Since men began popping a pill for their sexual woes, women have wondered if there might be a similarly easy solution for one of their most common complaints, a low libido. The testosterone patch, Intrinsa, could increase some women's sex drive, according to a new study in the Archives of Internal Medicine. The patch has not yet been approved by the FDA, though the manufacturer, Procter & Gamble, hopes to market it someday and the drug remains in clinical trials. Late last year, an FDA panel rejected the company's application, citing the drug's unknown long-term effects.

Intrinsa is meant to boost testosterone levels by administering synthetic doses of the hormone through a patch worn on a woman's skin. Often women who have gone through menopause, either naturally or by having their ovaries surgically removed, have a significant drop in testosterone levels. Because testosterone is one of the hormones that regulate sexual desire and responsiveness, drops in this hormone can stall a woman's sex drive.

This study reported that women who had gone through surgically induced menopause experienced more desire to have sex and more sexual arousal after using the patch for six months. Researchers tried three different doses of hormones during the study; women wearing the middle dose showed the biggest improvements. The lowest dose did not have a significant effect, and the highest dose improved women's sex drive no more than the middle dose. Studies on using the patch for natural menopause have shown positive results, though the data have not yet been peer-reviewed.

Robert Vigersky, an endocrinologist at Walter Reed Army Medical Center who commented on the study in the journal, says the dosage results were "surprising" and could make it difficult for clinicians to determine when the patch is effective. He also says that previous studies on Instrinsa have been inconsistent in showing which component of sex—sexual desire or frequency of sex and orgasm—the patch actually helped.

However, lead researcher Glenn Braunstein, an endocrinologist at Cedar-Sinai Medical Center in Los Angeles, says that testosterone can help women who just don't feel like having sex. Unlike the mechanical problem that Viagra helps to fix, women's sexual functioning is all about getting in the right frame of mind. In women, he says, "testosterone is really more important for mood. Low libido is really a mood issue."