Biomarker education

Free testosterone: What It Measures & Why People Track It

Also called: Free T

Free testosterone measures the unbound, biologically active portion of testosterone.

General biomarker education — not personalized medical advice. Learn more

Result on your report

Illustrative

Free testosterone

Range: LowHigh

LowReference intervalHigh

What it generally measures

This test estimates or measures testosterone not bound to carrier proteins, which can differ in relative amount from total testosterone.

Common units on reports: pg/mL

Why people track it over time

Free testosterone is typically reviewed together with total testosterone rather than by itself.

Changes over time do not by themselves establish a diagnosis. Learn more

Questions you might ask a healthcare professional

Questions to bring

Illustrative
Ask how free testosterone relates to your total testosterone result.
Ask which method the lab used, since free testosterone can be measured or calculated differently between labs.

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