sunscreen

Active outdoor people should look for the following on sunscreen product labels:

SPF rating: SPF = Sunburn Protection Factor. It’s a gauge of the product’s effectiveness against sunburn-causing ultraviolet B (UVB) rays. If you are outside for long stretches (2+ hours), choose SPF 30 or higher.

Broad spectrum: This indicates that a product is deemed effective against both UVB (skin-burning) and UVA (skin-aging) rays. UVA and UVB rays can also contribute to skin cancer, the most common cancer of all. If you see “broad spectrum” on a label, it’s a good thing.

Sweat- or water-resistant: No sunscreen is waterproof, even though that term used to appear on product labels. Based on performance in lab tests, new Food and Drug Administration (FDA) guidelines now allow products to claim water (or sweat) resistance of either 40 or 80 minutes.

Shop REI’s selection of sunscreen.

Chemical or Mineral Sunscreen?

Active ingredients in sunscreen are what protect skin from UV rays. They are listed near the top on the back label. Your choices are:

Chemical Mineral ("Natural" or "Physical")
Avobenzone, octocrylene, octinoxate,
et al.
Zinc oxide or titanium dioxide.
UV rays are absorbed (then released as a small amount of heat). UV rays are reflected (as if many tiny mirrors are spread on skin).
Used by millions for decades. Often preferred by people averse to chemicals or with sensitive skin.
May irritate some sensitive skin; some health questions are debated. Harder to apply; may leave white sheen.


Both types are approved for use by the FDA (which regulates sunscreen) and are endorsed by the American Academy of Dermatology.

SPF ratings apply only to sunburn-causing UVB rays. Which active ingredients are most effective against UVA?

Avobenzone (a chemical) and zinc oxide (a mineral) are both rated by the Environmental Protection Agency as providing “extensive” UVA protection. A notch lower, providing “considerable” UVA protection, are titanium dioxide (a mineral) and meradimate, sulisobenzone, dioxybenzone and oxybenzone (chemicals).

Some debate surrounds the long-term reliability of avobenzone and possible health consequences of oxybenzone. Part 3 of this series, Sunscreen: How It Works, offers more details.

Which Sunscreen Is Best?

No perfect sunscreen exists. “The best sunscreen is the sunscreen you like well enough that you’ll use it regularly,” says John E. Wolf, Jr., MD, MA and Professor and Chairman of the Department of Dermatology at the Baylor College of Medicine in Houston.

While UVB rays affect skin primarily between 10am and 2-4 pm, UVA rays (which can penetrate skin more deeply and cause it to age it without you feeling its effects) work on your skin during all daylight hours. Accordingly, Dr. Wolf tells REI that he applies a broad-spectrum SPF 30 (or higher) sunscreen to his exposed skin daily.

“A sunburn is the first acute thing you’re trying to prevent, then aging of the skin, then pre-cancers and skin cancers,” Dr. Wolf says. “The areas where we see the worst results of pre-aging and pre-cancers are the head, neck and the back of the hands. I recommend putting sunscreen on every day.”

For tips on sunscreen usage, see part 2 of this series, Sunscreen: When and How to Use.

Shop REI’s selection of sunscreen.

Sunscreen Quick Tips

Wary of chemicals? Try a mineral-based sunscreen, which contains either zinc oxide or titanium dioxide. Mineral formulas vary in how smoothly they spread on your skin (some can be tough to rub in) and how much of a white patina they leave on your skin (some show noticeably, some leave almost no trace).

Unafraid of chemicals? You have lots more choices and a broader range of prices.

Skin sensitivity or skin allergies? Your better sunscreen choice is likely to be a mineral sunscreen. You may also want to steer clear of formulas that include alcohol or fragrances.

Sunscreen SPF 50

When to choose SPF 50 or 50+. Use high SPF sunscreens on thin-skinned areas such as your nose, ears and backs of hands. It’s also a good to use on any exposed skin when exploring at high altitude, polar regions or areas of intense sun exposure (including reflective surfaces such as snow). Some users feel SPF 50 sunscreens feel heavier, greasier or less breathable on skin. They use SPF 30 or higher on sweat zones (arms and legs) and carry a separate tube of SPF 50 or 50+ to touch up thin-skinned areas.

What about that SPF 100 sunscreen at the drug store? That’s sheer marketing bluster. Don’t be fooled. SPF 15 sunscreen blocks 93% of UVB rays, SPF 30 blocks 97%. You’re not doubling your protection with the twice-as-high number. SPF 50 blocks 98%. No sunscreen can block 100% of solar energy. So any product labeled higher than SPF 50+ offers only a minuscule fraction of additional protection beyond 98%.

Kids. Use only shade to protect kids under 6 months of age because their skin can too easily absorb sunscreen. Adult sunscreen is fine to use on kids 6 months and older. Be vigilant to protect skin from excessive sun exposure. Bad sunburns early in life have been cited as contributors to cases of adult skin cancer.

Sunscreen sprays. Kids often favor sprays, though much can be wasted if kids are allowed to spray their skin wildly. Anyone using a spray, child or adult, should avoid inhaling the mist. What if all you have is a spray and your face (or your child’s face) needs protection? Spritz your hand with the spray sunscreen and rub it in. Sprays can be good for hairy adult bodies and hatless adults with bald spots or thinning hair.

Coral reefs. A study reported by National Geographic in 2008 indicated that some chemical sunscreen ingredients may bleach coral reefs. The study’s primary researcher suggested that swimmers or divers exploring coral reefs choose mineral (nonchemical) sunscreens.

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Why Bother with Sunscreen?

Prolonged sun exposure leaves skin vulnerable to aging (wrinkles), burning and skin cancer.

Skin cancer is a serious issue. The Environmental Protection Agency reports:

  • Skin cancer is the most common form of cancer in the United States.
  • More new cases of skin cancer are diagnosed each year in the U.S. than new cases of breast, prostate, lung and colon cancer combined.
  • One of 5 Americans will develop skin cancer in their lifetime.

In Australia, the depletion of the Southern Hemisphere’s ozone layer leaves Australians especially vulnerable to skin cancers such as melanoma.

“A sunburn is the first acute thing you’re trying to prevent, then aging of the skin, then pre-cancers and skin cancers,” Dr. Wolf says. “The areas where we see the worst results of pre-aging and pre-cancers are the head, neck and the back of the hands. I recommend putting sunscreen on every day."

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Article contributors: Brian Adams, MD, MPH and Interim Chairman of the Department of Dermatology at the University of Cincinnati School of Medicine; Robert Friedman, Clinical Professor of Dermatology at the New York University School of Medicine; Susan M. Swetter, MD, Professor of Dermatology and Director of the Pigmented Lesion and Melanoma Program at Stanford University Medical Center; John E. Wolf, Jr., MD, MA and Professor and Chairman of the Department of Dermatology at the Baylor College of Medicine in Houston.