Testosterone, Free

Advanced wellness

also free t

What it isThe fraction of testosterone not bound to transport proteins — the portion freely available to enter cells and bind androgen receptors.

DoesProvides the functionally active testosterone reaching tissues; SHBG variations make total testosterone a poor proxy in some men.

GoodMid-high free testosterone signals robust androgen signaling at the tissue level and tracks muscle mass, libido, energy, and metabolic health.

BadLow free testosterone — even with normal total testosterone — drives all hypogonadal symptoms. Common in older men with high SHBG.

Standard

8.7–25.1 pg/mL (age <50).

Optimal

20–28 pg/mL (narrow target)

Modifiers

SHBG dominates; rises with weight loss and resistance training; falls with obesity, alcohol, opioids, poor sleep.

How to optimize

Lifestyle: Resistance training, sleep, weight loss, limit alcohol.
Diet: Adequate calories, protein, healthy fats; zinc, magnesium, vitamin D.
Supplements: Zinc (15–30mg/day), magnesium glycinate (300–400mg/day), vitamin D3 (target 60–80 ng/mL), boron (5–10mg/day), ashwagandha, tongkat ali.
Peptides: Kisspeptin-10, gonadorelin.
Drugs: Testosterone replacement, hCG, clomiphene, enclomiphene.

within Men's Hormones