The sun produces two kinds of rays, visible and invisible. Both types cause sunburn, suntan and sun damage. A suntan is the skin's response to injury from sunlight. When UV rays enter the skin, the skin protects itself by producing melanin.
Melanin is a substance produced by the skin that makes it darken.
What the sun does to your skin. Sunscreens are topical chemicals that work by absorbing, rejecting, or scattering the sun's rays. They are labeled with SPF numbers. For example, if you normally burn in 10 minutes, a sunscreen with a SPF of 15 will let you stay in the sun for about 150 minutes without burning. For more information, contact the First Physicians Network Health Forum by clicking on the navigation button at the bottom of this page.