Free Testosterone: what is a good level?

Written by Steve Fayzulayev. Clinically reviewed by Naomi Fayzulayev, FNP-C, MSN.

Last reviewed 2026-11-09. See our editorial policy and methodology.

Reference intervals depend on the laboratory, assay method and population. Use the interval on your report and discuss the result with your clinician; its compatibility with the calculator's scoring ranges has not been verified.

Longevity-optimised target Men: 15–30 pg/mL. Women: 1–4 pg/mL. The calculator scores values above or below these ranges differently.

This is the range used by the hormonal dial in the Longevity Score calculator. It is deliberately tighter than the range printed on a standard lab report — the reasoning is below.

Men's calculator scoring examplepg/mL
Standard
not shown
Optimised
Men: 15–30 pg/mL. Women: 1–4 pg/mL. The calculator scores values above or below these ranges differently.
017.535

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No reference interval is shown because results and intervals depend on the assay and laboratory. The brighter band shows the calculator's scoring range for men only; scoring for women differs. Assay compatibility has not been verified. This is not a diagnosis or treatment target.

What Free Testosterone actually measures

Free testosterone is the small unbound fraction of circulating testosterone. The rest is bound to proteins including sex hormone-binding globulin (SHBG) and albumin.

Total testosterone includes bound and unbound hormone. SHBG can affect how total and free testosterone results relate, but neither result alone establishes how much hormone a particular tissue uses.

Why it matters

SHBG varies with age, health conditions and medications. A clinician may consider free testosterone when total testosterone is borderline or SHBG is altered.

Symptoms such as low energy or reduced libido have many possible causes. A clinician can decide whether additional testosterone testing is useful alongside the clinical history and total testosterone result.

In women, androgen results also require assay-specific interpretation and clinical context; a calculator band does not diagnose a deficiency or excess.

Why it's on the dashboard

The calculator includes free testosterone separately from total testosterone. Some free testosterone results are calculated using total testosterone and SHBG, while others are measured using different methods. Their compatibility with the calculator's scoring ranges has not been verified. A clinician can determine whether testing is appropriate and interpret the result in context. See the Hormonal dial for the broader context.

Why this range is stricter than your lab's

Laboratory reference intervals depend on the assay and reference population. They are separate from the calculator's book-based scoring range and may vary between laboratories.

The calculator scores 15–30 pg/mL as its optimal range for men. This book-based scoring range is not a clinical treatment target, and its compatibility with different assay methods needs clinical review.

For women the calculator uses a scoring window. An elevated result has several possible causes, including polycystic ovary syndrome, and needs clinical interpretation.

This distinction applies across the whole panel, not just this marker — see optimal versus standard lab ranges for the general case.

What moves Free Testosterone

Health and medications
Sleep, illness, medicines and conditions affecting SHBG can influence interpretation.
Testosterone therapy
Treatment is a clinical decision with fertility, haematocrit and other considerations. Never start or change it based on a calculator score.

Educational information, not a treatment plan. Discuss changes to medication or supplementation with a clinician who knows your history.

How fast it responds

Levels vary during the day and between measurements. Ask your clinician whether and when repeat testing is appropriate. See response times across all markers for how this compares.

What can distort the result

Score Free Testosterone against all 8 dials

Frequently asked questions

What is a good Free Testosterone level?

The longevity-optimised target used in this calculator is Men: 15–30 pg/mL. Women: 1–4 pg/mL. The calculator scores values above or below these ranges differently.. Reference intervals depend on the laboratory, assay method and population. Use the interval on your report and discuss the result with your clinician; its compatibility with the calculator's scoring ranges has not been verified.

Why is this target stricter than the range on my lab report?

Laboratory reference intervals depend on the assay and reference population. They are separate from the calculator's book-based scoring range and may vary between laboratories.

How fast does Free Testosterone respond to change?

Levels vary during the day and between measurements. Ask your clinician whether and when repeat testing is appropriate.

