5 Ways You Might Be Using Sunscreen Wrong

It happened in Huntington Beach, Calif. College freshman Matt Brady, fresh off the plane from Colorado, hit the beach for some fun in the sun. Sunscreen: check. But by the end of the day, disaster struck.

“I transformed into a lobster on my front, back, top, bottom, ears, toes, everything,” he says. “My roommate had to apply aloe vera onto me for about six days straight, and I couldn’t sleep.”

Where did he go wrong? “At about 10 a.m., I put on SPF 30. And then never reapplied over the next six hours,” he admits. Big mistake.

Brady’s not alone—almost everyone has a bad sunburn story, and most of them can be traced back to a lack of sun protection. In 2012, 50 percent of young adults experienced a sunburn. But even worse: over two million people are diagnosed with skin cancer each year, according to the Skin Cancer Foundation. Watch out for these five blunders you might be making when it comes to sunscreen.

1. Using sunscreen with potentially harmful chemicals

If you’ve heard rumblings about certain sunscreens being “bad” for you, it all comes down to a few questionable ingredients. Two in particular rate high on the Environmental Working Group’s toxicity scale: oxybenzone and octinoxate. According to research cited by EWG, both may produce chemically reactive molecules that can interfere with cell signaling, potentially leading to mutations that disrupt cells’ functions (like creating energy or multiplying for growth and tissue repair). Octinoxate could also disrupt the endocrine system and change the body at the cellular level—yikes.

If you’re concerned about these chemicals, Dr. Rosalyn George, an MD and dermatologist at the Wilmington Dermatology Center in N.C., recommends using a sunscreen that has solely zinc oxide or titanium oxide. Look for the word “sunblock” on the label—often, that means it’s zinc oxide– or titanium oxide–based. (Some such products will still labeled as “sunscreen,” though.)

2. Skipping sunscreen on cloudy days

When we don’t feel the direct heat of the sun, we may unwittingly subject our skin to sun damage. Just because it’s overcast doesn’t mean you’re safe from UV rays, which can still penetrate a thick veil of clouds. Protect your skin no matter what the forecast is—even in winter, but especially in the summer.

3. Forgetting to reapply

Slathering on sunscreen in the morning and calling it a day is just asking for trouble. “Reapply every two hours or after exposure to water or excessive sweating,” Dr. George says. Even “water-resistant” sunscreens warrant a touch-up after 40 to 80 minutes of swimming or sweating, according to George.

4. Reaching for a super high SPF

SPF stands for “sun protection factor,” and it’s based on the amount of protection a sunscreen or sunblock offers against UV rays. But the SPF number on the bottle can be deceiving. The differences between SPF 30, 50, and 100 are marginal at best—SPF 30 already blocks out about 96 percent of UV rays, while SPF 50 only blocks 2 percent more. In other words, 30 is good enough.

George explains, “Basically, an SPF of 30 means that it would take you 30 times longer to burn than if you didn’t wear any protection.” So, say you burn within 10 minutes without sunscreen. With SPF 30, you could extend that to 300 minutes, or five hours. But by that time, you should have already reapplied anyway, so using a higher SPF would be superfluous.

5. Using last summer’s bottle

All those half-empty tubes at the bottom of that beach tote you haven’t used in a year (or two, or three)—it’s time to toss ’em. The active ingredients in sunscreen can deteriorate over time, so pay attention to the expiration date. Dr. George says most sunscreens should still be effective for three years, but recommends replacing them yearly to be safe.

So, for maximum protection, Dr. George suggests looking for a sunscreen labeled “broad spectrum” and “water-resistant up to 80 minutes,” with SPF of 30. But even if you are vigilant about all of the above, you’re still not completely invincible to the sun’s aging effects or skin cancer risk. “Remember to seek shade when available and use protective clothing, hats, and sunglasses, too!” says Dr. George.

Photo credit: Alicia Cho