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You may not have heard of homosalate before. Still, if you're using sunscreen every morning (insert obligatory reminder that daily SPF is a non-negotiable), there's a good chance that you're using the ingredient daily without even knowing it. Sunscreens fall into two camps: physical formulas (which rely on minerals such as zinc oxide and titanium dioxide to sit on top of the skin and deflect rays) and chemical formulas (which rely on chemical ingredients that penetrate the skin and absorb UV rays before they can cause damage). Homosalate is the main active in the latter, found in an array of chemical sunscreens. Ahead, dermatologist Eddie Fincher of Moy Fincher Chipps Facial Plastics and Dermatology, cosmetic chemist and founder of Perfect Image David Petrillo, and board-certified cosmetic dermatologist Shereene Idriss weigh in on everything you need to know about homosalate—including the controversy surrounding it.
Meet the Expert
- Eddie Fincher is a dermatologist of Moy Fincher Chipps Facial Plastics and Dermatology.
- David Petrillo is a cosmetic chemist and the founder of Perfect Image.
- Shereene Idriss is a board-certified cosmetic dermatologist.
Type of Ingredient: Chemical sunscreen
Main Benefits: Absorbs UV rays, specifically UVB rays, to ward off damage to the skin cells' DNA known to cause cancer, says Fincher.
Who Should Use It: Everyone should use sunscreen daily; however, those with sensitive skin or who are pregnant or breast-feeding may prefer to opt for mineral-based sunscreens.
How Often Can You Use It: If you're using a sunscreen with homosalate, it can, and should, be used daily and even reapplied every two hours for maximum protection.
Works Well With: It's always paired with other chemical sunscreens such as avobenzone, octinoxate, and octisalate to ensure complete, broad-spectrum UV coverage.
Don't Use With: There aren't any specific ingredients known to interact poorly with homosalate, but it (and other chemical sunscreens) can cause skin irritation for some.
What Is Homosalate?
"Homosalate is an organic compound belonging to a class of chemicals known as salicylates," explains Petrillo. It's a chemical sunscreen that shields the skin from sun exposure by absorbing UV light and converting it to heat so that it can't cause DNA damage to the skin cells, he adds. There are plenty of other chemical sunscreen ingredients, but homosalate is incredibly common. In fact, it's found in almost half of commercially-available sunscreens, notes Fincher.
Homosalate's mechanism of action—and that of any chemical sunscreen—depends on it being absorbed into the skin (unlike physical sunscreens, which sit on top of the skin). It's this absorption into the body that's incited talk about the safety of these ingredients.
Benefits of Homosalate for Skin
According to Petrillo, there isn't a huge difference between the various chemical sunscreen ingredients, all of which work the same way. The differences lay in terms of which specific UV rays they can absorb and protect against.
Homosalate, in particular, is a UVB-blocker, protecting against the UV damage that is known to cause skin cancer, says Fincher. To that point, "since it has very limited efficacy against UVA rays, it needs to be combined with other agents to ensure complete protection," adds Idriss. (She also notes that homosalate isn't particularly photostable and needs to be combined with other ingredients to keep it stable as well.) It's this combination of chemical sunscreen ingredients, some of which work against UVA rays and some of which work against UVB rays, that will offer a larger range of protection so that a sunscreen can be called "broad-spectrum," notes Fincher.
Side Effects of Homosalate
Skin irritations and/or allergic reactions to homosalate are the biggest side effect, says Fincher (the same goes for pretty much any chemical sunscreen ingredient). As a general rule of thumb, that's why mineral-based formulas are usually recommended for sensitive skin.
Otherwise, the big elephant in the room is whether or not homosalate and its counterparts are safe. You've likely seen buzzy headlines that link sunscreen usage to cancer, but according to the experts we spoke with, it's not quite that simple (or scary). The FDA is currently investigating homosalate and other active chemical sunscreen ingredients. Studies have shown that most of these chemicals are absorbed through the skin and can be detected in the blood, explains Fincher. However, he underscores that there aren't any studies in humans that have shown any adverse effects from this absorption. There's some concern about homosalate being an endocrine disruptor and affecting hormone production. However, these studies have all been done in vitro, and there's no definitive in vivo data, points out Idriss, who says further research is still needed.
How to Use It
Unsure if you should use homosalate, given all of that information? "We know for certain that these chemical ingredients are effective in preventing DNA damage and skin cancer, and there are no known adverse effects on humans," says Fincher. Sunscreens have been protecting us for a long time, and for now, the more immediate threat is UV rays and their ability to cause skin cancer, rather than the issues surrounding the ingredients, adds Petrillo. The bottom line: Any risk of using a chemical sunscreen is far less than that of using no sunscreen at all. But, if you are concerned, go ahead and pass on the homosalate and other chemical 'screens and opt for mineral formulas instead. Either way, make sure you're using a broad-spectrum formula with at least an SPF 30 and reapplying every two hours.
The Best Products With Homosalate
This is a go-to for Idriss, who lauds that it works well for all skin tones and has a beautifully lightweight finish that layers nicely under makeup. Credit a water-gel formula that makes it feel more akin to a serum than a goopy sunscreen, plus no greasy residue.
Always stressing about sunscreen causing breakouts? Try this one, on recommendation from Petrillo. It offers broad-spectrum protection without clogging pores since it's non-comedogenic and is both oil- and fragrance-free, he says. Bonus points for the matte finish, a boon for those with shiny skin.
Product minimalists will appreciate that this one bottle both acts as your daily moisturizer and delivers your daily dose of SPF. Petrillo is a fan, pointing out that the hydrating formula contains both ceramides and niacinamide to replenish the skin barrier. It's also fragrance- and paraben-free, and even sensitive skin-tested.
"This lightweight and elegant formulation goes on seamlessly," says Idriss, a choice pick for the sunscreen-haters out there. Despite its featherweight application, it still packs a powerful protective punch with broad-spectrum SPF 50 and, as a bonus, works equally well on both face and body.
People often forget that the lips need sunscreen, too; they're one of the most-often forgotten parts of the face, says Petrillo. He recommends this lip balm, which combines that oh-so-necessary, broad-spectrum SPF with rich moisturizers such as honey, shea butter, and sunflower seed oil.
According to Idriss, this body sunscreen does, in fact, live up to its name with a "non-greasy, beautifully matte finish." It's water-resistant for up to 80 minutes (a great pick for beach days) and contains protective antioxidants to ward off and undo sun-induced damage.
Just like the lips, the hands are also often neglected when it comes to sunscreen, yet, somewhat ironically, they are exposed to the sun pretty much all the time. Petrillo suggests using this hand cream; it pulls double-duty, both as a great moisturizer and a solid sunscreen.