Why your skin needs sunscreen all year long

That’s a mistake. “Sun damage is cumulative,” says Henry Lim, a dermatologist at Henry Ford Health in Detroit. “If you continue to expose your skin to the sun’s ultraviolet rays, the damage will continue — no matter what age you are.”

Taking action now can help protect your skin from further harm and possibly even reverse some damage. The first step: finding an effective sunscreen, one you don’t mind wearing every day.

How the sun ages your skin

Most of the skin changes we see as we get older don’t come from the aging process but from the sun’s UV rays. That’s true for all skin tones, though changes tend to occur earlier in those with light skin.

UVA rays penetrate the skin’s deeper layers, damaging the collagen and elastin that keep skin looking young and smooth. That results in wrinkles, brown spots, sagging and other signs of aging. UVB rays, which affect the outer layer of skin, cause sunburn. Both types alter DNA in the skin cells, which can trigger changes that can lead to skin cancer.

Fortunately, no matter your age or the extent of damage you’ve accrued, “it’s still not a lost cause,” says Karen Connolly, a dermatologist at the Memorial Sloan Kettering Cancer Center in Basking Ridge, N.J. “Start doing a better job with sun protection now and you may still slow down the rate at which your skin ages.”

You might also be able to turn back time a bit. “Even if you have a few wrinkles and dark spots, some of that may be reversed from regular use of sunscreen,” Connolly says.

Your risk of skin cancer

Of course, it’s not just about how your skin looks: Shielding yourself from the sun also helps prevent skin cancer. Rates steadily increase with age. Of the 149 people with a history of skin cancer in CR’s survey, 58 percent were diagnosed at age 55 or older.

Basal cell carcinoma, the most common type of skin cancer, rarely affects anyone under 40 and is most common in those 70 and older. Rates of squamous cell carcinoma reach their highest levels in those ages 70 to 79. The risk for melanoma, which can be deadly, rises in adults with each decade, peaking in people in their 80s.

Sun exposure early in life contributes to your risk, but skin cancers “require multiple mutations to arise in the skin cells’ DNA,” says Paul Nghiem, a dermatologist at the Fred Hutchinson Cancer Center in Seattle. “When you continue to expose your skin to UV rays, they act like fertilizer for any existing damage, making the cells grow more mutations. With age, the repair process slows down and more mutations stick around.”

The immune system also becomes less robust as you get older, which can contribute to the risk of developing skin cancer. “Sun exposure suppresses the skin’s immune system,” Lim says. “And if it’s not able to mount a strong response, it’s less able to repair DNA damage.”

Best strategies for sun protection

Staying in the shade, covering up with clothing and wearing a hat will help shield your skin from the sun. Any exposed skin should be covered with sunscreen, and you should use it every day. Here are some other important tips:

Pick the right sunscreen. A high-quality sunscreen has an SPF of at least 30. (SPF reflects how well a sunscreen protects against UVB rays.) It should also be broad-spectrum, meaning it shields against both UVA and UVB.

But you can’t just go by the label. Consumer Reports testing over the years has shown that the protection offered by a sunscreen doesn’t always match the SPF listed on the package. So if you can’t find a CR-recommended sunscreen (membership required), buy one that has an SPF of at least 50. Even that doesn’t guarantee adequate protection, our tests have found, but any sunscreen is better than none.

Choose a ‘chemical’ sunscreen. Sunscreens that use chemical UV filters, such as avobenzone or octocrylene, have done best in tests by Consumer Reports. These work by absorbing into the skin and soaking up UV rays. Mineral sunscreens — those with only zinc oxide, titanium dioxide or both — sit on the skin’s surface and deflect UV rays.

Some people prefer mineral sunscreens because chemicals irritate their skin or they’re concerned by reports indicating that some of those ingredients may harm the environment or pose health risks. But our tests have found that mineral sunscreens “consistently fall in the middle of the pack or lower in our ratings,” says Susan Booth, who oversees CR’s sunscreen testing.

It’s important to balance concerns you might have about chemical sunscreens with their known benefits. “We don’t have conclusive evidence that any sunscreen ingredients are causing harm,” Lim at Henry Ford Health says, “but we do know that unprotected sun exposure can lead to skin cancer.”

If you want to play it extra safe, avoid chemical sunscreens with oxybenzone or octinoxate, the two ingredients that have raised the most concern.

If you prefer a mineral sunscreen, choose one that was found by CR tests to have at least an SPF 15 and that got high marks for UVA protection, such as Badger Active Mineral Cream SPF 30 Unscented or Blue Lizard Sport Mineral Spray SPF 50-Plus Unscented. Diligently reapplying is especially important with mineral sunscreens.

Cover up. You can minimize the amount of sunscreen you need by wearing a rash guard instead of a bathing suit, or other clothing that shields your skin. You can opt for UPF (ultraviolet protection factor) clothing, but previous CR tests found that items made with polyester, spandex or tightly woven cotton without a UPF claim on the label were similarly effective.

Apply it right. For lotions, use a teaspoon-size dollop on your face and neck and — depending on what you’re wearing — one for your torso, one for your back, and one for each of your arms and legs. For a spray, hold it close to your skin, spray until the skin glistens and then rub it in. Reapply sunscreen every two hours or right after swimming or sweating.

Consumer Reports is an independent, nonprofit organization that works side by side with consumers to create a fairer, safer and healthier world. CR does not endorse products or services, and does not accept advertising. Read more at ConsumerReports.org.