Sunscreen Science: What SPF and PA Ratings Actually Mean
Walk down any sunscreen aisle and the labels read like a code. SPF 30. SPF 50+. PA+++. PA++++. Broad spectrum. Water resistant. Most people pick the biggest number and hope for the best. So what do SPF and PA ratings mean? SPF tells you how well a sunscreen protects against UVB rays, which cause sunburn. […]