For the first time in nearly three decades, the Food and Drug Administration approved a new chemical UV filter for use in sunscreens sold in the U.S. And that has many dermatologists cheering.

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The new ingredient is called bemotrizinol, and it has several advantages over the chemical sunscreen ingredients previously available in the U.S., Rogers says.

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In general, chemical sunscreens sold in the U.S. rely on an ingredient called avobenzone to block out UVA rays, says Kelly Dobos, a cosmetic chemist who teaches at the University of Cincinnati.

But avobenzone by itself isn't photo stable, meaning its protection can start to break down rapidly when exposed to sunlight. And as avobenzone breaks down, it can release molecules that lead to skin irritation, says Alexa Friedman, a senior scientist with the nonprofit Environmental Working Group, or EWG.

By contrast, bemotrizinol offers protection against both UVA and UVB rays all on its own, and it is photo stable, so it breaks down more slowly, offering better protection, Rogers says.

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Bemotrizinol has been widely used in European and Asian sunscreens for decades. But it has taken 20 years for the FDA to approve its use in this country.

That's because in the U.S., sunscreens are regulated as over-the-counter drugs rather than cosmetics, as they're classified in Europe. That means ingredients need to undergo rigorous testing for safety and efficacy before they can be approved for use in the U.S.

"It's really expensive and time consuming," Dobos says. The European company DSM-Firmenich spent at least $18 million over more than two decades in its push to gain FDA approval for bemotrizinol.

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However, all that testing means bemotrizinol has more safety data to back it up than any other chemical sunscreen ingredient currently approved in the U.S., says Friedman of EWG.

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Until now, Rogers says, the only sunscreen ingredient available in the U.S. that offered the aforementioned advantages of bemotrizinol – photo stable, non-irritating, minimally absorbed into the skin and with good broad spectrum protection against both UVA and UVB rays – was zinc oxide.

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Bemotrizinol, on the other hand, is transparent on the skin, and because it protects against both UVA and UVB rays on its own, it doesn't have to be mixed with as many other chemical filters and stabilizers to achieve broad spectrum protection, Dobos adds. She says that should lead to more aesthetically pleasing, less greasy sunscreen formulations in the near future.