Lesson 1: There’s two types of sun rays
A lot of confusion about sunscreen tends to stem from this one fact. There are two different types of UV rays from the sun – UVA and UVB – and they work in different ways. “UVB has a shorter wavelength but has higher energy,” explains Dr Stefanie Williams, a cosmetic dermatologist and founder of Eudelo clinic in London. “It has more aggressive effects on the skin, but it is filtered out quite easily.”