How Does Sunscreen Work? Sunscreen contains one or more active ingredients (UV filters) that protect the skin from exposure to UV rays. UV filters can be classified into two groups: mineral and organic. Mineral filters—sometimes called inorganic or physical—work by deflecting and reflecting UV light, preventing the UV light from hitting your skin. They are effective at protecting against both UVA
One blistering sunburn in childhood or adolescence more than doubles your chances of developing melanoma later in life.
and UVB radiation. The two mineral filters (active ingredients) used in U.S. sunscreen are zinc oxide and titanium dioxide. Organic filters—sometimes called chemical—work by absorbing UV light energy. They can protect against UVA, UVB, or both. The six organic filters (active ingredients) most commonly used in U.S. sunscreens are avobenzone, homosalate, octinoxate, octisalate, octocrylene, and oxybenzone. Broad spectrum sunscreen has filters that protect against both UVA and UVB rays. Most U.S. sunscreens combine two or three of the above eight filters to get the best performance. Importantly, only three of these ingredients—oxybenzone, avobenzone, and zinc oxide—protect significantly in the UVA range.
What active ingredients (UV filters) are available in the U.S. as of today? There is a simple and a complicated answer to this question—and the bulk of this article will explain the complicated answer. But, as of this writing, the simple answer is: Sixteen active ingredients are available to be marketed in the U.S. and are currently designated as generally recognized as safe and effective, or GRASE. These 16 ingredients are the same ingredients that have been available to U.S. consumers for several decades. They are: The two mineral filters noted above: zinc oxide and titanium dioxide The six organic filters most commonly used in U.S. sunscreen, noted above: avobenzone, homosalate, octinoxate, octisalate, octocrylene, and oxybenzone Six other organic filters less commonly used in U.S. sunscreen: cinoxate, dioxybenzone, ensulizole, meradimate, padimate O, and sulisobenzone Two organic filters no longer used in U.S. sunscreen: aminobenzoic acid (PABA) and trolamine salicylate How we got to this moment—with these 16 ingredients designated GRASE—is a convoluted story.
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