Free Testosterone
Free testosterone is the small fraction (1–3%) of total testosterone that is not bound to SHBG or albumin. It is the biologically active form that binds to androgen receptors.
Free testosterone provides a more accurate picture of androgen activity than total testosterone alone, especially when SHBG is abnormal.
What It Measures
Unbound, bioavailable testosterone.
Reference Ranges
| Status | Range (pg/mL) |
|---|---|
| Optimal | Men: 9–25 pg/mL. Women: 0.2–5.0 pg/mL |
| Normal | Lab-specific |
| Borderline | Below lower reference |
| Out of Range | Significantly below range |
Interpreting Your Results
When Values Are High
Low SHBG (insulin resistance, PCOS), androgen-producing conditions. More reliable than total T for detecting androgen excess.
When Values Are Low
High SHBG (OCP use), adrenal insufficiency, aging. Symptoms even with normal total T: low libido, fatigue.
How GATOR Tracks This
Lab Providers
Related Biomarkers
This content is for informational purposes only and does not constitute medical advice. Reference ranges may vary by laboratory and individual factors. Consult a qualified healthcare provider for interpretation of your results and treatment decisions.
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