Skin anti-ager #1: Focus as much on what you put in your body as on what you put on your skin.

You might expect a dermatologist to emphasize only skin-care products and techniques, but Madfes says that younger skin starts with the nutrients that reach it from inside the body. The skin is the body's largest organ, after all. So diet directly affects how you visibly age.

How to do this:

• Take a vitamin D supplement. Madfes recommends 1,000 IUs per day.

• Eat plenty of omega-3 and omega-6 fatty acids. Ideally they should come from natural sources, including olive oil, ground flaxseed, and fish such as salmon. Fish-oil supplements are another source of these important fats, which help protect the moisture barrier. This is the protective top layer of skin that keeps moisture in but tends to thin as you age, causing dry skin.

• Drink water -- in all its forms -- all day long. A liter a day is a good minimum start, Madfes says. Different body types, such as athletes, need more. Count green tea and coffee in your daily total, but go easy on the alcohol. Red wine does contain beneficial antioxidants, but it can also dilate blood vessels, contributing to the ruddy-faced skin inflammation called rosacea that tends to strike women in midlife.

• Cut way back on processed foods and sugars (another reason to watch the wine intake). They promote inflammation, a biochemical process that damages the normal production of dermal cells.

Skin anti-ager #2: Halve your sun exposure.

If you've heard a version of this one before, it's because dermatologists agree that UV exposure is the number-one skin-ager out there. Sun damages elastin and causes a loss of collagen, which translates to drooping, a lost jawline, and wrinkles. It also adds discoloration and roughens texture. Not least, UV rays are the main cause of skin cancers, an aging risk that goes beyond the mere cosmetic.

"Simply saying, 'Stay out of the sun!' isn't practical, though," Madfes says. "So I tell patients to just try to cut your exposure in half -- that seems more doable."

How to do this:

• One word: sunblock. Use a full tablespoon of sunscreen with a sun-protection factor (SPF) of at least 30 on your face, spreading it to your neck and ears. Know that older skin tends to be more vulnerable to the effects of the sun than younger skin.

• If you tend to forget sunscreen, try the newish makeup bases and moisturizers with UV-protection built in. On the downside, you might not get the optimum amount of SPF, but Madfes says that the plus for many women is that at least they remember some protection every day -- which is better than going without.

• Walk on the shady side of the street. "You really can decrease your exposure with little things," Madfes says.

• Wear UV-protective clothing. A host of new apparel blocks UV rays while wicking away moisture, making these clothes especially good for outdoor exercise.

• Exercise outside in the early morning or late afternoon. If you can, avoid sun between 10 a.m. and 4 p.m., when UV rays are most potent.