Sunscreen Primer

What you need to know to have a burn-free summer.
By Lindsey Galloway

Choosing the best sunscreen can be tougher than finding the perfect swimsuit. With hundreds of options available, should you reach for a product labeled “nano-free,” “all-day protection,” or “SPF 700”? Plus, terms like SPF, UVA, and UVB can have you swimming in a sea of acronyms before you even hit the water. We break it all down to help you pick the most effective sunscreens for summer.

Understanding the acronyms
The most familiar sunscreen term, SPF, or sun protection factor, is designated according to how long it would take you to burn (or develop some redness) without protection versus how long you could stay burn-free while wearing sunscreen. But SPF measures only protection from burn-causing ultraviolet B (UVB) light, not from longer-wavelength ultraviolet A (UVA) rays, which “penetrate the skin much deeper than UVB, causing wrinkles and skin cancer,” explains Susan O’Malley, MD, a cosmetic physician in Madison, Connecticut. “Think B for burning and A for aging.”

Most experts recommend at least SPF 15, which means it takes 15 times longer for UVB light to cause redness than if you didn’t wear sunscreen. But a higher SPF doesn’t mean exponentially more protection, as many assume. SPF 30 blocks just 5 percent more UVB light than SPF 15—rather than twice as much—and no sunscreen, regardless of SPF, retains its efficacy after two hours. Still, if you tend to burn quickly or have fair skin, go with SPF 30, but any SPF over 50 is basically gratuitous, according to the FDA.

Mineral versus chemical
To protect yourself from both UVB and UVA rays, choose an all-natural mineral sunscreen made with a concentration of at least 7 percent zinc oxide or titanium dioxide—or a combination of the two, recommends Sonya Lunder, senior analyst at the Environmental Working Group (EWG). Unlike chemical lotions that absorb UVB rays before they do damage, mineral sunscreens physically block and reflect sunlight. Rub about 1 teaspoon onto your face and 1 ounce (enough to fill your palm) all over your body 30 minutes before going outside; reapply every two hours or immediately after swimming and sweaty activities.

Unfortunately, mineral sunscreens can leave a chalky white residue on your skin, which has made spreadable, absorbable, synthetic lotions and creams popular. However, non-mineral sunscreens contain active chemical ingredients like oxybenzone, octisalate, and octinoxate, which—besides the fact that they don’t block the harmful UVA rays—raise many health concerns.

Oxybenzone (or benzophenone-3), found in most drugstore sunscreens, is particularly troubling. Studies have linked high oxybenzone levels to low birth-weight babies and altered hormone levels, and the chemical has been shown to generate free radicals following exposure to sunlight. Scary, because the body easily absorbs oxybenzone: The Centers for Disease Control and Prevention found traces in more than 97 percent of 2,500 human urine samples tested in 2008.

What about nanos?
Some sunscreen manufacturers smash zinc oxide and titanium dioxide into super-tiny particles, called nanoparticles, which may provide superior sun protection—and cut down on chalky white residue. “Think of it as throwing a bunch of white marbles on a red carpet versus pouring sand on it,” explains Bob Root, cofounder of Keys Soap, which uses nano-sized zinc in its SPF 30 sunscreen. “You’ll still see the red underneath the marbles, but the sand can cover it completely.”

But public-health watchdog organizations like the EWG haven’t given nanoparticles the green light—yet—fearing they may penetrate the skin and damage cells. Although most studies on humans have disproved this concern thus far, research on hairless mice showed skin damage, decreased collagen, and lower body weight following exposure to titanium dioxide nanoparticles. Lab studies also show that nanoparticles create more skin-damaging free radicals than do their normal-size counterparts. However, because this oxidative damage is minimal compared to that caused by UV radiation on bare skin, the EWG announced in 2009 that any sunscreen with zinc oxide or titanium dioxide, whether or not it includes nanoparticles, is better than wearing no protection—and still safer than super-absorbing chemical sunscreens.

Still, to be on the safe side, you can choose a mineral-based sunscreen that does not include nanoparticles. Cruise the EWG’s Skin Deep cosmetic database ( for a list of options, and see our clean picks in “Screened for Your Protection”.

Screened for Your Protection
Marie Veronique Organics

Moisturizing Face Screen, SPF 30–No Tint. Jojoba, sea buckthorn, apricot kernel, and red raspberry seed oils add antioxidant punch to this 24 percent zinc oxide face cream. $40, 2 oz;

Lotus Moon
Sol Reflect SPF 25. Contains 10 percent titanium dioxide and 2 percent zinc oxide, with green tea extract and shea butter to keep skin smooth. $36, 4 oz;

Soléo Organics
All Natural Sunscreen. Not only is your skin protected with the power of zinc oxide and healing oils, the 100 percent recycled packaging looks out for the health of the environment as well. $30, 5.3 oz;

Kabana Skin Care Green Screen
Organic SPF 20 Sunscreen. Eight simple ingredients, including 25 percent zinc oxide, make this great sun protection for the whole family. $16, 4 oz;

Goddess Garden
Natural Sunscreen SPF 30. This zinc oxide–titanium dioxide blend barely leaves any white residue. $13, 3 oz;

Jane Iredale
Powder Me SPF 30.
It may look like makeup, but this loose powder is a dry titanium dioxide sunscreen you can blot on your face anytime. $44, 0.7 oz;