How to Buy the Best Sunscreen for You

— -- intro:Choosing a sunscreen used to be a numbers game: You'd go for a relatively high SPF (at least 30!) and slather it on. Turns out, there's a lot more to consider to keep your skin safe from the sun and looking young, too. "What you really need to focus on is tailoring the kind of sunscreen to what you're doing outdoors," says Joshua Zeichner, MD, director of cosmetic and clinical research in dermatology at Mount Sinai Hospital in New York City. "If you're not choosing your product based on your activity, you put yourself at risk of sunburn and serious skin damage.

Happily, the latest sunscreen options are more of a no-brainer to use than ever. "Scientists have come up with formulations that absorb into skin more easily, last longer and protect you from more than just UV rays," says Marie Jhin, MD, a dermatologist in San Francisco. Health consulted the experts to find the best products and pointers to protect you all day, every ray.

Hey, what are 'IR' rays?

Just when you thought you had UVA and UVB figured out, there's buzz about infrared radiation, which can also speed aging. While UV rays make up about 7 percent of solar light, the IR kind (which we mainly experience as heat from the sun) comprise a whopping 53 percent. Scientists once believed that these rays were fully absorbed by the ozone layer, but now they're less sure, Dr. Zeichner says, given the ozone's slow but steady depletion. Expect more products that protect against UV and IR rays, like SkinMedica Total Defense + Repair ($75; skinmedica.com).

15 Biggest Sunscreen Mistakes You're Making

quicklist: 1category: title:Beach daysurl:text:Your sun situation: You may not step foot on the sand without your trusty sunscreen, but—newsflash—you probably need much more protection than you're actually getting.

Your shield: A high-SPF chemical block. Look for ones with avobenzone, which is the only chemical that absorbs the whole UVA spectrum. A spray version, such as L'Oréal Paris Advanced Suncare Invisible Protect Alcohol-Free Clear Finish Spray SPF 50 ($8; amazon.com), is easiest to apply and—this is key—reapply throughout your beach day.

Protection pointers: "Often half your protection floats away with the breeze," notes Adam Friedman, MD, a dermatologist in New York City. "So hold the bottle an inch or two away from your skin, spray for roughly two seconds per area, then rub it in." Get your partner or a friend to do your back. For ultimate sun safety, pack a beach umbrella. "While you still receive some indirect light," Dr. Jhin says, "an umbrella provides protection against the hard-hitting UV light."

quicklist: 2category: title:Outdoor sportsurl:text:Your sun situation: Whether it's tennis or beach volleyball, you need products that last through your playtime and perspiration.

Your shield: A broad-spectrum, water-resistant lotion. Go for chemical formulas, which form a film on skin that absorbs UV radiation before it can cause any damage, recommends Leslie Baumann, MD, a dermatologist in Miami. Ones made with avobenzone or oxybenzone won't clump and compromise protection as you perspire, Dr. Zeichner says. Neutrogena CoolDry Sport Lotion SPF 70 ($9; amazon.com) penetrates skin in a mesh pattern to ensure that pores can breathe and sweat, while keeping UV rays at bay.

Protection pointers: Apply product at least 20 minutes before stepping out into the sun, since chemical sunscreens take that much time to absorb into the skin. "Reapply at least every two hours and after toweling or rinsing off," Dr. Friedman advises. "And note that those 'water-resistant' labels that promise 40 to 80 minutes of protection apply to sweating as well." If your skin is sensitive, Dr. Friedman adds, "look for a formula that contains multiple UV filters so that the concentration of each is lower, lessening the potential for irritation." For example, choose one that lists 2 to 3 percent of each active ingredient rather than 10 percent of one type.

Watch the video: 3 Tips for Applying Sunscreen

quicklist: 3category: title:Water-resistant SPF alerturl:text:Water-resistant sunscreens can be less effective in chlorine pools than in sea salt water, finds new research published in the International Journal of Cosmetic Science. That's because chemicals in chlorinated water can disintegrate essential ingredients. Your new pool rules: Reapply after every swim stint, making sure to first towel off completely.

quicklist: 4category: title:Commutingurl:text:Your sun situation: Twenty minutes on the bus or in the car, 10 minutes walking to the office, enjoying lunch outside—it all adds up. "Whether you get 30 minutes of sun every day for a month or sunbathe for an entire day, your skin suffers the same amount of damage—it's cumulative," says Rachel E. Herschenfeld, MD, a dermatologist at Newton-Wellesley Hospital in Newton, Mass. Oh, and FYI: If your office has a window, you're getting exposed to UVA light all day long—yet another reason to slather on sunscreen daily.

