Everything You Need to Know About Zinc Oxide and Your Sunscreen
You may have seen the ingredient “zinc oxide” on everything from your sunscreen bottles and calamine lotions to makeup products and even acne treatments, but do you really know what it really is—or does? Technically, it is all-natural, occurring as the mineral zincite, but it can also be produced synthetically or through chemical processing by human agency. Its most common and notable use is as a sunscreen agent, which it is FDA-approved for.
“As a mineral-based sunscreen active ingredient, zinc oxide reflects light off the surface of the skin where the sunscreen is applied back into the environment, much like a mirror,” says Melanie D. Palm, M.D., San Diego–based dermatologist, cosmetic surgeon and founding director of Art of Skin MD.
“Zinc oxide can be ‘micronized,’ meaning it’s processed into very small particles, so small that the preparation appears clear when applied on the skin.” Non-micronized formulations, she explains, are often less cosmetically elegant and are more opaque or white. So, if you’ve ever applied a sunscreen that left a white, powdery cast on your body, it most likely contained zinc oxide as a key ingredient.
To help you further understand how this mineral plays a key role in your skin care regimen, especially in the sun-protection department, here are some commonly asked questions answered by top dermatologists.
How does zinc oxide work compared to other sunscreen ingredients—and is it safe?
Zinc oxide isn’t the only sunscreen ingredient used to block harmful UVA and UVB rays. Many sunscreens contain an ingredient called titanium dioxide, which, like zinc oxide, is typically found in mineral sunscreens. It’s also considered safe since it does not penetrate the skin and offers broad-spectrum protection against both UVA and UVB rays. Although, Francesca Fusco, M.D., dermatologist at Wexler Dermatology in New York City, points out that some studies have shown that titanium dioxide can work as a photosensitizer that can be absorbed by the skin. “A safe bet is to look for sunscreens that are known to use particles too big to be absorbed, or those containing zinc oxide, which is the safest ingredient according to the Environmental Working Group (EWG).”
Still, all four common sunscreen ingredients—mineral-based zinc oxide and titanium oxide and chemical-based avobenzone and mexoryl SX (ecamsule)—have been shown to be non-toxic when used on the skin and to not break down when exposed to the sun, which is vital. “Titanium and zinc oxides are the best options on this list as they both block and protect against all UVA rays, whereas the other two don’t provide as much protection,” adds Dr. Fusco.
Article by Jenn Sinrich