Testosterone, Bioavailable

This test measures the fraction of testosterone that’s not bound up tightly by SHBG (sex hormone binding globulin). It’s the “usable” testosterone that can actually interact with your tissues—muscle, brain, libido, recovery. For athletes and biohackers, this is often more telling than just “total T.”

Immunoassay or LC/MS? How testosterone tests differ, and why the 1,500 cap matters

Unit

ng/dL

Health impacts

Mood · Recovery · Metabolic Health · Libido · Brain Fog