These thin scars on the stomach, hips, breasts, or butt usually start out red and then lighten within a year. "Whether you get stretch marks depends a lot on genetics and how quickly you gain weight," says David J. Goldberg, M.D., director of laser research in the department of dermatology at Mount Sinai School of Medicine, in New York City. The earlier you treat them, though, the better your chance of fading them.
What works: Retin-A cream. It's most effective on newer, red marks, but steer clear of it if you're pregnant or nursing. "Retin-A builds up collagen, the firming fibers that were broken when skin was stretched," Dr. Jaliman explains. Side effects include temporary redness and flaky, dry skin. Microdermabrasion -- a procedure in which tiny crystals are blasted against your skin to remove the top layer and stimulate collagen production -- can treat older stretch marks. In addition, the FDA recently approved a new laser treatment that adds pigment to older, lighter stretch marks so they blend into surrounding skin.
What doesn't: Vitamin K creams. "Varicose veins are too deep for a topical cream to reach and provide any benefit," Dr. Jaliman says.
Quickest fix: Pants and long skirts. Or camouflage veins with waterproof makeup, like Dermablend or Era Face, or with self-tanning lotion. "The veins will appear less blue against tanned skin," McEvoy says.