Going Skin Deep

What they do: These vitamin A derivatives block the degradation of the skin's structural proteins and interrupt the chemical pathways of UV skin damage.

Where to find them: In three prescription creams -- Renova, Retin-A and Avage -- and in over-the-counter retinol creams such as Estee Lauder Diminish Anti-Wrinkle Retinol Treatment.

Do they work?: Retinoids "increase cell turnover, reverse signs of photoaging and allow you to smooth out fine lines and lighten brown spots," Kazin said. Retin-A was developed in the 1970s to treat severe acne. Read said she prescribes retinoids regularly for mild to severe signs of photoaging, though not for women considering pregnancy because retinol can cause severe birth defects. Extensive clinical data and FDA approval support this approach.

Antioxidants

The approach: Replenishing the body's stores of skin-protective antioxidants, which diminish with age.

Examples: Vitamins A, C and E, coenzyme Q10, polyphenols.

What they do: Kazin said antioxidants "slow down the aging process," which occurs when ultraviolet rays from the sun generate free radicals -- reactive forms of oxygen that damage DNA and proteins in skin cells -- trigger inflammation and wreak havoc on the support structures underlying the skin. Antioxidants "basically mop up the free radicals and let the skin heal itself," Read said.