4 Decades of Beautiful Skin

In Your 20s...

Attention, dewy young beauties: This is the most important decade for your skin. The way you care for it now will determine what it will look like for the rest of your life. Because it's probably at its healthiest, with great collagen support, your skin is supple. Whatever sun damage you may have has not yet started to show. Lucky you: Light reflects off the plump surface of your cheeks, giving you a healthy glow.

The number one complaint among women in their 20s is acne, says Ranella Hirsch, MD, president-elect of the American Society of Cosmetic Dermatology & Aesthetic Surgery. (See "I'm Too Old for Acne!") But it's largely avoidable. Most 20-somethings break out because they use dehydrating products that strip their skin of natural oils, says Hirsch. This causes oil glands to overproduce, resulting in pimples.

Your No-Fail Plan

Use gentle products, and focus on damage prevention. "You don't need antiwrinkle creams or microdermabrasion in your 20s," says Ranella Hirsch, MD, president-elect of the American Society of Cosmetic Dermatology & Aesthetic Surgery.

Cleanser: If you have normal skin, you need to wash it only before bed, says Lupo. Use a mild cleanser—either a gel, if your skin is oily, or a milky one, if it's dry.

Moisturizer: Pick a brand, any brand. But be absolutely sure that your moisturizer has SPF 15 or 20, and that it gives you both UVA and UVB protection. Apply it all over your face and on your neck and chest, says Lupo. (This is critical no matter what your age.)

Nighttime treatment: Use a hydrating fluid or an oil-free moisturizer. Many dermatologists recommend starting on the vitamin A-derivative prescription retinoids (like Retin-A, Tazorac, and Avage)—the gold standard for reducing fine lines, stimulating collagen, and treating acne—or products containing the less potent, over-the-counter retinol. Before bed, apply a pea-size amount all over your face and right up under your eyes, says Hirsch; then you don't need an eye cream.