Free Testosterone feeds the hormonal dial, and read it alongside Testosterone · TSH · Estradiol.

All biomarkers

Sources and further reading

These sources provide general context; calculator scoring ranges are not clinical treatment targets.

Not medical advice. These are longevity-optimised reference ranges, which are deliberately stricter than standard clinical "normal" values. A value outside them does not mean you have a disease. Speak to a qualified healthcare professional before changing medication, supplements or training. Full disclaimer.
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What is a good Free Testosterone level?

The longevity-optimised target used in this calculator is Men: 15–30 pg/mL. Women: 1–4 pg/mL. The calculator scores values above or below these ranges differently.. Reference intervals depend on the laboratory, assay method and population. Use the interval on your report and discuss the result with your clinician; its compatibility with the calculator's scoring ranges has not been verified.

Why is this target stricter than the range on my lab report?

Laboratory reference intervals depend on the assay and reference population. They are separate from the calculator's book-based scoring range and may vary between laboratories.

How fast does Free Testosterone respond to change?

Levels vary during the day and between measurements. Ask your clinician whether and when repeat testing is appropriate.

What is biological age?

Chronological age counts birthdays. Biological age estimates how old your body appears to be functioning, based on measurable biomarkers. Two people born the same year can differ by a decade or more in vascular stiffness, insulin signalling or cardiorespiratory fitness. Biological age makes that gap explicit — and unlike your birthday, it can move in either direction.

How is the Longevity Score calculated?

Each biomarker you enter is scored against longevity-optimised reference ranges and grouped into one of eight dials. Every dial produces its own biological age, and those are combined using fixed weights into a single composite, then expressed as a Longevity Score from 0 to 100. The weighting reflects how strongly each system predicts healthspan: structural and vascular carry the most, hormonal the least.

Do I need all 53 biomarkers?

No. The short form contains a subset of scoring inputs plus context-only fields, and you can leave any of them blank. It is not a recommendation to obtain tests. Missing values are excluded from the calculation — never treated as zero or as 'normal'. A dial with no scored data is dropped entirely and the remaining weights renormalise.

What can I measure without a blood test?

Some inputs can be measured without bloodwork. Blood pressure needs a home cuff and waist-to-height needs a tape measure. Wearable estimates vary; the floor-based sitting-rising test carries a fall risk and should only be attempted if safe.

Is this an anti-aging calculator? Is it a healthspan calculator?

Both terms describe what this tool does, and which one fits depends on what you are asking. "Anti-aging" is the term most people search, and loosely means anything aimed at slowing or reversing age-related decline — this tool fits that description if you score your dials and act on what you find. "Healthspan calculator" is the more precise term: healthspan is the number of years lived without serious chronic disease or disability, and that cannot be measured directly, so this tool scores eight systems that each function as an early-warning proxy for it. Either way, the method is the same: real biomarkers, published thresholds, no vanity-metric framing.

Why don't you have a quick quiz that skips biomarkers entirely?

Several popular tools ask only about habits — exercise days, sleep hours, smoking, diet quality — and return a single precise-looking age. We looked at the research behind that approach and chose not to build it. Published studies do show real, individually-measured links between specific habits and epigenetic age acceleration, but those effect sizes come from different study populations, different DNA-methylation clocks and different measurement units. Adding them together into one number is not something the underlying research actually supports — it produces a precise-looking result built on an imprecise method. Our dials use direct physiological measurements instead: a real blood pressure reading, a real VO₂ max, a real ApoB value. Several dials score from home-measurable data alone with no quiz-guessing involved — see what you can measure without a blood test, above.

Why are your 'optimal' ranges stricter than my lab's normal range?

Standard reference ranges describe what is common in a general population, which now includes a great deal of metabolic dysfunction. They are tuned to flag disease, not to identify what is optimal for a long healthspan. A fasting insulin of 20 µIU/mL sits inside most labs' normal range and is strongly associated with insulin resistance. This tool uses longevity-optimised thresholds instead, so a flag here means room for optimisation — not a diagnosis.

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