Understanding Testosterone Levels in Females
Females have small amounts of testosterone (T), with levels ranging from 0.3-1.8 nmol/L, compared to 8.0-28 nmol/L in males. Testosterone is produced by the ovaries and adrenal glands, either directly or from precursor hormones like DHEA and androstenedione. In females, testosterone plays a role in musculoskeletal health, sexual health, bone health, and cognitive function.
Testosterone Production and Decline
Testosterone peaks during adolescence (hello, teenage acne!) and then gradually declines through to menopause. Interestingly, testosterone levels increase again around age 70 to pre-menopause levels.
Challenges in Measuring Female Testosterone
Measuring testosterone in females is challenging for two main reasons:
- The assays used are inaccurate at female levels, and more accurate mass spectrometry is expensive and not routine.
- Testosterone is produced within tissues from precursors, so serum levels do not reflect actual testosterone activity in the body.
This means there is no specific level that categorizes “testosterone deficiency” in females.
Factors Affecting Testosterone Levels
Any condition or medication that affects the ovaries or adrenal glands can decrease testosterone levels. Examples include the pill, adrenal insufficiency, functional hypothalamic amenorrhea (FHA), prednisolone, or other glucocorticoids.
Testosterone Treatment in Females
There have been numerous well-powered studies examining the effects of testosterone treatment in pre- and post-menopausal females. The only condition where testosterone has shown clear benefits over placebo in randomized controlled trials (RCTs) is post-menopausal hypoactive sexual desire disorder (HSDD) with distress.
Clinical Experience and Recommendations
Post-menopausal women often share that they have sex with their partner out of love but lack interest or arousal, and sex is often physically uncomfortable. Consequently, I love prescribing testosterone, sometimes combined with hormone replacement therapy (HRT) or vaginal estrogen, as sex should be enjoyable and not painful!
I have also prescribed testosterone to women on the pill with low libido, but this is based on clinical experience rather than evidence, and the effect may just be placebo.
Current Evidence and Treatment Options
So far, there is no evidence supporting testosterone treatment for general well-being, bone health, body composition, or cognitive function. In Australia, we have a female-specific testosterone cream called AndroFeme, which is applied daily. Testosterone pellets or injections should not be used due to the risk of excess dosage, and compounded testosterone has not been tested for safety or efficacy.
Monitoring and Efficacy
Testosterone levels need to be monitored, and treatment generally takes 8-12 weeks to show efficacy. 😊