The argument that chemical sunscreens are unsafe gets even more muddled when the booster being used instead is structurally similar to an FDA-approved sunscreen filter. These types of ingredients are called analogs, Palermo explains. Take butyloctyl salicylate, a commonly used SPF booster that’s an analog for approved chemical UV filter octisalate. While they might function similarly, butyloctyl salicylate has not been formally petitioned for recognition as a sunscreen active by the FDA, Dobos says, so it is simply not acknowledged as such—even if it is working in the same way a similar, approved filter would.
“If chemical filters are ‘unsafe,’ why use an analog?” Palermo asks. “Either you don’t understand sunscreen—which begs the question, why are you making sunscreen?—or the brand is okay with misleading their community for a sale.”
There is, however, also some concern about the concentrations being used. For example, in the U.S., it’s illegal to sell a sunscreen with more than 5% octisalate due in part to potential environmental damage when worn in the ocean, Palermo says, but perfectly legal for a formula to have 10% butyloctyl salicylate—which, if you recall, functions similarly.
“Sunscreen boosters haven’t been subjected to the gauntlet of safety testing that [FDA-approved UV filters] are currently subject to,” Dobos says. “While these boosting ingredients may be safe as currently used, we just don’t have the same amount of data.”
In the same way there’s no conclusive data to say chemical sunscreen formulas are inherently more toxic than mineral ones, there’s no conclusive data to say SPF boosters are inherently safe or unsafe.
What should we do about this?
The good news is, unless you’re actively allergic to chemical sunscreen filters, there’s really no need to worry about sunscreen doping from a health perspective. Just know that despite 100% mineral claims, you might, in fact, be using a chemical-mineral hybrid sunscreen—which are fairly common in regions like Europe and Asia that are known for having far more cosmetically elegant SPF formulations than what we can purchase here in the U.S.
There are, however, a few tools you can use if you’re looking for more information surrounding sunscreens and SPF boosters.
Dieux’s Sun-Screener tool is “made to help people understand their sunscreens through education, not fear,” Palermo says. (FWIW, Dieux’s current product lineup doesn’t currently include sunscreen.) . All you have to do is copy and paste your sunscreen’s ingredient list (which you should be able to easily find on the packaging or brand website) into the Sun-Screener page, and it’ll break down the active UV filters and UV boosters, if any, in the formula. Further down on the same page, the brand has created a glossary that explains down the types of ingredients typically found in sunscreens, as well as a host of blog posts going deeper into more-specific sun-care related topics.
Meanwhile, Dobos encourages people to seek sunscreen information from trusted, science-backed sources like the Skin Cancer Foundation and the American Academy of Dermatology, both of which say the best sunscreen is the one you’re most likely to use—be it mineral or chemical—so long as it is SPF 30 or higher.
And, of course, Dr. Hartman says you can always bring your sunscreen to a board-certified dermatologist for guidance on what is in the formula and if it’s suitable for your particular needs. Remember, at the end of the day, sunscreen has proven to be the single most important step of any skin-care routine, and effective sunscreen of any kind—no matter the approved UV filter or added boosters—is always better than no sunscreen at all.
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