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Glossary / Skincare

SPF (Sun Protection Factor)

SPF stands for Sun Protection Factor — a number on sunscreen that tells you how much UVB protection it offers. SPF 30 blocks about 97%% of UV rays, and SPF 50 blocks about 98%%. No sunscreen blocks 100%%, and all sunscreens need to be reapplied every 2 hours. Look for "broad spectrum" on the label to ensure protection against both UVA and UVB rays.