SAN FRANCISCO – Postmenopausal women showed a modest improvement in verbal learning and memory after being on testosterone gel for 6 months, according to researchers from Monash University in Melbourne.
Ninety healthy, cognitively normal women aged 55-65 years were randomized in the trial to 0.22 g transdermal testosterone gel (LibiGel) daily, or to placebo.
At the end of 26 weeks, women on testosterone scored 1.6 points better on the 48-point International Shopping List Task, meaning that they recalled a total of 1.6 more words while being read three lists containing 16 words each. The placebo group improved a bit from the mean baseline score of 33.7 words, as well, but not quite as much. There were no other significant differences in well-being and cognitive function.
Dr. Susan Davis
Lead investigator Susan Davis, chair of Women’s Health at Monash, said the finding, and a few similar ones from previous work, provide "evidence for the conduct of large-scale clinical studies" to see if testosterone can help preserve cognition as women age. "Possibly, there’s a beneficial effect, but it does need to be explored."
"Women complain of loss of memory after menopause. ... We hypothesize that women after menopause are not operating in their optimum cognitive range." That could have something to do with naturally declining levels of testosterone; supplementation could be more about "optimizing normality rather than treating a disease," she said at the Endocrine Society’s annual meeting.
There’s evidence, mostly from trials in men, that the hormone has "an important role in brain function," she said.
Mean serum total testosterone was at the lower limit of normal in both groups at baseline; it increased a mean of 1.9 nmol/L in the treated group and remained largely unchanged in the placebo group. Women on systemic hormone therapy were excluded from the study.
Dr. Davis did not mention any adverse events but noted that the literature on testosterone therapy in women "has not shown anything sinister" with physiologic doses.
She was the lead investigator in a trial of 814 women that found a modest benefit for testosterone patches on libido. Breast cancer was diagnosed in four women treated for up to 2 years in the study, but none in the placebo group; vaginal bleeding was more common in the treated group, as well (N. Engl. J. Med. 2008;359:2005-17).
Dr. Davis is the principal investigator and a scientific board member for BioSante Pharmaceuticals, makers of the testosterone gel used in the study. She is also an investigator for and consultant to Trimel, maker of an intranasal testosterone gel. The work was supported by BioSante.