Does Applying Sunscreen Work?

Does sunscreen work? It absolutely does reduce your risk of sunburn. That's crystal clear, because every commercial sunscreen is smeared on a person and the SPF is calculated by actually observing how much more ultraviolet light it takes to give that person a sunburn while they're wearing sunscreen.

Is applying sunscreen really necessary?

Always wear sunscreen, no matter your skin color or tone. ... Sunscreen is an important preventive health care habit that should be maintained all year, including the winter months. Snow can reflect up to 80 percent of ultraviolet (UV) rays, increasing your risk of exposure to sun damage.

How long does sunscreen last after applying?

A sunscreen's sun protection factor (SPF) is only fully effective for two hours after you put it on. Experts recommend carrying a bottle of SPF 30 to SPF 50 sunscreen around with you, even on cloudy or rainy summer days, so you can throw some on if the sun comes out.