The Basics
Hopefully, you're heard these before, but let's reapply.
Dependind on your body size, experts recommend using enough lotion to fill a shot glass, or 30g, when you're at the beach. Even if people are smart enough to apply sunscreen, the may not us enough, said Dr.Jerry Brewer, a dermatological surgeon at the Mayo Clinic in Minnesota.
Even if the bottle says the lotion is waterproof, beachgoers should reapply after swimming.
If you're not swimming, you should reapply every two hours, regardless of the SPF count.
You should put sunscreen on 15 minutes before exposure. Look for products that are labelled "broad-specttrum protection", with an SPF of 15 to 50.