Normal Testosterone Levels in Adult Women
The normal total serum testosterone range for adult women is approximately 15-46 ng/dL (0.52-1.60 nmol/L), with free testosterone ranging from 1.2-6.4 pg/mL (4.16-22.2 pmol/L). 1
Reference Ranges by Measurement Type
Total Testosterone
- The 5th to 95th percentile range for a typical 30-year-old woman is 15-46 ng/dL (520-1595 pmol/L), established using validated immunoassays in 161 healthy, normally cycling premenopausal women 1
- Some studies report slightly lower ranges, with mean values around 14.1 ng/dL in women without acne, hirsutism, or menstrual dysfunction 2
- The upper limit of normal should be approximately 28 ng/dL (mean + 2 standard deviations), which provides 84% sensitivity for detecting hyperandrogenemia 2
Free Testosterone
- Normal free testosterone ranges from 1.2-6.4 pg/mL (4.16-22.2 pmol/L) by direct measurement 1
- Calculated free testosterone ranges from 1.3-5.6 pg/mL (4.5-19.4 pmol/L) 1
- Free testosterone measurement by equilibrium dialysis is the gold standard method, as it represents the metabolically active fraction 3
Bioavailable Testosterone
- Normal bioavailable testosterone (free plus albumin-bound) ranges from 1.12-7.62 ng/dL (38.8-264.21 pmol/L) 1
Sex Hormone-Binding Globulin (SHBG)
- Normal SHBG levels in premenopausal women range from 18-86 nmol/L 1
- SHBG remains relatively stable across age ranges in premenopausal women, unlike testosterone which shows age-related decline 1
Critical Context: Sex Differences
Women have testosterone levels that are 15-25 times lower than men, with a clear bimodal distribution between sexes 3, 4
- Healthy adult males: 8.8-30.9 nmol/L (approximately 254-891 ng/dL) 4
- Healthy adult females: 0.4-2.0 nmol/L (approximately 11.5-58 ng/dL) 4
- The lower end of the male range is four- to fivefold higher than the upper end of the female range 4
Age-Related Changes
- Serum testosterone concentrations exhibit age-related decline in premenopausal women 1
- SHBG levels remain relatively stable across the reproductive years 1
Menstrual Cycle Variation
- Testosterone shows a small mid-cycle increase, but this variation is relatively minor compared to overall variability 1
- Reference ranges can be applied irrespective of menstrual cycle day when the sample is taken 1
- Blood samples should ideally be collected in the morning for consistency 1
Clinical Thresholds for Hyperandrogenemia
Menstrual Dysfunction Without Hirsutism
- Mean testosterone rises to 17.9 ng/dL (95% CI: 15.7-20.0 ng/dL) 2
Mild Hirsutism
- Mean testosterone increases to 38.4 ng/dL (95% CI: 27.4-49.4 ng/dL) 2
Moderate to Severe Hirsutism
- Mean testosterone reaches 49.0 ng/dL (95% CI: 44.4-53.6 ng/dL) 2
PCOS and Congenital Adrenal Hyperplasia
- Women with these conditions have testosterone levels above the normal female range but still below the normal male range 4
Critical Laboratory Considerations
Commercial laboratory reference ranges are often inappropriately wide and fail to detect hyperandrogenemia in most affected women. 2
- Many commercial labs report upper limits as high as 95 ng/dL, making detection of hyperandrogenemia essentially impossible 2
- There is wide variability in laboratory reference values, with low reference values ranging from 130-450 ng/dL in some labs (though these appear to be male ranges reported in error) 5
- Only four centers apply age-adjusted reference values for total testosterone 5
- Reference values are typically established using statistical models without clinical considerations for symptoms of androgen excess or deficiency 5
Measurement Method Recommendations
Free testosterone should be measured by equilibrium dialysis or calculated using validated formulas (Vermeulen method) rather than direct immunoassays, which are unreliable. 3