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.

Calculated free testosterone (from total T + SHBG + albumin via Vermeulen equation) is preferred over direct immunoassay. Free androgen index (FAI = total T x 100 / SHBG) is widely used; FAI > 4-5 suggests hyperandrogenism in PCOS.

Optimal range (women)

reproductive · perimenopause · postmenopause

0.5–1.9pg/mL

Cycle: Cycle day 2-5 if assessing for PCOS or hyperandrogenism.

Clinical "normal"

0.3–1.9 pg/mL

Avg. cost (US)

$95

Test frequency

With total T, every 3–6 months

When to measure

Cycle day 2-5 for cycling women if hyperandrogenism workup; morning draw. Calculate from total T + SHBG (Vermeulen) — avoid direct analog immunoassays.

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

Reduced libido and arousal, fatigue, low motivation, blunted response to resistance training, persistent low mood despite estrogen replacement.

Symptoms if high

Hirsutism, acne, androgenic alopecia, irregular cycles — most sensitive marker of bioavailable androgen excess in PCOS (total T often normal while free T elevated due to low SHBG).

If your level is low

Boron >10 mg: hormonal imbalance

Supplement

DHEA (low-dose, selected cases)· 10-25 mg/day, physician-supervised

Form: micronized oral

Modest peripheral conversion to T and E2

Foods

adequate protein
zinc
healthy fats

Lifestyle

heavy resistance training
sleep 7-9h
reduce chronic stress

Medication (if prescribed)

Transdermal testosterone (off-label HSDD only)· ~5 mg/day; target free T in upper-normal female range

Form: compounded cream

Reference only. Speak with a licensed clinician before any prescription intervention.

Caution: Free T alone does not justify androgen therapy outside HSDD. Avoid supraphysiologic dosing.

If your level is high

GI upset

Supplement

Inositol (myo+D-chiro 40:1)· 4 g myo + 100 mg D-chiro daily

Form: powder

Improves insulin sensitivity; raises SHBG and lowers free T

Foods

low-glycemic Mediterranean diet
fiber > 25 g/day
limit alcohol (lowers SHBG)

Lifestyle

weight loss if BMI > 25
resistance training
stress reduction

Medication (if prescribed)

Spironolactone or combined OC· Spironolactone 50-200 mg/day

Form: Oral

Reference only. Speak with a licensed clinician before any prescription intervention.

Caution: Spironolactone is teratogenic — contraception required. Investigate adrenal/ovarian tumor if free T grossly elevated with rapid-onset virilization.