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Testosterone
Free Testosterone
The portion of testosterone not bound to proteins, available for your body to use.
What It Measures
Testosterone that is unbound and biologically active in your bloodstream.
Reference Range
5 pg/mLOptimal: 15–25 pg/mL25 pg/mL
Optimal free testosterone is typically 15-25 pg/mL for adult men.
If High
May indicate excess testosterone production or supplementation.
If Low
Even with normal total T, low free T means your body can't use enough testosterone.