Are You Getting Enough Protection from Your Sunscreen?

A recent study by Northwestern Medicine revealed 40 percent of the top sunscreen products on Amazon did not meet the American Academy of Dermatology’s recommended guidelines. (Joe Shlabotnik / Flickr)A recent study by Northwestern Medicine revealed 40 percent of the top sunscreen products on Amazon did not meet the American Academy of Dermatology’s recommended guidelines. (Joe Shlabotnik / Flickr)

Summertime in the city means outdoor activities and lots of time spent soaking up the sun. But before you slather on your favorite sunscreen, take a closer look at the bottle—it might not be providing as much protection as you need.

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Of the top-selling sunscreens on Amazon.com, 40 percent did not meet the American Academy of Dermatology’s standards, according to a recent study by Northwestern Medicine.

“As dermatologists, probably one of the most frequent questions we’re asked by our patients is, 'What kind of sunscreen should we use?' I get asked that pretty much almost every single day,” said Dr. Steve Xu, a resident physician in dermatology at Northwestern University and lead author of the study.

“Although we have specific performance guidelines for sunscreens, we didn’t really know exactly what consumers liked,” he added. “That’s a very important issue because if I’m going to prescribe you a recommended sunscreen and it’s chalky or it smells bad or it’s too expensive, you may not use it.”

To learn consumers’ sunscreen preferences, researchers turned to Amazon.

“I was cruising on Amazon and I came up with this idea: This is a huge source of information. There’s tens of thousands of reviews, there’s more than 6,000 sunscreen products,” Xu said. “It’s essentially a library with real-time feedback.”

With more than 6,500 sunscreen products listed on Amazon, researchers chose “to look at the top 1 percent—the 65 that got the highest reviews and were the most frequently reviewed,” Xu said. Products that had high ratings but few reviews were avoided, he explained.

These products were then assessed according to the AAD guidelines. Dr. Xu declined to address the performance of specific brands analyzed. The study’s goal, he said, was to offer best practices to both consumers and dermatologists for selecting and recommending products.

“As dermatologists, we really try to depend on objective metrics of product performance in our recommendations. The Academy of Dermatology’s guidelines really respect that,” Xu said.

Tips for selecting and applying sunscreens

Expert advice: Pick a sunscreen that’s at least SPF 30, water resistant and broad spectrum. (Robert S. Donovan / Flickr)Expert advice: Pick a sunscreen that’s at least SPF 30, water resistant and broad spectrum. (Robert S. Donovan / Flickr)

When it comes to sunscreens, choose one that has a sun protection factor—aka SPF—of at least 30 and make sure the label says water-resistant (or sweat-resistant) and broad spectrum, meaning the product blocks both UVA and UVB rays.

“The number one risk factor [for skin cancer] is exposure to UVA and UVB sunlight,” said Dr. Sigrun Hallmeyer, an oncologist who specializes in melanoma and breast cancer. Hallmeyer, who has been practicing for more than a decade with Oncology Specialists, a medical group with locations in suburban Park Ridge and Niles, said she has seen an increase in the incidence of skin cancer and a change in the demographics of patients.

“This used to be a disease of the older and elderly population. We have a lot of patients now who come to us as early as their late teens or early 20s and 30s,” she said. “If you think about the incidence in general in the 1930s, which is really just one generation before us, the incidence of melanoma was 1 in 1,500 people and now it’s about 1 in 50. So there’s an exponential growth in the incidence of that.”

Although malignant melanoma can develop at any time, Hallmeyer says “the biggest risk for the development of malignant melanoma over a lifetime is sun exposure in the teenage years.”

From around age 10 to 22, “our body mass is expanding very rapidly so there’s a ton of DNA replication during that time,” Hallmeyer said. As the DNA replicates, “it opens up the possibility of errors being made. Our body is very well able to correct those errors, but when a particular insult to a cell has happened [such as] in the case of malignant melanoma, say a UVA radiation insult, you may ultimately not be able to repair the mistake that happened in your DNA replication.”

While 40 percent of the sunscreens analyzed didn’t meet the AAD standards, Xu said the majority of the time it was because they were not water-resistant.

Half of the sunscreens analyzed by Northwestern that didn’t meet the Academy of Dermatology standards were not water-resistant. Half of the sunscreens analyzed by Northwestern that didn’t meet the Academy of Dermatology standards were not water-resistant.

Sunscreens that are water- or sweat-resistant often provide label information about the duration of the resistance. But Hallmeyer says people should be applying their sunscreens more frequently than that.

“That really cannot be trusted because ultimately the way these things are tested is under the surface of the water to see how long [the sunscreen] takes to break down. But we’re not just going into the water and being still,” she said.

“We’re doing activities, we’re swimming, we’re touching each other and ultimately, any time that happens you have an abrasion on your skin surface that will remove your sunscreen, so we recommend anybody who’s in a water sports-type of activity to reapply. Leave the water and reapply [sunscreen on] the exposed areas.”

Picking the right sunscreen is just the first step, say Xu and Hallmeyer. The average person doesn’t use enough sunscreen and doesn’t wait enough time after application before going out into the sun.

Adults should use at least one ounce of sunscreen on exposed skin (that's about the amount that would fill a shot glass). After applying sunscreen, remain indoors or in the shade for at least 15-20 minutes to allow the sunscreen to be absorbed. Sunscreen should be reapplied at least every two hours—more often if you’re going in and out of the water or sweating.

“This study has really changed my own counseling of patients: I can tell them, ‘Look for SPF 30, look for broad spectrum, look for water resistance,’ especially in the context of water sports or if you’re going to be swimming a lot,” Xu said. “Remember that everything else is really just marketing claims, not regulated. … Ultimately, I think you can get a product that’s very effective at protecting your skin that is uniformly liked on average by consumers that’s also affordable. All of those factors need not be mutually exclusive.”

Follow Kristen Thometz on Twitter: @kristenthometz


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