Why do sunscreen formulations damage at high temperatures but function on human skin?

Question

Seems like most sunscreens include labels saying to store below 30 degrees (celsius) or risk reduced efficacy, but how do they function on the skin (which would be, on average, higher than 30 degrees?)?

In: 3

Answer 1

>Seems like most sunscreens include labels saying to store below 30 degrees (celsius) or risk reduced efficacy, but how do they function on the skin (which would be, on average, higher than 30 degrees?)?

Sunscreen is applied to your skin as a sacrificial layer. Its components disintegrate under UV radiation (so your skin doesn’t), that’s its *purpose*.

Naturally you don’t want the product to break down before you apply it.