingredients can trigger bleaching and damage coral reefs. That’s led to bans on two chemical ingredients — oxybenzone, the ingredient recently targeted by the FDA, and octinoxate — in Hawaii and parts of Florida. It’s estimated about 25% of the sunscreen people apply to their skin washes off while swimming or wading in the ocean.

The U.S. government doesn’t classify the environmental impact of sunscreens, and marketing claims like “reef safe” or “reef friendly” have no standard definition or requirements. The European Union’s environmental agency has found “limited evidence of environmental toxicity” with BEMT, but longer-term research is needed.

Mineral ingredients like zinc oxide are generally considered safer for the environment, although some experts recommend staying away from so-called nano formulations. Those products are made with tiny particles that are more likely to be inhaled or absorbed by marine organisms.

Older chemicals were often unstable

Experts say BEMT has one other key advantage, in that it doesn’t quickly break down in the sun. That’s been a particular issue for avobenzone, the only other chemical-based ingredient that filters UVA light.

“Avobenzone has been known to be particularly unstable on its own, and a lot of work and reformulation efforts have gone into trying to find ways to stabilize it,” said Andrews. “BEMT is significantly more stable.”

As with all sunscreens, dermatologists say it’s important to reapply every few hours — more frequently if you’re swimming or sweating a lot.

Also, people shouldn’t rely on sunscreen alone when spending time outside, Stein said. Taking breaks in the shade, wearing a hat and sun-protective clothing are all important protections.

“Sunscreen is just one part of an overall sun-protection plan,” Stein said. “Clothing is even better.”

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