What are normal testosterone levels in females?

Normal Testosterone Levels in Females

Normal total testosterone levels in healthy adult females range from approximately 15-46 ng/dL (520-1595 pmol/L), with free testosterone ranging from 1.2-6.4 pg/mL (4.16-22.2 pmol/L). 1

Reference Ranges by Age and Reproductive Status

Premenopausal Women (18-49 years)

• Total testosterone: 15-46 ng/dL (5th to 95th percentile for a typical 30-year-old woman) 1
• Free testosterone: 1.2-6.4 pg/mL 1
• Bioavailable testosterone: 1.12-7.62 ng/dL 1
• Testosterone levels exhibit an age-related decline throughout the reproductive years, while SHBG remains relatively stable 1

General Female Population

• A study of women without clinical signs of hyperandrogenism found mean testosterone levels of 14.1 ng/dL (95% CI: 12.4-15.8 ng/dL) 2
• The upper limit of normal (mean + 2 standard deviations) was 28 ng/dL in this reference population 2
• Normal healthy females demonstrate testosterone levels of 0.4-2.0 nmol/L (approximately 11.5-57.6 ng/dL), which is four- to fivefold lower than the lower end of the male range 3

Critical Measurement Considerations

Timing and Methodology

• Testosterone levels can be measured at any point in the menstrual cycle, as the mid-cycle increase is relatively small compared to overall variability 1
• Morning blood samples are preferred for consistency, though this is less critical in females than males 1
• Validated immunoassays or LC-MS/MS methods should be used, as standard immunoassays often lack accuracy below 100 ng/dL 4

Laboratory Variability Warning

• Commercial laboratory reference ranges are often inappropriately wide (sometimes up to 95 ng/dL as the upper limit), making detection of hyperandrogenemia nearly impossible 2
• There is wide variability between laboratories, with low reference values ranging from 130-450 ng/dL across different labs (though these appear to be male-focused ranges) 5
• The reference ranges established in research studies (15-46 ng/dL) are far more clinically useful than commercial laboratory ranges 2

Clinical Context for Postmenopausal Women

Important Guideline Limitations

• There are no validated reference ranges for "optimal" testosterone in postmenopausal women, making interpretation of measured values clinically meaningless 6
• The American College of Physicians recommends against routine testosterone measurement in women outside of research contexts 6
• No proven benefits exist for testosterone replacement therapy in postmenopausal women 6

Diagnostic Approach

• If a postmenopausal woman presents with symptoms potentially attributable to androgen deficiency, the workup should focus on excluding other causes rather than measuring testosterone levels 6
• Evaluate for thyroid dysfunction, depression, medication effects, and other hormonal abnormalities first 6

Pathological Elevations

• Women with menstrual dysfunction but no hirsutism show mean testosterone of 17.9 ng/dL 2
• Mild hirsutism is associated with levels of 38.4 ng/dL 2
• Moderate to severe hirsutism correlates with levels of 49.0 ng/dL 2
• Women with PCOS or congenital adrenal hyperplasia have levels above the normal female range but still below the normal male range 3

Key Clinical Pitfalls

• Using commercial laboratory reference ranges will miss most cases of hyperandrogenemia in women, as these ranges are often established without adequate clinical validation 2
• A sensitivity of 84% for detecting hyperandrogenemia is achieved using 28 ng/dL as the upper limit, not the 95 ng/dL often provided by commercial labs 2
• The bimodal distribution between males and females is clear, with minimal overlap between normal ranges 3