Let's face it: We're bedazzled by so called anti aging products that promise smoother, more youthful skin. But do these lotions and potions, so temptingly packaged (and often, so astronomically priced), actually work?

That depends on how you define work.

Some over the counter anti aging products contain specific ingredients that can help skin look better temporarily, says Debra Price, M.D., clinical assistant professor in the department of dermatology at the University of Miami. The first ingredient is glycolic acid, a member of a group of fruit acids called alpha hydroxy acids (AHAs). The second is topical vitamin C more specifically, L ascorbic acid, a particular form of vitamin C.

If your skin appears dull and has lost its glow, an over the counter glycolic acid product may make it appear smoother and fresher, says Dr. Price. And when teamed with sunscreen, vitamin C gives skin extra protection against sun damage, the primary cause of wrinkles, rough work, how to use them, what they can (and ness, age spots, and discoloration.

But the weak concentrations in over the counter products cannot repeat, cannot per manently alter the skin. So while they may exfoliate and smooth your skin, they won't erase wrinkles. "If they could, they would be classified as drugs, and they wouldn't be available at the cosmetics counter," says Dr. Price.

There is one substance that research shows can permanently alter the structure of skin: tretinoin, a derivative of vitamin A and the active ingredient in Retin A and Renova. These products are drugs, so they're only available with a doctor's prescription. But they are the way to go if you want to reduce fine wrinkles and crinkles, roughness, or pigment changes such as age spots, says Nia Terezakis, M.D., clinical professor of dermatology at Tulane University School of Medicine in New Or leans.

Still, we know how irresistible those tiny jars, bottles, and perky cosmetics counter sales people can be. This guide to the hottest antiaging skin products will tell you how they can ( and can't) do, and whether to buy them over the counter or from a dermatologist or skin care salon.