Q: I've tried plenty of creams to get rid of stretch marks, and none has worked. Is there anything else I can do?

A: While the cause of unsightly red or white "streaks" is poorly understood, most experts agree that when the skin stretches too much (which happens during pregnancy and rapid weight gain), tightly woven collagen and elastin in the skin's dermal (middle) layer become thin or break apart. (Think of pulling a rubber band until it eventually snaps or loses its elasticity.) Fibroblasts, cells that initiate the production of collagen, also cease that function, so a dermal "scar" remains. Generally, creams don't work. One exception is prescription retinoic acid (found in Renova and Retin-A), which has been shown to improve the appearance of newer, red stretch marks. But it isn't necessarily your best option. "I've seen fair to poor results with Renova," says New York City dermatologist Dennis Gross, M.D. "It works best to regenerate sun-damaged skin; stretch marks are different."

Gross has seen impressive results with the Nd:YAG laser, however, which is typically used to stimulate collagen production to smooth wrinkles. "The laser turns on the fibroblasts to produce collagen, which helps lighten the mark," he says. While there have been no studies on the effectiveness of this laser in treating stretch marks, there have been several showing that a series of treatments with the pulsed dye laser (another type of laser) can improve both newer and more mature (white) marks. "The studies can be extrapolated to the Nd:YAG, because they're similar lasers," Gross says. "But I've seen a better response with the Nd:YAG, and it's gentler [than the pulsed dye laser]."

Though Gross has seen "good to excellent" results in many of the 300 - 500 patients he's treated, lasers don't work for everyone. That's why he tests a one-inch area of stretch-marked skin first. Those whose skin responds usually require about three treatments spaced one month apart, each of which lasts 10-30 minutes and costs about $400. But this treatment isn't without its side effects: it can cause skin to become reddish purple for up to two weeks and cannot be used on dark or tan skin because of risk of long-term discoloration.

To find a board-certified doctor in your area who performs this treatment, contact the American Academy of Dermatology at (888) 462-DERM.