Going Skin Deep

Where to find them: SkinCeuticals products (containing vitamins C and E), Boots No. 7 Restore & Renew Beauty Serum (with pro-retinol, a form of vitamin A), Revaleskin products (polyphenols) and the ABRA therapeutic line (polyphenols).

Do they work?:"It is an improvement, a clear improvement," Read said of antioxidants as a whole. Studies show that vitamins C and E are effective in combination, though vitamin C may do little on its own. In studies, polyphenols derived from green tea, fruits and vegetables reduce UV-induced DNA damage and inflammation.

Hydroxy Acids

The approach: Sloughing off dead cells while increasing skin's thickness.

The ingredients: Alpha hydroxy acids (lactic acid, malic acid, citric acid, glycolic acid) and polyhydroxy acids (gluconolacton, lactobionic acid).

What they do: The acids work to increase the skin's thickness and the density of the collagen fibers that are responsible for the skin's strength and elasticity. They also have apparent antioxidant properties.

Where to find them: Neutrogena Healthy Skin Eye Cream (alpha hydroxy acids), Exuviance products (polyhydroxy acids).

Do they work?: Studies show that these fruit acids decrease wrinkling, roughness and discoloration. "They really do produce significant reversal," Read said, though alpha hydroxy acids can cause mild to severe skin irritation.

Ishani Ganguli is a second-year student at Harvard Medical School. Comments:health@washpost.com.