Sunscreen is both life-saving and face-saving. Just take a glance at the parts of you that never see the light of day, and you’ll see what I mean. But sunscreens are relatively new technology. For instance, the FDA only released testing standards for sunscreen manufacturers, clearly defining labels like “broad spectrum protection,” in 2011. And we still don’t completely know what the effects of letting those active ingredients soak through the skin and enter the bloodstream might be, Scientific American reports.

While research has shown that some of the nanoparticles in sunscreen (like zinc) are fine, studies suggest that some chemical UV filters might be linked to hormone disruption, and dermatologists are experimenting with new forms of sun protection. A study in Nature Materials suggests that a coating that stays on top of the skin, rather than soaking in, might be a good alternative.

The Yale University–created sunscreen is created with bioadhesive nanoparticles that cling to the proteins on skin cells. It’s water-resistant, only coming off with a vigorous bout of toweling off. In trials with mice, the skin-cell–bound protection worked just as well as traditional sunscreen to block UV rays, the study found, with just a tiny fraction of the concentration of chemical UV filters.

However, you probably won’t be slapping this on at the beach anytime soon. The FDA hasn’t approved any new sunscreen ingredients since 1999—even as other countries have implemented more effective sunscreens—due to a bureaucratic logjam at the FDA. Since there haven't even been trials with humans yet, it'll be a long time until this new type of sun protection even makes it to the final stages of FDA review, much less to stores. In the meantime, we’ll have to make do with the best sunscreens on the market right now.

[h/t Scientific American]

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