Testosterone is an essential female hormone. It is an obligatory precursor for extra-gonadal estradiol production, particularly in women with spontaneous or surgical menopause, and has key direct androgenic genomic and non-genomic effects. Testosterone levels decline with age from the late reproductive years and appear to reach a nadir in the 7^th decade of life. Testosterone levels are positively associated with sexual function in premenopausal and postmenopausal women, and multiple randomised placebo-controlled trials have shown that testosterone therapy can be effective for the treatment of female sexual dysfunction in both late premenopausal and postmenopausal women. Lower free testosterone in premenopausal women are associated with low IVF response and studies are underway to determine the effectiveness of testosterone pre-treatment in IVF cycles.

In the brain, testosterone exhibits neuroprotective effects and clinical trials suggest exogenous testosterone enhances cognitive performance in postmenopausal women. Low testosterone is associated with bone loss in premenopausal and postmenopausal women, and for older women a greater risk of hip fracture and sarcopenia. Observational studies implicate testosterone as having favourable cardiovascular effects measured by surrogate outcomes, however associations between endogenous testosterone and cardiovascular disease risk, and total mortality, particularly in older women are yet to be established. While attention is usually given to estrogen replacement for women experiencing primary ovarian insufficiency, or natural or surgical menopause, testosterone therapy also merits consideration.