Testosterone skin patches improve sex drive in postmenopausal women

A considerable proportion of women - between 25% and 53% in fact - suffer from sexual problems, with libido taking a nosedive after the menopause as estrogen levels drop. Although low libido isn't a health problem per se, it has been shown to have a negative effect on sexual relationships and overall wellbeing.

It has been known for several years that testosterone, administered as a skin patch, improves sexual function in postmenopausal women. Previous studies on sex drive in women have only looked at the effects of testosterone in females also taking estrogen therapy, as testosterone is thought to be ineffective without concurrent estrogen administration. Long-term estrogen therapy is, however, associated an increased risk of cardiovascular disease.

A recent study by Davis et al. has now shown that testosterone patches can improve libido in postmenopausal women taking no other hormone therapy. Sponsored by Procter & Gamble, the study found that use of the company's Intrinsa testosterone patches doubled the number of satisfying sexual episodes a month in women with low libido.

The study - conducted at 65 centers in the US, Canada, Australia, the UK and Sweden - enrolled 814 women who had undergone natural or surgical (e.g. through hysterectomy) menopause and who were concerned about decreases in their levels of desire and sexual activity. These women were randomly assigned to receive daily placebo, 150 micrograms of testosterone a day or 300 micrograms of testosterone a day, which was administered via patches applied to the abdomen.

After 24 weeks of treatment, the increase in the number satisfying sexual episodes per month was greater in women receiving 300 micrograms of testosterone a day than in women receiving placebo (an increase of 2.1 episodes vs 0.7 episodes). The increase seen in women receiving 150 micrograms of testosterone a day, however, was not markedly greater than that in women on placebo (an increase of 1.2 vs 0.7 episodes). Both testosterone therapy groups showed a greater increase in sexual desire than the placebo group and a more notable decrease in libido-related personal distress.

The number of reported side effects throughout the 52-week study period was similar in all three groups, although there was a higher incidence of unwanted hair growth in the women receiving 300 micrograms of testosterone a day. Four women receiving testosterone were diagnosed with breast cancer compared with none in the placebo group, but at least one case was thought to have developed before the initiation of testosterone therapy and the other cases were put down to chance.

Speaking to CNN, Dr Sheryl Kingsberg, one of the coauthors of the study, said, "Although the change in activity is modest, that's something that is appropriate and I think most women would be more than happy with it. They wanted to return to the level of desire they had in their premenopausal years, and that's what they got."

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Davis SR et al. for the APHRODITE Study Team (2008). Testosterone for Low Libido in Postmenopausal Women Not Taking Estrogen N Engl J Med 359 (19): 2005-2017 PMID: 18987368