SPF: A measure of how long it would take skin to burnEmma Kapotes/Rd.com, iStock/Grassetto
The sun protection factor of a sunscreen indicates how long it would take for your skin to burn when using the product compared to how long your bare skin would take. For instance, when you wear a sunscreen with SPF 15, your skin will take 15 times longer to turn red than it would without any sunscreen. A higher SPF might not give as much additional protection as you’d think though. SPF 30 blocks 97 percent of UVB rays, while SPF 50 blocks 98 percent. Only SPF 15 and higher has been shown to reduce cancer risk and prevent premature skin aging, but the FDA says there’s no evidence that anything higher than SPF 50 will protect you any better. Believing these sunscreen myths could sabotage your skin.
Broad spectrum: Blocks UVA and UVBEmma Kapotes/Rd.com, iStock/Grassetto
The FDA lets products use the term “broad spectrum” if they protect against both ultraviolet B and ultraviolet A radiation. Most sunburn is caused by UVB, but both types can cause sunburn, skin cancer, and skin aging. You might not realize you’re making these sunscreen mistakes.