Expert weighs in on sunscreen ingredients, application tips and precautions
18 July, 2022: People who use sunscreen regularly have lower risk of skin cancer and younger-looking skin, but with so many varieties on the market, it is important to choose one that works well, says an expert from global health system Cleveland Clinic.
Dermatologist Melissa Piliang, MD, says that daily use of sunscreen that is SPF 30 or higher can reduce the risk of skin cancer. In addition, individuals can slash their risk of melanoma, the deadliest form of skin cancer, by 50% as well as decreasing the risk of the most common skin cancer, squamous cell carcinoma, by 40%.
Dr. Piliang adds, “Aside from cancer, the sun's UV rays damage the skin and cause wrinkles, dark spots and sagging. Regular sunscreen use reduces and prevents these effects.”
One consideration when picking a sunscreen is whether it contains physical or chemical filters, or a combination of both. “Physical sunscreen ingredients work like a reflective barrier, scattering UV rays before they penetrate your skin. Chemical filters absorb UV rays, changing them into heat before they can damage the skin,” Dr. Piliang says.
“Choosing a physical or chemical sunscreen comes down to preference,” she adds. “People with sensitive skin may prefer physical sunscreens, as they tend to be less irritating for certain skin types. But physical sunscreens can sometimes leave a white cast. You may have to try different kinds until you find your favorite.”
Physical sunscreen ingredients — sometimes called mineral sunscreens — include titanium dioxide and zinc oxide. If the sunscreen contains chemical filters, the active ingredients may include avobenzone, homosalate, octocrylene, octinoxate, octisalate, and oxybenzone.
Another consideration is evaluating the safety and efficacy of the sunscreen ingredients, some of which are still being evaluated by bodies such as the U.S. Food and Drug Administration (FDA). The FDA is currently seeking more safety data on certain sunscreen ingredients before they can be listed as GRASE — “generally recognized as safe and effective,” a more stringent safety level. These ingredients include avobenzone, ensulizole, homosalate, octinoxate, octisalate, octocrylene, and oxybenzone.
“This does not mean these ingredients are unsafe or that individuals should avoid products where they are listed,” says Dr. Piliang points out, “It just means the FDA wants to be sure they have enough information before they can classify them as GRASE. If you want to be cautious, choose a sunscreen that contains zinc oxide or titanium dioxide, which both have the GRASE designation.”
Broad spectrum protection
Dr. Piliang also advises checking the sun protection factor (SPF) on the sunscreen label. “For days when you're outside for only short periods, you can get away with a minimum of SPF 15. But if you're going to be outside for more than a few minutes, choose at least SPF 30,” she says.
In addition, the type of protection offered needs to be considered. “Your skin is exposed to two types of UV rays: UVA and UVB,” says Dr. Piliang. “The SPF number tells you how much protection the sunscreen provides against UVB rays, which are the main cause of sunburn. But SPF doesn't tell you how much protection you're getting from UVA rays, which can cause skin damage and skin cancer.”
To ensure protection from UVA rays, Dr. Piliang advises choosing a sunscreen that lists “broad spectrum” on the label. This term means the product protects against UVA and UVB rays.
Lastly, it is important to check the expiration date on the sunscreen, Dr. Piliang says, as the protection offered will decrease over a period of time.
Dr. Piliang also has some advice on how to apply the sunscreen once selected. “Be generous as a skimpy application could cheat you out of the protection you need. Most adults need at least 30 grams of sunscreen, or about three tablespoons, to get enough protection on their face, neck, arms and legs.”
“The active ingredients in sunscreen need about 30 minutes to kick in, so give it time to work before going out,” says Dr. Piliang. “Reapply at least every two hours. And even if your sunscreen says it's waterproof, always reapply after swimming and toweling off.”
Dr. Piliang concludes with a word of caution, “Sunscreen should be a part of your routine anytime you go outside. But the sun's rays are powerful, so don't expect your sunscreen to do all the heavy lifting. No sunscreen can block all UV rays. Good sun protection should also include seeking shade, wearing a wide-brimmed hat and sunglasses and choosing clothing that has sun protection built in. Enjoy the sun — but be smart about how much exposure you're getting.”