SPF 30 vs SPF 50 are often compared with SPF 100, but these numbers do not simply represent percentages of UVB protection.

SPF 30 vs SPF 50 are commonly compared when choosing sunscreen, but these numbers do not simply represent percentages of UVB protection. This explanation is convenient, but it can make the differences between sunscreens appear smaller than they really are. SPF works as a biological protection factor based on the ultraviolet dose needed to produce […]