When most people hear "testosterone," they think of men. But testosterone is actually the most abundant active sex hormone in women too - produced in greater quantities than estrogen throughout most of a woman's life. And when levels decline or become imbalanced, the effects can be just as profound.
Testosterone's Role in Women: Far Beyond Reproduction
Testosterone in women is produced by the ovaries, the adrenal glands, and through peripheral conversion of other androgens. While women produce roughly one-tenth the amount men do, this smaller quantity can play an outsized role in health:
- Energy and vitality: Testosterone can support mitochondrial function and overall energy production
- Muscle mass and strength: Adequate levels can help maintain lean body mass and metabolic rate
- Bone density: Testosterone can work alongside estrogen to protect against osteoporosis
- Cognitive function: Testosterone receptors are found throughout the brain, and adequate levels can support memory, focus, and processing speed
- Libido and sexual function: Testosterone can be the primary driver of sexual desire in women
- Mood regulation: Low testosterone can be associated with depression, apathy, and decreased motivation
- Cardiovascular health: Emerging research may suggest testosterone can have protective effects on blood vessel function
Why Testosterone Gets Overlooked in Women
Despite its importance, testosterone is rarely tested in women unless they present with overt signs of excess (like facial hair or severe acne). This can create a major blind spot: low testosterone in women can go undiagnosed, even when symptoms are staring clinicians in the face.
The reasons for this gap include:
- No FDA-approved testosterone therapy for women in the United States, which reduces clinical attention
- Outdated belief that testosterone is irrelevant to women's health
- Poorly defined reference ranges that vary wildly between labs
- SHBG confounding: Total testosterone can appear normal while free (active) testosterone may be critically low
Symptoms of Low Testosterone in Women
Low testosterone in women can produce a constellation of symptoms that can be attributed to depression, aging, or "just stress":
- Persistent fatigue that does not improve with sleep
- Low or absent libido - the most classic symptom
- Difficulty building or maintaining muscle despite regular exercise
- Unexplained weight gain, particularly increased body fat relative to muscle
- Brain fog and difficulty concentrating
- Depressed mood, apathy, or loss of motivation
- Decreased sense of well-being
- Joint pain or muscle weakness
- Thinning hair (though excess testosterone can cause it too - this can reflect a complex balance)
Free Testosterone vs Total Testosterone: Why It Matters
This distinction is critical and frequently misunderstood. Total testosterone measures all testosterone in your blood, but a large portion is bound to proteins - primarily sex hormone binding globulin (SHBG) and albumin. Only the unbound fraction, called free testosterone, is biologically active and available for your cells to use.
A woman can have a "normal" total testosterone level while her free testosterone may be extremely low if her SHBG is elevated. This can be particularly common in women taking oral contraceptives, which can dramatically increase SHBG.
The SHBG Connection
SHBG is a protein produced by the liver that binds to sex hormones and reduces their bioavailability. Factors that can increase SHBG include:
- Oral contraceptives (the most common cause in premenopausal women)
- Hyperthyroidism
- Liver disease
- Low caloric intake or eating disorders
- Aging
Factors that can decrease SHBG include:
- Insulin resistance and PCOS
- Hypothyroidism
- Obesity
- High-dose corticosteroids
Testing both total testosterone, free testosterone, and SHBG together can provide the complete picture. Testing total testosterone alone can be misleading.
Age-Related Testosterone Decline
Women's testosterone levels can peak in the early 20s and decline steadily throughout life. By age 40, a woman's testosterone level can be approximately half of what it was at age 20. By menopause, levels may be 75% lower than their peak.
This decline can happen gradually:
- 20s: Testosterone production can peak; energy, libido, and muscle recovery can be highest
- 30s: Levels can begin a steady decline of approximately 1-2% per year; subtle changes in energy and body composition may appear
- 40s: Noticeable decline can accelerate; many women can experience the first significant symptoms of low testosterone alongside perimenopause
- 50s and beyond: Post-menopause, ovarian testosterone production can drop significantly; adrenal contribution can become the primary source
Unlike menopause - which can involve a dramatic drop in estrogen and progesterone - testosterone decline can be gradual, which can make it easier to dismiss symptoms as "normal aging."
Optimal Ranges for Women
Standard lab reference ranges for testosterone in women can be notoriously broad. A "normal" range may span from 8 to 60 ng/dL for total testosterone, which may not be clinically useful. Many functional and integrative medicine practitioners may use tighter optimal ranges:
- Total testosterone: 30-50 ng/dL (some practitioners aim higher depending on symptoms)
- Free testosterone: 3-8 pg/mL
- SHBG: 40-120 nmol/L (context-dependent)
These numbers should always be interpreted alongside symptoms. A woman with a total testosterone of 20 ng/dL who feels well may be different from one at the same level experiencing fatigue, low libido, and cognitive decline.
Lab Tests That Can Help
A thorough testosterone assessment looks at these markers together:
- Total testosterone - overall production
- Free testosterone - the biologically active fraction
- SHBG - to understand binding and bioavailability
- DHEA-S - the primary adrenal androgen precursor to testosterone
- Estradiol - testosterone-to-estrogen ratio can matter for symptom assessment
- LH and FSH - to evaluate pituitary signaling to the ovaries
- Cortisol - chronic stress can suppress androgen production
- Thyroid panel - thyroid status can directly affect SHBG and testosterone metabolism
- Fasting insulin - insulin resistance can lower SHBG and can raise free testosterone
Supporting Healthy Testosterone Levels
While testosterone replacement therapy for women is an active area of research, there may be foundational strategies that can support healthy androgen levels:
- Resistance training: Strength training can be one of the most effective natural ways to support testosterone production and sensitivity
- Adequate protein intake: Amino acids can be essential for hormone synthesis
- Quality sleep: Testosterone production can be linked to sleep quality and duration
- Stress management: Chronic cortisol elevation can suppress androgen production
- Healthy body composition: Both excess body fat and extremely low body fat can impair testosterone production
- Review medications: Oral contraceptives, certain antidepressants, and corticosteroids can all suppress testosterone or raise SHBG
References
- Davis, S. R., & Wahlin-Jacobsen, S. (2015). Testosterone in women - the clinical significance. The Lancet Diabetes & Endocrinology, 3(12), 980-992. PMID 26358173
- Zumoff, B., et al. (1995). Twenty-four-hour mean plasma testosterone concentration declines with age in normal premenopausal women. Journal of Clinical Endocrinology & Metabolism, 80(4), 1429-1430. PMID 7714119
- Wierman, M. E., et al. (2014). Androgen therapy in women: a reappraisal. Journal of Clinical Endocrinology & Metabolism, 99(10), 3489-3510. PMID 25279570
- Panzer, C., et al. (2006). Impact of oral contraceptives on sex hormone-binding globulin and androgen levels. Journal of Sexual Medicine, 3(1), 104-113. PMID 16409223
- Glaser, R., & Dimitrakakis, C. (2013). Testosterone therapy in women: myths and misconceptions. Maturitas, 74(3), 230-234. PMID 23380529
- Davison, S. L., et al. (2005). Androgen levels in adult females: changes with age, menopause, and oophorectomy. Journal of Clinical Endocrinology & Metabolism, 90(7), 3847-3853. PMID 15827095
