What is Free / bioactive testosterone?
the active part of your testosterone
Bioactive testosterone is the free and loosely bound fraction - the part that actually affects body tissues.
The value matters when investigating low testosterone because total testosterone can be normal even when bioactive testosterone is low, especially when SHBG is raised.
Test facts
- Unit
- pmol/L
- Sample
- Serum
- Fasting
- No fasting needed
- Turnaround
- 3 days
What does low Free / bioactive testosterone mean?
Low bioactive testosterone suggests functional androgen deficiency and can cause symptoms even when total testosterone looks normal.
What does high Free / bioactive testosterone mean?
High values are read in the context of total testosterone and SHBG.
Panels that measure Free / bioactive testosterone
- Male Annual
- Testosterone Check
- Hormone+
- Longevity Full
- Athlete Performance
More markers in the same area
Launching in Stockholm in 2026.
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This is general information about the marker, not an assessment of your values and not medical advice. Last updated: May 2026.