Getting your dose of vitamins used to mean popping a few pills. Now it also means slathering them on your skin - in the form of moisturizers or high-potency serums and creams. To help you choose from the almost dizzying array of vitamin-enriched products available, Scarsdale, N.Y., dermatologist Amy Newburger, M.D., offers this advice: "Pick the one thing that concerns you the most about your complexion -- fine lines, a blotchy complexion, dull-looking skin, whatever it is." Then look for the right topical vitamin-based product to target that problem, using the following guide to help you.

Problem: Fine lines and wrinkles

Solution: Vitamin A

Rather than denying the tiny signs of wear that eventually creep up on all of us, try over-the-counter products with retinoids, as the many chemical cousins of vitamin A are known. (Look for retinol on the label.) These are less-powerful versions of the well-known prescription products Retin-A and Renova.

A recent study in the Journal of Investigative Dermatology reported that a topically applied preparation of retinol (with as little as 1 percent of the active ingredient) can help stimulate production of collagen, a protein that plumps and thickens the skin, helping smooth wrinkles. Because most over-the-counter products contain a fraction of that amount (anywhere from 0.05-0.5 percent), "they won't penetrate the skin as easily or work as quickly as Retin-A or Renova, but they can penetrate and they can work," Newburger says. "It may just take a little longer (two to three times as long) to see results."

Look for retinoids in products like L'Oréal Plénitude Revitalift Oil-Free Lotion ($12;, Neutrogena Healthy Skin Anti-Wrinkle Cream ($13; 800-421-6857), and Clarins Renew-Plus Night Lotion ($49.50;

Problem: Sensitive skin that lacks a healthy glow

Solution: Vitamin B3

For those who find exfoliators like glycolic and salicylic acid too harsh for their complexion, the newest creams with vitamin B3 , or niacinamide (a derivative of niacin) are showing promise. Unlike other chemical exfoliators, B3 is less acidic -- causing little to no irritation, says Zoe Draelos, M.D., clinical associate professor of dermatology at Wake Forest University School of Medicine in Winston-Salem, N.C. The only problem with B3: This ingredient is so new that only industry studies funded by manufacturers have been done on it; results have not yet been duplicated in clinical, independent settings. Look for B3 in Olay Total Effects ($20; and Lancôme Vinéfit ($37.50;

Problem: Sun damage (freckles, hyperpigmentation and fine lines)

Solution: Vitamin C

The real strength of vitamin C, according to an October 1999 study in the Journal of Applied Cosmetology, is in its effectiveness as an antioxidant -- a substance that squelches free radicals (unstable molecules created as a result of pollution, smoking and sun exposure). These free radicals are implicated in the development of everything from hyperpigmentation (freckles and dark spots) to skin cancer. But the key to effectiveness -- as this study and others have found -- is the use of a concentration of 10 percent vitamin C or higher -- an amount many experts consider critical to a product's effectiveness.

Use it every morning (in addition to sunscreen) to help protect against further sun damage and reduce discoloration, says New Orleans dermatologist Mary Lupo, M.D. Try C-based products like Peter Thomas Roth Power C 20 Anti-Oxidant Serum Gel ($85; or SkinCeuticals Primacy Serum 20 ($95; 800-811-1660).

Problem: Dry, rough skin

Solution: Vitamin B5 or vitamin E

Both vitamins are known for their moisturizing abilities. And, like C, vitamin E is a potent antioxidant, but -- here's the bad news -- not in the concentrations used in most over-the-counter products. It's also not the wound healer we all thought it was. A recent University of Miami School of Medicine study found that when applied to wounds, it did not promote healing. All this research means is that you should use vitamin E (and B5) for moisturizing, not anti-aging or wound healing. Opt for vitamin B5 creams or serums if you have sensitive skin as vitamin E-based creams may cause irritation. Products formulated with vitamin B5: Cellex-C Hydra 5 B-Complex ($60; 800-CELLEX-C) and with vitamin E: RoC Chronoblock ($18; 800-ROC-1964), Origins Have a Nice Day ($28.50; 800-ORIGINS), or Chanel Précision Hydra Sérum ($75; 800-550-0005).

Problem: Dark undereye circles

Solution: Vitamin K, retinol and/or vitamin C

Sometimes, no matter how many hours of Z's you get, you can't rid yourself of those dark circles beneath your eyes. Some experts believe the cause may be tiny, leaking capillaries under the skin. And since vitamin K is known for its ability to aid in blood coagulation, it makes sense that it may help correct the discoloration. A recent study in Cosmetic Dermatology backs up the theory, concluding that topical application of vitamin K creams in concentrations of 1 percent mixed with 0.15 percent retinol may significantly lighten dark undereye circles. (Side effects include dryness and slight irritation.) Vitamin C also works well, Newburger adds. Try creams with both ingredients, like St. Ives Dark Circle Diminisher ($9;, Avon Lighten Up Undereye Treatment ($15; or Peter Thomas Roth Power K Eye Rescue ($100; 800-PTR-SKIN).

Skin supplements: Getting your daily dose

It's hard enough to remember to take our daily vitamins like a multi-, calcium and vitamin E. Now we're being bombarded by skin-care companies with special oral skin supplements -- vitamins said to help build healthy, younger-looking skin. But can these pills really keep your skin healthy?

"Certain nutrients and antioxidants, like vitamin C and vitamin E, do help protect the skin against photoaging (damage caused by sun exposure)," explains Jeffrey Blumberg, Ph.D., professor of nutrition at the School of Nutrition Science and Policy at Tufts University. "But there is no compelling data that suggests the larger doses you get in so-called skin supplements improve the skin any more."

Jo-Ann Heslin, a registered dietitian in Long Island, N.Y., agrees, adding that the body has a standard system for distributing vitamins. "Your body isn't going to release more vitamins to the wrinkles around your eyes just because you take more," she says.

While megadosing on vitamins is wasteful at best, depending on the vitamin, it can also be harmful. Excess fat-soluble vitamins such as A and E are stored in your tissue and can cause everything from headaches to hair loss.

Both Heslin and Blumberg agree that a well-balanced diet and a multivitamin will give you most of what you need to be healthy inside and out. "Given the diet of the public today, a multivitamin is an 'insurance plan' for good health," Heslin says, "and good health will -- now and in the long run -- definitely benefit your skin."