Lack of sexual desire among women is not something new. Just last week, a study by researchers from Massachusetts General Hospital found that an estimated 40 percent of all women surveyed (31,500 American women 18 and older) said they had sexual issues, but only 12 percent of them were worried about their sexual problems.

“Sexual problems are common in women, but problems associated with personal distress, those which are truly bothersome and affect a woman's quality of life, are much less frequent,” said study leader Dr. Jan Shifren, of Massachusetts General's Obstetrics and Gynecology Service at the time.

No drug treatment is specifically approved for this kind of problem, but the situation is going to improve, as new research in the November 6 New England Journal of Medicine suggests that boosting levels of male sex hormone testosterone can help postmenopausal women with low libido get back in the mood.

The study was paid for by Proctor & Gamble Pharmaceuticals, the manufacturer of the testosterone patch, Intrinsa.

The patch is already available in Europe to treat lack of sexual desire in women, but the US Food and Drug Administration turned down the manufacturer’s request for approval in December 2004, citing a lack of long-term safety data.

The new study involved women who had undergone surgically induced menopause and women who had undergone menopause naturally, all of whom were diagnosed with low sexual desire.

The 52-week study included 814 women experiencing troublesome low sexual desire or function. They were divided in three groups: the first group wore patches delivering 300 micrograms of testosterone per day, the second wore 150-microgram patches and the third wore placebo patches with no testosterone.

Women in the study, who averaged 54 years old, were asked to keep a weekly diary of sexual episodes and note which ones they considered “satisfying.”

The study found after 24 weeks, women in the 300 microgram group of testosterone reported an average of 2.1 satisfying sexual episode during a four-week period, compared to 1.2 sexually satisfying episodes for those on the lower dose and just 0.7 satisfying episodes for women on the placebo.

“This is the first study to show that when used alone, testosterone administered by a skin patch significantly improves sexual well-being in postmenopausal women,” the lead author, Dr. Susan R. Davis of Monash University in Prahran, Australia, said in a statement.

According to the study, both doses of testosterone were associated with an increase in sexual desire. The increase in sexual desire though came with unwanted face hair growth as the most significant side effect, but the women in the study didn’t find it troubling enough to stop taking testosterone.

Four women in the 300-microgram patch group developed breast cancer during the follow up period compared to no woman in the placebo group. However Davis said two of the breast cancers appear to have been present, but missed, before the beginning of the trial, while a third cancer occurred in a woman who had taken estrogen hormone therapy for 27 years. Long-term estrogen treatment has been linked to an increased risk of cardiovascular disease and breast cancer in older women.

Given the results of the study, Davis said the testosterone patch “is probably safe.”

A spokesman for Procter & Gamble did not want to comment whether the company would seek FDA approval for the testosterone patch.