Skip to content

Free Testosterone

Published: July 27, 2026Updated: August 25, 2026

Free testosterone measures the amount of testosterone that is not bound to proteins in the blood, providing insight into hormonal balance and potential reproductive issues.

Quick summary

Free testosterone indicates the unbound, biologically active form of testosterone in the blood.

Medically reviewed by WellAlly Editorial TeamLast reviewed August 25, 2026Editorial policy

Key facts at a glance

Units
pg/mL
Clinical utility
diagnostic
Result kind
quantitative
FDA-cleared
Roche Free Testosterone, Quest Free Testosterone, Salimetrics Free Testosterone
interpretation: {"text":"May indicate hypogonadism, androgen deficiency, or conditions affecting hormone production.","label":"Low Levels"}; {"text":"Could suggest hyperandrogenism, testosterone-secreting tumors, or polycystic ovary syndrome (PCOS).","label":"High Levels"}

Free testosterone is the portion of total testosterone that is not bound to proteins such as sex hormone-binding globulin (SHBG) or albumin. This unbound form is considered biologically active and plays a crucial role in various physiological processes, including the development of male secondary sexual characteristics, muscle mass, and reproductive health.

The measurement of free testosterone is particularly useful in diagnosing conditions such as hypogonadism, infertility, and polycystic ovary syndrome (PCOS). It helps clinicians assess hormonal imbalances that may affect sexual function, mood, and overall well-being.

Normal reference ranges for free testosterone are typically between 47–244 pg/mL. Deviations from this range may indicate conditions such as hyperandrogenism or hypogonadism, necessitating further evaluation and management.

Frequently asked questions

What is the difference between total and free testosterone?
Total testosterone includes both bound and unbound testosterone, while free testosterone only measures the unbound, biologically active form.
How is free testosterone measured?
Free testosterone is typically measured through blood tests using techniques such as equilibrium dialysis or calculated from total testosterone, SHBG, and albumin levels.
  1. 1
    Free Testosterone - Lab Tests OnlineSource
  2. 2
    Testosterone, Free and Total - Mayo ClinicSource

Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.

This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.

Medical Disclaimer

This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.

If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.

Medically reviewed by WellAlly Editorial Team Last reviewed August 25, 2026. · Read our editorial policy