Though stretch marks can't be prevented, frequent moisturizing may make them less prominent. When they do appear, your best bet is to address them when they are red or purple. A couple of sessions with a pulsed-dye laser will remove the redness. The marks will still turn smooth and white, but if they're treated early, they'll be less obvious. For older marks, you can lightly even out the texture with a topical retinoid. For a more intensive treatment, opt for a few sessions with a fractionated nonablative laser, which can diminish white stretch marks by about 50 percent, says New York City dermatologist Julie Karen, MD.