These creams have some chemical that blocks the UV with some capacity, say a factor of 50. Why can’t I apply two layers of this cream to now get a 100 factor equivalent protection?
I asked the chemist at the store and they said it’s not how it works and that the highest protection factor they have is 75 (which was super expensive).
What gives?
Edit: Thank you for those super informative answers.
Us has 16 of uv filters aproved, whereas EU has 30+. Last UV filter aproved by FDA was in 1999. So us had old sun screens
I didn’t know that. Thanks for the info.