Like HowStuffWorks on Facebook!

What's the one thing you can do to improve your skin?

For Health
Sun protection can save a lot more than your looks.
Sun protection can save a lot more than your looks.
Photo courtesy of U.S. FDA

The power of the sun should not to be underestimated. More people in the United States end up with skin cancer than any other type [source: NIH]. One million cases are diagnosed annually, and some of them are melanoma, the most deadly of the skin cancers [source: AAD]. Using sunscreen -- and using it properly -- goes a long way toward preventing these health conditions.

Sunscreen actually blocks the sun's rays from penetrating the skin, either by reflecting or scattering it, so it can't cause cell damage. Both UVA and UVB can contribute to the development of skin cancer, so a broad-spectrum sunscreen is the best type. But even the best sunscreen only works if people use it as directed. Most people don't.

First, active ingredients don't immediately take full effect. Apply sunscreen at least 15 minutes before you'll be in the sun. Also, sunscreen wears off and loses potency, so you need to reapply it every two hours and after swimming or sweating. Apply it liberally -- it should take an ounce to cover all of your exposed areas, which includes hands, face (including lips! -- look for an SPF lip balm), neck, ears, forearms and any other part not covered by clothing. Also, don't mix it with moisturizer before rubbing it in, since you're basically diluting the active ingredients.

And finally, contrary to logic, you don't have to be outside in the sun to be exposed to sunlight. Some of the sun's rays -- the UVA ones -- can make it through glass windows. So being indoors is no reason to skip the daily application.

The best approach is to simply make sunscreen a part of your morning routine: Don't leave the bathroom without it. Just think of applying sunscreen as being as crucial as brushing your teeth, because it is. Your healthy, young-looking skin will thank you for it.

For more information on sunscreen and related topics, look over the links on the next page.