BOSTON Think of it as patching up the libido.
A company-sponsored test of Procter & Gamble's Intrinsa testosterone patches for women published on Wednesday found that a high dose of the male hormone gives post-menopausal women a "modest but meaningful" boost in their sex lives after a year.
Before using the patches, the women in the study typically reported 2-1/2 satisfying sexual episodes per month.
Volunteers getting the highest dose reported 2.1additional episodes per month, a significant increase from the placebo group, which reported, on average, fewer than one extra episodes monthly.
Scores on tests measuring desire, orgasm, pleasure, and self image doubled in the high-dose group, the study found.
But the results, published in the New England Journal of Medicine, show that women who want to turn back the clock on their sex drive may have to deal with extra hair growth.
"Most of it was mild, basically," said Susan Davis of Monash University in Melbourne, Australia, who led the study. "It doesn't seem to be an issue for the women. If it had been, you would have seen much greater withdrawals from the treatment groups."
In addition, breast cancer was diagnosed in four of the 534 women in the two treatment groups, but none of the 277 placebo recipients.
Davis, in a telephone interview, said there is a good chance that the cancers were not really linked to treatment with the patches.
In any two-year study of that many women, some volunteers are likely to develop breast cancer, she said. In two of those cases, she said the cancers were clearly growing before the study began and previous tests of the patches have not uncovered a link.
In a commentary, Julia Heiman of the Kinsey Institute for Sex, Gender and Reproduction at Indiana University in Bloomington, said the results support previous findings that testosterone has positive effects on sexuality.
"At the same time, the findings suggest the need for caution in using testosterone until we understand more about its possible link with breast cancer and are better able to predict which patients are more likely to be subject to negative effects," Heiman wrote.
Davis said that when women were invited to participate in the Aphrodite study, named after the Greek goddess of love, "We were overwhelmed" with volunteers.
All of the women -- in the United States, Canada, Australia and Britain -- had reported a decrease in sex drive after menopause, which was either natural or surgically induced.
"What they say is, 'I'm too young to start feeling like this. I have a lot of years ahead in my relationship. This is important to me,'" said Davis.
Davis said that with drugs like Pfizer's Viagra, men typically get one extra satisfying episode per month. "We found women get two. So it at least matches the benefits to men."