Sunscreen

By Andréa Ford Monday, July 18, 2011

    • The FDA's long-awaited sunscreen-labeling reforms, which take effect in 2012, address concerns that consumers don't fully understand how--or how well--sunscreen combats damage done by the sun

    HOW SKIN GETS BURNED

    1 When skin is exposed to the sun, UV rays stimulate cells in the bottom layer of the epidermis

    Epidermis

    2 Pigment cells go to work, producing melanin, which darkens skin and protects DNA

    Melanin

    3 When the melanin defense is overwhelmed, cell damage occurs, and the body boosts blood flow to aid healing, causing inflammation

    Dermis

    Blood flow

    UVA rays, responsible for most UV radiation reaching the earth, penetrate deeply and may contribute to cancer and aging

    UVB rays, higher in energy and more variable with time of day and season, cause sunburn, increasing cancer risk

    Sunscreen

    UV rays

    SUNSCREEN FIGHTS BACK

    On the surface

    Sunscreen contains compounds like zinc oxide that act as a UV barrier and absorb or reflect rays before they ever touch the body

    Sunscreen molecules

    In the skin

    Some UV energy makes it through. Sunscreen molecules convert damaging UV to less harmful energy, which then radiates back out