Whether your skin care routine is simple or elaborate, there’s one product you should never skip: sunscreen. But with thousands of sunscreens on the market today, how do you choose the right one?
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Dermatologist Melissa Piliang, MD, provides advice on choosing a sunscreen that works — and how to avoid ones that don’t.
What does sunscreen do?
Sunscreen uses active ingredients to filter ultraviolet (UV) rays before they reach your skin. UV rays — which come from the sun and tanning beds — can cause skin cancer and extra signs of aging.
Sunscreen comes in gels, creams, powders and sprays that you apply directly to your skin. People who use sunscreen regularly have:
- Lower risk of skin cancer: Skin cancer is the most common cancer in the U.S. Daily use of sunscreen that is SPF 15 or higher can reduce your risk of skin cancer. You can slash your risk of melanoma, the deadliest form of skin cancer, by 50%. And you can decrease the risk of the most common skin cancer, squamous cell carcinoma, by 40%.
- Younger-looking skin: “The sun’s UV rays damage the skin and cause wrinkles, dark spots and sagging,” says Dr. Piliang. “Regular sunscreen use reduces and prevents these effects.”
How does sunscreen work?
The U.S. Food and Drug Administration (FDA) regulates sunscreens to ensure they’re safe and effective. “All FDA-approved sunscreens contain approved physical or chemical blockers or a mix of the two,” says Dr. Piliang.
Check the active ingredients on your sunscreen label to find out whether your sunscreen contains physical or chemical filters. Physical sunscreen ingredients — sometimes called mineral sunscreens — include:
- Titanium dioxide.
- Zinc oxide.
If your sunscreen contains chemical filters, the active ingredients may include:
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.
“Choosing a physical or chemical sunscreen comes down to preference,” says Dr. Piliang. “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.”
Understanding sunscreen SPF numbers
Sunscreen has a sun protection factor (SPF) number on the label. This number is important, but it’s not the only thing to look for.
“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 you’re protected from UVA rays, choose a sunscreen that lists “broad spectrum” on the label. This term means the product protects against UVA and UVB rays.
When you apply sunscreen, be generous. A skimpy application could cheat you out of the protection you need. “Most adults need at least one ounce of sunscreen, or about the size of a shot glass, to get enough protection on their face, neck, arms and legs,” says Dr. Piliang. “Use about a nickel-sized dollop for just your face.”
How long does sunscreen last?
Even if you slather on a large amount of sunscreen, it eventually breaks down and rubs off. The key is to apply early and often for the best protection.
“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.”
What’s the minimum SPF you should use?
Should you always choose a high SPF? It depends on what you’re doing that day.
“For days when you’re outside for only short periods, you can get away with a minimum of SPF 15,” says Dr. Piliang. “But if you’re going to be outside for more than a few minutes, choose at least SPF 30.”
Remember to check the expiration date on your sunscreen, too. A bottle that has spent multiple summers baking in the sun doesn’t offer the same protection it once did.
Sunscreen ingredients to avoid
If you’re using an FDA-approved sunscreen that’s sold legally in the U.S., your sunscreen is considered safe to use.
However, 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.
The ingredients in question include:
This doesn’t mean these ingredients are unsafe or that you should avoid products where they’re listed, notes Dr. Piliang. 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,” says Dr. Piliang.
Sunscreen alone isn’t enough
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,” says Dr. Piliang. “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.”
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