Male Sex Hormone Gets Women in the Mood
But Testosterone Safety Questions Remain
Nov. 5, 2008 -- Low sexual desire is a common complaint among women, but there is no drug treatment specifically approved for the problem.
Now, new research in the Nov. 6 New England Journal of Medicine suggests that boosting levels of the male sex hormone testosterone can help postmenopausal women with low libido get back in the mood.
But questions remain about the treatment's safety.
An increasing number of women in the United States have been using testosterone off-label to treat problems with sexual desire, arousal, and achieving orgasm.
The new study examined the safety and effectiveness of an experimental testosterone patch developed specifically for the treatment of low sexual desire in women. The study was paid for by Proctor & Gamble Pharmaceuticals.
Testosterone Patch Revisited
The company sought fast-track approval for a 300-microgram patch, which it calls Intrinsa, in 2004, specifically for women who had had declines in testosterone levels as a result of having surgically induced menopause.
But in December of that year, a 14-member FDA advisory committee unanimously rejected the request, citing concerns about the lack of long-term safety data and off-label use.
The new study included women who had undergone surgically induced menopause and women who had undergone menopause naturally, all of whom were diagnosed with low sexual desire.
And unlike most previous studies, the women did not take estrogen or estrogen plus progesterone while using the testosterone patch.
The 52-week study included 814 women with sexual desire disorder, characterized by troublesome low sexual desire or function.
About a third of the women wore patches delivering 300 micrograms of testosterone per day, another third wore 150 microgram patches, and the rest of the women wore placebo patches with no testosterone.
More Satisfying Sex
The women were asked to keep sexual encounter diaries, and researchers used other established measures to assess sexual response during the six-month evaluation phase of the study.
They found that compared to placebo users, the women who used the 300 microgram patch reported significant improvements in sexual functioning, including desire, arousal, orgasm, and pleasure. This was not the case for women who wore the lower-dose testosterone patch.
Women who wore the higher dose patch had about two more satisfying sexual experiences over a four-week period than women in the placebo group. Women in the lower-dose group had one more.
At the start of the study, about half of all sexual episodes were rated as satisfying. By week 24, 78% of the episodes in the higher-dose testosterone group were rated as satisfying, compared with 65% in the placebo group.
Lead researcher Susan R. Davis, MD, PhD, tells WebMD that the findings show that testosterone is an effective treatment for low sexual desire in women without adding estrogen treatment to the mix.
This is important because long-term estrogen treatment has been linked to an increased risk of cardiovascular disease and breast cancer in older women.
"Unlike men, women tend to continue to have sex even when it is not particularly satisfying for them," she says. "So if they are having sex five times a month on average and they can enjoy it twice as often, that could make a big difference."