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Why UVA and UVB Matter

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 your skin type

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 [16] 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 [17] 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.

Links to Suncreen Articles...