“Butyl octyl salicylate is a synthetic ingredient that helps improve the aesthetics and effectiveness of sunscreen products,” says cosmetic chemist Ron Robinson, founder of BeautyStat. “This is achieved by helping to dissolve and stabilize the active ingredients of the sunscreen, and also provides emollients. It also has the ability to absorb UV rays, which can help boost the product’s SPF even more.”

That’s why some call it an “SPF booster.” It helps to stabilize the sunscreen, improve its look and feel, and increase its ability to absorb UV radiation. It does the latter by absorbing UV light and triggering a chemical reaction that then turns the UV into heat.

If that sounds all right very Conventional chemical sunscreens—as opposed to physical filters that create a barrier to protect the vulnerable skin underneath—well, that’s because they’re pretty much the same. In fact, butyl octyl salicylate is “very similar in chemical structure to octisalate, which is an approved sunscreen in the U.S. and many other countries,” says product developer Emily Filen, Murad’s senior science manager.

“The official name for octisalate is ethylhexyl salicylate, which, as the name suggests, is a relative of butyl octyl salicylate,” writes cosmetic chemist Michelle Wong, Ph.D., on her Lab Muffin Beauty Science website. And the “salicylate” part is the component that actually absorbs UV light, which is the same in both molecules. “What’s different is actually not interacting with UV at all,” she adds.

So why isn’t it considered active SPF, you may ask? Well, sunscreen actives have to go through a very long and difficult process to become regulated by the FDA. I strongly suggest reading Wong’s full post, which dives deeper into the ins and outs of sunscreen regulation. But the bottom line is that there is a lot of legal red tape, and butyl octyl salicylate is still not registered for some reason.