The Biggest Sunscreen Myths

Using Sunscreen Correctly Will Help Prevent Skin Cancer

mother applying sunscreen to son's back
AydAn Mutlu / Getty Images

Sunscreen isn't a panacea for preventing skin cancer, but it is an easy way to reduce your risk. Unfortunately, according to a 2013 survey, most Americans don’t use sunscreen. Making matters worse, there are many misconceptions about sunscreen that reduce its effectiveness. Here are some common myths.

SPF 90+ Sunscreens Are Better Than SPF 30 Sunscreens

Not much. Ultra-high SPF claims are mostly marketing gimmicks—they don't provide any significant amount of additional protection.

SPF 30 sunscreen blocks 97 percent of UVB rays, which is enough for most situations.

Sunscreens Protect Against the Sun's 2 Types of Radiation: UVA and UVB

Not always. In June 2012, the FDA announced new labeling requirements so that only products that pass a broad spectrum test, providing protection against both UVA and UVB rays, are allowed to have the "Broad Spectrum" label. Prior to the new FDA standards, manufacturers commonly made inaccurate claims about UVA protection, since the SPF rating only applies to UVB protection. 

Applying Sunscreen Once Per Day Is Enough

No. Sunscreen should be applied every two hours—even more if you're swimming or sweating a lot. Even so-called "water-resistant" sunscreens may lose their effectiveness after 40 minutes in the water.

Stored Bottles of Sunscreen Last Forever

No. Sunscreen loses some of its effectiveness after one year and is mostly ineffective after three years.

Have leftover tubes of sunscreen from last summer? Unless they have an expiration date, toss them.

A Little Dab of Sunscreen Works Just as Well as a Lot

No. The recommended amount to apply is more than you might think: 1 ounce, or a full palmful (or shot glass). Make sure to apply it to dry skin 15 to 30 minutes before going outdoors to allow it time to be absorbed into the skin.

If It's Cloudy, You Don't Need to Worry About Sunscreen

No. Up to 80 percent of the sun's ultraviolet rays can pass through the clouds. In addition, sand reflects 25 percent of the sun's rays and snow reflects 80 percent.

Sunscreen Blocks the Body's Ability to Make Vitamin D

One reason many people say they don’t use sunscreen is the fear of blocking vitamin D development in the body, a process that requires sun exposure. However, concerned individuals can boost their vitamin D production by taking daily supplements or eating a diet rich in fish, fortified milk, and eggs. In fact, most people get enough sun exposure just doing everyday outdoor activities, such as walking to the bus stop, even when sunscreen is applied.

Using Sunscreen Is Enough to Prevent Skin Cancer

No. Studies show that applying sunscreen every day can indeed reduce the formation of actinic keratoses (also called solar keratoses), which can develop into the more serious squamous cell skin cancer. However, other ways to protect yourself from the sun are even better—and at upwards of $10 per tube, using high-quality sunscreen in the proper manner can be very expensive.

So what's the alternative? Simple: Just stay out of the sun in the middle of the day. If you're at the beach, use an umbrella. Minimally, wear a wide-brimmed hat and a shirt. And completely avoid tanning salons.

Heeding these simple safety tips just may protect you from the sun's harmful rays.


How Do I Protect Myself from UV Rays? American Cancer Society.

Who's Using Sunscreen? Consumer Reports National Research Center.

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