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.
I looked up sunscreen recommendations on Consumer Reports and virtually every sunscreen didn’t perform as well as advertised in CR’s lab tests. CR’s top rated sunscreens all happen to be marketed for kids/babies oddly enough.
You get sunburned: “oh, silly me, I must have forgot to reapply”
Your baby gets sunburned and spends the next 72 hours crying: “I will murder the CEO of Johnson & Johnson”