Transdermal testosterone improves verbal learning and memory in postmenopausal women not on oestrogen therapy.

Objective: The aim of this study was to examine the effects of testosterone on verbal learning and memory in postmenopausal women.

Design: Randomized, placebo-controlled trial in which participants were randomized (1:1) to transdermal testosterone gel 300 mcg/day, or identical placebo, for 26 weeks.

Patients: Ninety-two postmenopausal women aged 55-65 years, on no systemic sex hormone therapy.

Measurements: The primary outcome was the score for the International Shopping List Task (ISLT) of CogState. Secondary outcomes included other CogState domains, the Psychological General Well-Being Index (PGWB) and safety variables.

Results: Eighty-nine women, median age 60 years, were included in the primary analysis. Testosterone treatment resulted in statistically significantly better performance for the ISLT (improved verbal learning and memory) compared with placebo, adjusted for age and baseline score (mean difference 1·57; 95%CI 0·13, 3·01) P = 0·03). There were no significant differences for other CogState domains or the PGWB scores. At 26 weeks, the median total testosterone was 1·7 nm (interquartile range (IQR) 1·1, 2·4) in the testosterone group and 0·4 nm (IQR 0·3, 0·5) in the placebo group.

Conclusions: The small but statistically significant effect of testosterone treatment on verbal learning and memory in postmenopausal women provides the basis for further clinical trials.