ATLANTA -- Summer is officially here. Are you protecting your skin from the sun? Do you know what SPF (sun protection factor) to use? We spoke with Piedmont dermatologist Jodi Ganz, M.D., to find out what those SPF numbers really mean.
“The SPF number means it would take you that much longer to burn than you normally would without sunscreen,” says Dr. Ganz. “If it takes you 10 minutes to burn, then using an SPF5 means it would take you five times longer, or 50 minutes, to burn. An SPF10 means you could stay in the sun 10 times longer, or 100 minutes.”
But Dr. Ganz cautions that most sunscreens “break down” on average in two hours, meaning they lose their ability to protect you. So, you must reapply sunscreen every two hours.