Ask the Experts; January 2006; Scientific American Magazine; by Suzan Obagi, Jeffrey Hovis; 1 Page(s)

Wrinkles arise from physical shifts that occur naturally as we grow older--and they are exacerbated by outside influences, such as exposure to sun or tobacco smoke.

As we age, we gradually lose our collagen, a protein fiber that makes our skin firm; as a result, skin becomes thinner and more fragile. We also begin to lose the elastin that gives skin its elasticity and its glycosaminoglycans, or GAGs, which enable it to hold moisture. The result is drier skin with wrinkles that don't go away. Such changes, however, occur slowly and account for only a small amount of our furrows.