What's the Difference Between Sunscreen and Sunblock?

As a former food writer, I have a complicated relationship with seasonality. When you’re banned from writing about tomatoes and eggplant and corn outside the hours of late July to early September, you know what you want to do? You wanna write about tomatoes in December. 

So with What’s the Difference, we’re deciding that seasonality is a construct. (Unless it serves the purpose of a cute newsletter introduction—in that case, we love the seasons.) And unlike tomatoes in December, which are objectively gross, sunscreen and sunblock should be worn year-round! But before we get to skincare tips, let’s dig into the difference.

Sunscreen is a lotion that absorbs the sun’s ultraviolet (UV) rays; it contains chemicals that soak them up before they reach the skin. It’s therefore referred to as a chemical sunscreen. Sunscreens can have a wide range of active ingredients, but the good ones contain benzophenones, which protect against UVA rays (the ones that cause premature aging and wrinkling), and cinnamates and/or salicylates, which protect against UVB rays (the ones that cause sunburns). 

Sunblock, on the other hand, reflects the sun’s rays from the skin instead of absorbing them. It’s therefore thought of as a physical sunscreen. Sunblock is usually thicker and more opaque than sunscreen, and it can sometimes leave behind white residue. And although it’s heavier, sunblock’s active ingredients—titanium dioxide or zinc oxide—are gentler, making it a safer choice for people who have sensitive skin.

Dermatologists say that unless you have a personal preference, both sunscreen and sunblock are fine to use—one’s not better than the other. However, whatever you choose should have an SPF of at least 30 and protect against both UVA and UVB rays; if you see the term “broad spectrum” on the label, you’re good to go. And make sure to avoid suntan lotion, which is a different product altogether; it usually has an SPF of 15 or lower, and is made with oils that don’t protect your skin at all. You might want that sun-kissed look, but safety comes first—no matter what season it is.

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