Biomarker hub·hormones
Hormones · Bioavailable fraction

Free Testosterone(FT)

Free testosterone is the unbound, biologically-active fraction of total T — what actually crosses cell membranes and activates androgen receptors.

Optimal range
150–250pg/mL
Clinical "normal"
50–210 pg/mL
Avg. cost (US)
$95
Test frequency
With total T, every 3–6 months
When to measure
Same draw as total T, fasted, 7–9 AM. Calculated values (from total T + SHBG + albumin) are usually preferred over direct assays.
How to measure
Calculated from total T + SHBG (Vermeulen formula) is gold standard. Direct assays exist but vary in accuracy.
Average cost
≈ $95 cash price. Often covered by insurance with relevant ICD-10.

Signs your level is off

Symptoms if low

Erectile dysfunction, mood swings.

Symptoms if high

Similar to TT high.

If your level is low

Boron >10 mg: hormonal imbalance

Supplement
Boron· 6-10 mg/day
Form: Boron glycinate
Reduces SHBG binding.
Foods
  • Fatty fish
Lifestyle
  • Intermittent fasting
Medication (if prescribed)
hCG· 500 IU 3x/week
Form: Injectable
Reference only. Speak with a licensed clinician before any prescription intervention.
Caution: Boron >10 mg: hormonal imbalance

If your level is high

GI upset

Supplement
Calcium D-Glucarate· 500 mg/day
Form: Capsule
Enhances estrogen excretion.
Foods
  • Flaxseeds
Lifestyle
  • Limit endurance cardio
Medication (if prescribed)
Anastrozole· 0.25 mg/day
Form: Oral
Reference only. Speak with a licensed clinician before any prescription intervention.
Caution: GI upset

Test these together

These biomarkers contextualize Free Testosterone and unlock a clearer picture than any single value can.

Deeper reading

Protocols that move this marker

Selected studies

EMAS 2025 PubMed

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