Your shield: A serum with SPF to wear under makeup; incorporate it into your morning routine and you'll never leave home unprotected. We like the lightweight, hydrating feel of La Roche-Posay Anthelios AOX Daily Antioxidant Serum with SPF ($35; amazon.com).

Protection pointers: Don't do just your face; apply the formula on your neck, too, including the sides and back. Then smear some all over your upper chest. On days when you're zipping around in your car for client meetings or taking a long walk during lunchtime, touch up with an easy-to-apply mineral sunscreen powder. Dr. Jhin recommends Colorescience Sunforgettable Mineral Sunscreen Brush SPF 50 ($64; colorescience.com).

quicklist: 5category: title:Weekend funurl:text:Your sun situation: Strolling through the farmers market, walking your dog or pushing your kids on the swing means you're getting direct sunlight without expecting it—or realizing it.

Your shield: An SPF stick with the physical blockers zinc oxide or titanium dioxide. Both provide instant protection since they sit on the skin rather than penetrate it like chemical filters, Dr. Herschenfeld says. Yes to Cucumbers Natural Sunscreen SPF 30 Stick ($8; amazon.com) is a cinch for tricky spots like your ears, hairline—even toes.

Protection pointers: "With sticks, you need to apply four passes—back and forth and back and forth—to get effective protection," Dr. Zeichner says. And don't forget your lips, paying special attention to your lower lip, which new research shows is 12 times more likely to be affected by skin cancer.

Beat 16 Summer Health Hazards

quicklist: 6category: title:Vacationurl:text:Your sun situation: You're rarely a rays person, except for those precious seven days of vacay. Going from 0 to 60 in the sun demands serious protection—the kind used by surfers and lifeguards, minus the white strip of zinc down your nose (although that works if you're willing, Dr. Herschenfeld says).

Your shield: A heavy-duty block that's high on SPF. "Look for the mineral UV filters zinc oxide and titanium dioxide—because they're big molecules, they sit atop skin and last longer," Dr. Friedman says. We like Shade SPF 30+ Opaque ($28; amazon.com), which was created by surfers. You can apply this type of block the second you're in the sun, so it's perfect for impromptu beach excursions, whale watches or just strolls on the boardwalk.

Protection pointers: Use two coats of sunscreen, Dr. Zeichner says: Apply one, let it dry, then layer on another. Also consider starting an oral OTC antioxidant containing polypodium leucotomos, like Heliocare ($30; walgreens.com), the week before your trip, Dr. Friedman suggests. Research shows it can offer an SPF of about 5 to 8, in addition to your sunscreen. Why not? Any extra protection is a great thing.

quicklist: 7category: title:A new way to undo sun damageurl:text:UV damage releases free radicals in your body that attack DNA structure, hinder the function of skin cells and cause mutations that may lead to cancer. Enter skin-care products with DNA-repair enzymes. "They can help reverse the effects of UV exposure by strengthening DNA, potentially preventing skin cancer and undoing signs of UV-related aging, like wrinkles and discoloration," Dr. Jhin says. A recent study in the Lancet found a 68 percent decrease in the development of actinic keratosis—the most common skin precancer—and a 30 percent drop of basal cell carcinomas in patients predisposed to skin cancer who were treated with a DNA-repair enzyme cream. Try Neova Damage Control Everyday Broad-Spectrum SPF 44 ($24; amazon.com).

quicklist: 8category: title:Skin cancer is color blindurl:text:Darker skin tones contain more melanin, the pigment that gives skin its color and protects against the sun. But new research in the Journal of the American Academy of Dermatology shows that those with darker skin need to be more vigilant about sun protection than they are. Consider this: The five-year survival rate for African-Americans with melanoma is 78 percent, significantly lower than that of Caucasians (92 percent), yet one study shows that 62 percent of African-Americans have never worn sunscreen. Says Dr. Baumann, "Anyone can get skin cancer, so skin tone is no reason to skip sunscreen."

This article originally appeared on Health.com.