Our Verdict
When comparing physical sunscreens to chemical sunscreens, we picked the physical sunscreens.
Why?
It’s easy to vote against chemical sunscreens, because it has “chemical” in the name, which tends to be offputting PR-wise no matter how healthy something is.
But in this case, there’s actual science here too!
Physical sunscreens physically block the UV rays.
- On the simplest of levels, mud is a physical sunscreen, as you can see widely used by elephants, hippos, pigs, and other animals.
- On a more sophisticated level, modern physical sunscreens often use tiny zinc particles (or similar) to block the UV rays in a way that isn’t so obvious to the naked eye—so we can still see our skin, and it looks just like we applied an oil or other moisturizer.
Chemical sunscreens interact with the UV rays in a way that absorbs them.
- Specifically, they usually convert it into relatively harmless thermal energy (heat)
- However, this can cause problems if there’s too much heat!
- Additionally, chemical sunscreens can get “used up” in a way that physical sunscreens can’t* becoming effectively deactivated once the chemical reaction has run its course and there is no more reagent left unreacted.
- Worse, some of the reagents, when broken down by the UV rays, can potentially cause harm when absorbed by the skin.
*That said, physical sunscreens will still need “topping up” because we are a living organism and our body can’t resist redistributing and using stuff—plus, depending on the climate and our activities, we can lose some externally too.
Further reading
We wrote about sunscreens (of various kinds) here:
And you can also read specifically about today’s topic in more detail, here:
What’s The Difference Between Physical And Chemical Sunscreens?
Take care!
