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Glossary term
Free testosterone
Also known as Bioavailable testosterone fraction
The 1-2% of testosterone that isn't bound to SHBG. The number that actually predicts symptoms.
Free testosterone is the small fraction of circulating testosterone not bound to SHBG or albumin, making it available to bind androgen receptors. In men, reference ranges run roughly 6.8-21.5 ng/dL depending on assay; under 6-9 ng/dL on a morning LC-MS draw predicts hypogonadal symptoms far better than total testosterone alone. High SHBG masks low free T behind a normal total - a common miss in men over 50. Always order with SHBG and total testosterone on an early-morning fasted draw. See the testosterone-panel guide before acting on a single number.
- Symbol
- Free T
- Unit
- ng/dL
- Typical range
- Adult men roughly 6.8-21.5 ng/dL (assay-dependent).
Medically reviewed byDr. Lena Okafor, MD
Medical Director - updated April 2026How we review
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