Free testosterone optimal range and reference range

Compiled by Alina Radu, founder of Sera, from the published sources below · Last reviewed November 9, 2026

Sera's bands for Free testosterone, which differ for men and women:

Female: Optimal 1.5 – 4 pg/mL (5.2 – 13.9 pmol/L); sufficient 0.5 – 4.5 pg/mL (1.7 – 15.6 pmol/L); out of range below 0.5 or above 4.5 pg/mL.
Male: Optimal 15 – 25 pg/mL (52 – 87 pmol/L); sufficient 4.8 – 30 pg/mL (16.7 – 104 pmol/L); out of range below 4.8 or above 30 pg/mL.

Evidence grade: Functional / longevity target. A narrower target in common use in functional, integrative, preventive and longevity practice. It is not a universally validated diagnostic range.

All units

Unit	Applies to	Optimal	Sufficient	Out of range
pg/mL	Female	1.5 – 4	0.5 – 4.5	below 0.5 or above 4.5
pg/mL	Male	15 – 25	4.8 – 30	below 4.8 or above 30
pmol/L	Female	5.2 – 13.9	1.7 – 15.6	below 1.7 or above 15.6
pmol/L	Male	52 – 87	16.7 – 104	below 16.7 or above 104
ng/dL	Female	0.15 – 0.4	0.05 – 0.45	below 0.05 or above 0.45
ng/dL	Male	1.5 – 2.5	0.48 – 3	below 0.48 or above 3
nmol/L	Male	0.4 – 0.65	0.22 – 0.73	below 0.22 or above 0.73
nmol/L	Female	0.015 – 0.036	0.008 – 0.047	below 0.008 or above 0.047

What the evidence says

Free testosterone is reported on two scales that differ about tenfold, and the unit tells them apart. Results in pg/mL, pmol/L and ng/dL are read as a direct immunoassay; results in nmol/L are read as calculated free testosterone, worked out from total testosterone, SHBG and albumin. Equilibrium dialysis, which some laboratories report in ng/dL or pg/mL, runs several times higher than a direct assay and should be read against the report's own range. For men, the nmol/L lower edge of 0.22 is the European urology threshold for a low calculated free testosterone. The other edges, and all the optimal bands, are functional targets without a published source: Labcorp's direct-assay interval for men aged 20 to 29 is 9.3 to 26.5 pg/mL, narrower than the band here, and intervals fall with age. Direct assays are unreliable at female concentrations.

For women: These ranges are informative, not diagnostic, and reflect women in their reproductive years (pre-menopausal). Free testosterone tracks total testosterone and varies across the menstrual cycle (peaking around ovulation), so the ranges are intentionally wide. It is also affected by SHBG and declines with age.

Menstrual cycle: Female range spans the cycle, tracking total testosterone.

Assay: Results differ meaningfully between platforms and methods. Compare against the interval printed by the issuing laboratory before acting on a borderline value.

Sources

Testosterone, Total, Bioavailable, and Free, Serum (TTFB) — Mayo Clinic Laboratories, 2026 · Laboratory / reference-interval sourceFree testosterone by equilibrium dialysis: men 5.25 to 20.7 ng/dL at 20 to 25 years, falling to 3.67 to 13.9 at 60 to 65; women below 0.13 to 1.08 ng/dL at 20 to 25 years. Sera's male ng/dL band of 0.48 to 3 lies wholly below this interval.
Testosterone, Free, Direct (test 144980) — Labcorp, 2026 · Laboratory / reference-interval sourceDirect analog immunoassay: men 9.3 to 26.5 pg/mL at 20 to 29 years, falling to 6.6 to 18.1 over 59; women over 19, 0.0 to 4.2 pg/mL. This is the scale Sera's pg/mL rows are on, but no edge matches and women have no lower limit.
EAU Guidelines on Sexual and Reproductive Health: Male Hypogonadism — European Association of Urology, 2026 · Clinical guidelineA calculated free testosterone of 220 pmol/L (6.4 ng/dL) can be used as a threshold for hypogonadism where SHBG may be altered, on limited evidence. This equals Sera's male nmol/L lower edge of 0.22, and is about thirteen times Sera's pmol/L lower edge of 16.7.
Global Consensus Position Statement on the Use of Testosterone Therapy for Women — Davis SR, Baber R, Panay N, et al. — The Journal of Clinical Endocrinology & Metabolism, 2019 · Professional societyDirect assays for free testosterone are highly unreliable at female concentrations, so no female band can be defended for a direct-assay result.

What Testosterone (Free) measures

The free, active testosterone that is not bound to proteins.

Free testosterone is the part the body can actually use. Low levels can add to fatigue and low sex drive.

Related hormone health markers

See Free testosterone in the full list of biomarker ranges

This page is a reference for practitioners, not medical advice. Sera's bands are practitioner targets for structured review, not diagnostic thresholds, and Sera does not diagnose or recommend treatment. Read a result alongside the interval printed by the issuing laboratory and the client's history and symptoms. Range set: Sera Production, version 1.0, last reviewed November 9, 2026.