Acne cream works as spot remover.

Tretinoin (trade name Retin-A), a prescription skin cream for acne, fades liver spots without causing any serious side effects, according to a study led by John J. Voorhees at the University of Michigan Medical Center in Ann Arbor. Furthermore, the effect appears to be permanent, the researchers report in the Feb. 6 NEW ENGLAND JOURNAL OF MEDICINE.

Liver spots form when long-term exposure to the sun causes cells beneath the skin surface to overproduce pigment, which builds up and creates a blotch. Although the dark, freckle-like marks are harmless, they're difficult to remove. Each year, thousands of people in the United States undergo minor surgery to get rid of them.

Voorhees and his group treated liver-spot patients with the cream every day for 10 months. After one month, some spots began to fade. By the end of the study, more than 80 percent of each patient's spots had faded, some completely. None of the spots returned in the six months following the study. The only side effects from the treatment were some cases of temporary rashes and scalling, the team reports.

Tretinoin not only inhibits pigment production, but also rapidly transports accumulated pigment to the skin surface, says Albert M. Kligman, a dermatologist at the University of Pennsylvania in Philadelphia. "You're dumping [pigment] out faster than it can accumulate," he explains.

Kligman says the new finding comes as no surprise to most dermatologists, who had noticed the spot-removing effect before, but Voorhees' study is the first to confirm that effect.