A sunscreen labeled “SPF 15” should let you spend about 15 times as long in the sun before you burn. Pretty awesome, right? Unfortunately, most of us don’t get that level of protection because we don’t apply enough. What you’re likely getting: a mere SPF 2.
We should be using about an ounce of sunscreen, or almost a shot glass full, to get the recommended 2 milligrams per square centimeter of skin. That’s what the label’s SPF is based on. But most of us use a lot less: 20% to 50% of the recommended amount. That means we’re not getting the protection we think. Here’s a handy chart from the Environmental Working Group’s sunscreen tests:
Actual Effective SPF Rating
So if you’re thinking that the SPF 100 protects you much better than the SPF 15, it doesn’t—unless you apply the recommended amount. Read more at the link below about the science behind choosing a good sunscreen.
The Great Sunscreen Cover-Up | Science Based Medicine
Article by Beth Skwarecki