What is SPF? SPF = sunburn protection factor

Image courtesy of Wikipedia user Axelv.

One day after Tropical Storm/Hurricane Irene passed through town, the sun is back! Perfect time to learn about sunscreen.

A common question is: what is SPF? SPF stands for sunburn protection factor. (The FDA changed it from sun protection factor to sunburn protection factor as sunscreen does not completely protect you from the harmful UV of the sun.) The number is a measure of how many times more it takes for you to burn with the sunscreen on compared to not wearing the sunscreen. So for instance, if it takes a certain amount of UV rays for you to become red without sunscreen, it would take 15 times that amount of UV for you to become red when you wear SPF 15 sunscreen. The SPF label assumes that you correctly apply the sunscreen. You should use about 1 ounce to cover the surface of your body. Furthermore, you need to reapply the sunscreen as you sweat, or get wet. Additionally, the SPF value on bottles refers to harmful UVB (ultraviolet-B) rays, but not harmful UVA rays. When choosing a sunscreen, look for one that covers UVA and UVB (“broad spectrum” sunscreens).

Leave a Comment

Your email address will not be published. Required fields are marked *