"It doesn't work for everybody, but when it works, it works nicely," said Dr Sheryl Kingsberg of University Hospitals of Cleveland in Ohio, the study's lead author.
Women in the study who said the patches offered them a "meaningful benefit" said they would keep on using them. But women who said the patches didn't help said they wouldn't.
"There has been a lot of criticism that the pharmaceutical industry is really pushing medicines on women and convincing them to take something that they don't really need," Kingsberg said. The findings show, she added, that "women are a lot smarter than these critics give them credit for."
Six-month trial
Kingsberg and her team analysed the results of a six-month trial of testosterone patches in 132 women reporting a lack of sexual desire that had caused personal distress or relationship problems.
All were in "surgical menopause," meaning their ovaries had been removed, resulting in low production of sex hormones, including testosterone.
Proctor & Gamble Pharmaceuticals made the patches and funded the study.
Fifty-two percent of the 64 women on the patches said they experienced a meaningful benefit, compared to 31 percent of the 68 women on placebo.
The women who reported a meaningful benefit said they were engaging in 4.4 more episodes of "satisfying sexual activity" every four weeks, compared with 0.5 episodes more per month for women who reported no benefit.
They also went from "seldom" to "sometimes" feeling desire, while their level of personal distress dropped from feeling distressed "often" to "seldom."
However, women who reported no benefit from the patches also showed no significant change in desire or distress, still "seldom" feeling desire and "often" feeling distress.
Not clear why works for some, not others
More than 85 percent of the women who reported the patches helped said they were "probably or definitely" interested in continuing to use them, while over 90 percent of those who reported the patches didn't help said they were "probably or definitely" not going to keep using them.
It's not clear why some women benefit from the patches and others don't, Kingsberg said; perhaps their sexual problems aren't related to drive, or don't respond biologically to the hormone.
But the findings show, she added, that a woman will know within three months whether or not the product works for her.
The FDA has not approved any type of testosterone therapy for females, she added, but it's estimated that as many as one in five US testosterone prescriptions are written "off-label" for women. – (Anne Harding, ReutersHealth)
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