An Australian led study found that using testosterone patches helped to increase sex drive in post-menopausal women with low sex drive who were not on hormone replacement therapies.
The research was led by principal investigator Susan Davis who is Professor of Women’s Health in the Department of Medicine at Monash University, Victoria, and published in the 6th November issue of the New England Journal of Medicine. The study was supported by Procter and Gamble Pharmaceuticals USA.
“What we have found is that treatment with a patch delivering 300 micrograms (ug) of testosterone each day results in meaningful improvement in sexual function in postmenopausal women with low libido who are using no other hormone therapy,” said Davis .
The study is thought to be the first in the world to show that administering testosterone on its own through a skin patch can significantly increase the sexual wellbeing of women who seek medical help for loss of sexual desire following the menopause, something that is not uncommon said Davis.
There are studies that show testosterone works for women who are also taking estrogen, but not many women want to take estrogen. There is evidence that long term treatment with estrogen can increase the risk of cardiovascular disease and breast cancer in post-menopausal women.
Davis said that women often worry about using testosterone and what side effects there might be, but she said it was important to realize that testosterone is also an essential hormone in the female human body. For instance, many women past the menopause are likely to have more testosterone in their bloodstream than estrogen.
“In this study few side effects were documented,” said Davis. Some women reported extra unwanted facial hair but this was not enough to make them want to come off the treatment.
The study was a double-blind, placebo-controlled, 52-week trial involving 814 post-menopausal women with hypoactive sexual desire disorder treated at 65 different centres in Australia, Canada, Sweden, the UK and the US.
The researchers randomly assigned the women to receive a patch delivering 150 or 300 ug of testosterone daily or a placebo.
The women were asked to keep structured diaries of their sexual episodes. These accounts, together with other assessments gave the researchers a range of satisfaction measures covering qualities like arousal, level of desire, orgasm and pleasure.
The primary measure of efficacy was the change between the start of the study (baseline) and 24 weeks later in the 4-week frequency of satisfying sexual episodes as reported by the women. Safety was evaluated for 52 weeks, and a subgroup was followed for another year.
The results showed that:
- At the start of the study, on average the women reported that about 50 per cent of all sexual episodes were satisfying.
- After 24 weeks, the women in the higher testosterone dose group reported that about 78 per cent of sexual episodes were satisfying compared with 65 per cent in the placebo group.
- After 24 weeks, the 300 µg per day testosterone group reported an average increase of 2.1 extra satisfying sexual episodes per month compared with 0.7 in the placebo group (P
Davis and colleagues concluded that:
“In postmenopausal women not receiving estrogen therapy, treatment with a patch delivering 300 µg of testosterone per day resulted in a modest but meaningful improvement in sexual function.”
However, they also noted that:
“The long-term effects of testosterone, including effects on the breast, remain uncertain.”
In an accompanying editorial, Dr Julia R Heiman, director of the Kinsey Institute for Sex, Gender and Reproduction, urged caution about adminstering testosterone to address sexual desire problems in women. As the researchers themselves noted, the link with breast cancer is not clear, she wrote, and we don’t understand enough to be able to predict which patients are more likely to have negative reactions.
Davis said in a press statement that research on the safety issues was under way, involving more women over a longer period.
Testosterone therapy is not currently an approved treatment for women in Australia.
“Testosterone for Low Libido in Postmenopausal Women Not Taking Estrogen.”
Davis, Susan R., Moreau, Michele, Kroll, Robin, Bouchard, Celine, Panay, Nick, Gass, Margery, Braunstein, Glenn D., Hirschberg, Angelica Linden, Rodenberg, Cynthia, Pack, Simon, Koch, Helga, Moufarege, Alain, Studd, John, the APHRODITE Study Team.
N Engl J Med, Volume 359, No 19, pages 2005-2017, 6 November 2008.
Sources: NEJM, Monash University.
Written by: Catharine Paddock, PhD.