what happens to sun screen when you apply it? Does it all get absorbed into your skin or does it sweat off? How does it protect your skin from the UV rays?

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what happens to sun screen when you apply it? Does it all get absorbed into your skin or does it sweat off? How does it protect your skin from the UV rays?

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Sunscreen is paint. It’s skin safe, non-alergenic, paint. But instead of having pigment you can see, it has pigment which is clevr in the visible light range, but black in the UV light range that burns you.

It comes off, mostly through wear, because if it was tough, that wouldn’t be skin safe. It protects you, like house paint protects your house, by blocking the UV light.

Some of the elements in sunscreen physically block and reflect the ultraviolet light. Other elements actually absorb the ultraviolet light, breakdown chemically and release heat.

It protects your skin by absorbing the UV rays, most of the energy of which is then dissipated as heat, so in a way it acts as a shield.

Although it is commonly repeated that some sunscreen components reflect UV radiation and others absorb it, in reality it is mostly by absorption that it effects its protection, which is why if you look at UV images of someone wearing sunscreen, the area where it was applied is rendered as black (absorbing light, in this case UV light).

We used to think sunscreen would just sit on your skin without being absorbed and be worn/washed away, but studies starting on 2020 show that a part of the most common ingredients do get absorbed through the skin and into the bloodstream, ending up in urine and breast milk, which is why now we are taking a closer look at possible adverse effects of these ingredients (still to be derermined).