Treatment with a testosterone patch produced modest improvements in sexual function in postmenopausal women. However, there was an excess of breast cancers in the active treatment group.

A one-year double blind study was carried out in 814 postmenopausal women with ‘hypoactive sexual desire syndrome’ comparing placebo patches with patches delivering either 150 or 300 µg testosterone daily.

At baseline the average number of sexually satisfying encounters over the previous four weeks was around 2.5. At 24 weeks the four-weekly frequency of satisfying sexual encounters rose in all three groups: by 0.7 for placebo, 1.2 in the 150 µg group and 2.1 in the 300 µg group (p<0.001 for placebo compared with 300 µg testosterone). In percentage terms, by week 24 the number of sexual encounters that were satisfying was 65% for placebo and 78% with 300 µg testosterone. No differences in results were seen between women who had undergone natural or surgical menopause although oopherectomy status was not stated. After the menopause most androgens are ovarian in origin.

Not surprisingly androgenic side-effects were noted more commonly in the women exposed to testosterone, especially with the higher dose. Acne and voice change were no more common but hair growth seemed modestly increased in testosterone users. Vaginal bleeding occurred in 10.6% of unhysterectomised women on the 300 µg patch, this was four times more common than with 150 µg testosterone (2.7%) or placebo (2.6%). Investigation in these women included endometrial biopsy. Four cases of mild clitoral enlargement developed all of which resolved after cessation of testosterone therapy. Four cases of breast cancer were identified in the women given testosterone, although one woman retrospectively reported symptoms that had been present before randomisation. There were no cases of breast cancer in the placebo group.

The three principal areas to consider when enquiring about sexual function relate to desire or libido, arousal and climax or orgasm. Diminished libido is common after the menopause whether it is natural or surgically induced and is identified subjectively if a woman complains of a decrease in sexual desire or activity which causes distress. Physical sexual arousal is thought to be oestrogen driven whereas sexual desire or libido is androgen driven.

It can be difficult to determine whether such behavioural and emotional feelings are part of the natural development that is a feature of life and ageing or whether they truly represent a disease state in need of treatment; this is the crux of the ‘disease mongering’ debate.

This study showed testosterone supplementation did have a modestly greater effect than placebo on libido but it did not come without risk. The authors point out that additional data are needed to assess the long-term safety of testosterone use in women with oestrogen depletion. If oestrogen replacement presents problems in practice then testosterone supplementation therapy seems to present more.