If you think all sunscreens touting high SPFs—like those with 50s on their labels, for example—are equally effective, here’s a surprise: Consumer Reports has found that those SPF numbers aren’t always a reliable measure of how much protection you’ll get. If you put too much faith in them, you could be putting your skin at risk.
SPF, which stands for sun protection factor, is a measure of how well a sunscreen guards against ultraviolet B (UVB) rays, the chief cause of sunburn and a contributor to skin cancer. Assuming you use it correctly, if you’d burn after 10 minutes in the sun, an SPF 30 protects for about 5 hours. But the intensity of UVB rays varies throughout the day and by location, and all sunscreens must be reapplied every 2 hours you’re in the sun.
And everyone—including babies 6 months and older—needs to use sunscreen. People of color have some natural protection against UV rays. How much depends on the amount of the pigment melanin in their skin. But they are still susceptible to sunburn and skin cancer, so experts stress that sunscreen is a must for every skin tone.
For the fifth year in a row, CR’s testing has shown that some sunscreens failed to provide the level of protection promised on the package. Of the more than 60 lotions, sprays, sticks, and lip balms in our ratings this year, 23 tested at less than half their labeled SPF number.
And CR isn’t the only independent consumer organization that has found this discrepancy. Other members of International Consumer Research and Testing (a global group of consumer organizations) in Australia, New Zealand, and the U.K. have also found differences between the labeled SPF and the tested SPF in sunscreens on the market in those countries.
The ABCs of SPF
Sunscreens are classified as over-the-counter drugs. The Food and Drug Administration requires manufacturers to have their products tested to determine the SPF. But the agency doesn’t routinely test sunscreens itself. Manufacturers don’t have to report their results, although they do have to submit them to the FDA if the agency requests them.
At a public meeting last June, an FDA official said the agency had the resources for only about 30 employees to cover more than 100,000 over-the-counter drugs. That limits what it can do to oversee sunscreens.
“Most of the time, a sunscreen’s effectiveness has been verified only by the manufacturer and any testing lab it might decide to use—and not by the government,” says William Wallace, an analyst for Consumers Union, the policy and mobilization arm of Consumer Reports.
Manufacturers test sunscreens for SPF before their products hit the market, but unless they are reformulated, that may be the only testing they do. That’s one reason CR tests sunscreens.
We use the FDA’s sunscreen testing protocol as a model, but as with all products, we do our own scientific, laboratory-based testing to identify differences in performance and give consumers a comparative evaluation. Every sunscreen is tested at a lab in the same way. “We buy sunscreens off the shelf, the way consumers would,” says Susan Booth, the project leader for our sunscreen testing. “We use three samples, preferably with different lot numbers, of each product.”
To check for UVB (SPF) protection, a standard amount of each sunscreen is applied to small areas of our panelists’ backs. Then they soak in a tub of water. Afterward, each area is exposed to six intensities of UVB light from a sun simulator for a set time. About a day later, a trained technician examines the areas for redness. The resulting UVB protection ratings reflect each product’s actual effectiveness after water immersion and are based on an average of our results for each sunscreen.
With some sunscreens, even though our tested SPF varied from the labeled SPF, the product still provides acceptable UVB protection. For example, Coppertone Ultra Guard Lotion SPF 70+ received a Very Good score for variation from SPF in our tests. That means it tested within 70 to 84 percent of the labeled SPF, coming in at an SPF of more than 49 in this case. That got the product an Excellent rating for UVB protection and a recommended designation.
But with other products, missing the mark could mean that you’re not adequately shielding your skin. An SPF 50, say, that tests at less than half its labeled SPF delivers an SPF 24 at the most, and sometimes far less. (The American Academy of Dermatology recommends using a product with an SPF of 30 or more.)
For example, in our tests, Coppertone Sport High Performance Spray SPF 30 earned a Poor rating for variation from its SPF because the tested SPF was less than half the value listed on the label. We also rated it Fair for UVB protection because the tested SPF was between 10 and 19.
But other Coppertone sunscreens received high scores for variation from SPF and for UVB protection, which illustrates why you can’t always choose by brand.
Beth Jonas, Ph.D., chief scientist at the Personal Care Products Council, a trade association that represents the sunscreen industry, said that it disagreed with our findings. She noted that our test methods aren’t the same as required by the product manufacturers to assign the SPF designation and can’t be directly compared with a label claim.
Why UVA and UVB Matter
A sunscreen’s SPF is only one gauge of the protection it provides. Equally important is broad-spectrum coverage, or how a product shields your skin from UVA rays as well as UVB. With their longer wavelength, UVA rays reach the middle layer of the skin (the dermis), damaging cells and triggering changes that can lead to skin cancer, broken blood vessels, sagging, and wrinkling. Most of the sun’s radiation is in the form of UVA. Unlike UVB rays, which are strongest from 10 a.m. to 4 p.m., UVA rays are present throughout the daylight hours, even on cloudy days.
There’s no labeling system in the U.S. that indicates a sunscreen’s level of UVA protection. And the test the FDA requires manufacturers to perform if they want to label their sunscreen broad-spectrum (called the critical wavelength test) is pass/fail. All of the sunscreens in our tests would have received a passing grade on that test, but some sunscreens do a better job than others.
The test that CR does is similar to one used in Europe and allows us to measure the degree of UVA protection. To test for UVA protection, we smear sunscreen on plastic plates, pass UV light through, and measure the amount of UVA and UVB rays that are absorbed. That information is then used to calculate our UVA score. Two-thirds of the products in our ratings earned at least a Very Good UVA score.
Find the Right Sunscreen for You
When you wear sunscreen, you should feel confident that you’re well-defended against UVA and UVB rays and that you’re actually getting the level of protection promised on the label. That’s where our ratings come in. This year, we have 15 recommended sunscreens that received Excellent overall ratings and 20 others that didn’t make our recommended list but were still rated Very Good overall.
If you can’t find one of these products, we suggest using a sunscreen labeled with an SPF of at least 40 that contains chemical active ingredients such as avobenzone rather than “natural” or mineral active ingredients such as zinc oxide. In our past five years of testing, we’ve found that this offers the best chance of getting a sunscreen that delivers at least an SPF 30.
Editor's Note: This article also appeared in the July 2017 issue of Consumer Reports magazine.
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