Free T
The biologically active testosterone available to your tissues.
What is it
Free testosterone is the small fraction of total testosterone not bound to SHBG or albumin. It is the form that directly interacts with androgen receptors in tissue.
Most clinical labs report free testosterone as a calculated value derived from total testosterone, SHBG, and albumin.
Why it's measured
Free testosterone has been associated with libido, energy, and body composition in published research and is often a more functionally meaningful number than total testosterone.
Reference range
Standard laboratory reference
Men: 9 – 30 / Women: 0.3 – 1.9 pg/mL
Reference ranges vary by laboratory. Your individual reference range will appear on your test report and should be interpreted by your physician in the context of your overall health profile.
What results may indicate
Elevated
Warrants clinical evaluation, particularly in women where it may relate to PCOS.
Lower
Has been associated with low libido, fatigue, and altered body composition in published research.
These associations are general. They are not a personal diagnosis or prediction. Discuss your individual results with your physician in the context of your full health profile.
When it's measured
Calculated when total testosterone, SHBG, and albumin are measured together.
Related markers
Measured in
A complete look at your heart, hormones, metabolism, inflammation, and longevity systems — drawn at Quest or LabCorp, reviewed by a U.S.-licensed physician.
Explore the Apex Panel →This information is for general educational purposes only and is not medical advice. Lab results alone are not intended to diagnose, treat, or cure any condition and do not replace the advice of a healthcare provider. OPTML does not offer medical advice, a diagnosis, medical treatment, or any form of medical opinion.