---
title: "Total vs free testosterone: what each measures and which one to rely on"
type: biomarker-comparison
url: "https://www.test-well.com/biomarkers/compare/total-vs-free-testosterone"
biomarkers:
  - Total Testosterone
  - Free Testosterone
reviewed_at: 2026-11-04
review_status: reviewed
date_published: 2026-11-04
---

# Total vs free testosterone: what each measures and which one to rely on

> Total testosterone measures everything in the blood — the 40–50% bound tightly to sex hormone–binding globulin (SHBG), the roughly 50% bound loosely to albumin, and the 2–3% that is free. Free testosterone is that last fraction, the part that can enter cells. Guidelines diagnose low testosterone on two fasting morning total values because the total is the accurate, standardized measurement; free testosterone is added when the total is borderline or when SHBG is likely to be abnormal, because a high SHBG can make a man with a normal total functionally low and a low SHBG can make a low total misleading. How the free value is produced matters: calculated or equilibrium-dialysis values are reliable, the direct 'analog' immunoassay is not.


## Total Testosterone vs Free Testosterone side by side

|  | Total Testosterone | Free Testosterone |
| --- | --- | --- |
| What it measures | All circulating testosterone: SHBG-bound, albumin-bound and free | The unbound 2–3% that can enter cells; 'bioavailable' testosterone adds the loosely albumin-bound share |
| Normal range (adults) | Male, age 18+: 264 – 916 ng/dL; Female, age 18+: 15 – 70 ng/dL | Male, age 18+: 47 – 244 pg/mL; Female, age 18+: 0.1 – 6.4 pg/mL |
| How it is measured | Immunoassay (adequate in men) or LC-MS/MS (needed for women and children, where levels are low) | Best by equilibrium dialysis or calculated from total, SHBG and albumin (Vermeulen); the direct analog immunoassay is inaccurate |
| Guideline role | The diagnostic test — two fasting morning values below the threshold (AUA 300 ng/dL; Endocrine Society 264) | The tiebreaker when the total is borderline (roughly 200–400 ng/dL) or SHBG is abnormal |
| Misleadingly low when | SHBG is low — obesity, insulin resistance, type 2 diabetes, hypothyroidism, nephrotic syndrome, androgen or glucocorticoid use | The analog assay was used; a dose of testosterone gel contaminated the skin at the draw site |
| Misleadingly normal when | SHBG is high — ageing, hyperthyroidism, liver disease, HIV, estrogen, anticonvulsants, low body weight | Rarely; a calculated value depends on an accurate SHBG and albumin |
| Timing | 7–10 AM, fasting, on two separate days; not during illness | Same draw as the total, with SHBG |


## What SHBG does to the numbers

Sex hormone–binding globulin holds testosterone so tightly that the bound share is unavailable to cells. When SHBG is high — with age, hyperthyroidism, liver disease, HIV, estrogen, some anticonvulsants, or simply a lean build — more of the total is locked up: the total can read 400 ng/dL while the free is below range, and the man has symptoms of low testosterone. When SHBG is low — obesity, insulin resistance, type 2 diabetes, hypothyroidism, nephrotic syndrome, androgen or steroid use — less is bound, and a total of 250 can go with a normal free value and no deficiency. This is why the Endocrine Society and AUA guidelines ask for a free (or bioavailable) testosterone whenever the total is near the threshold or an SHBG-altering condition is present.

## Why total is the first test, and when free settles it

Total testosterone is the better-standardized measurement — immunoassays are calibrated against mass spectrometry through the CDC's standardization program, and the diagnostic thresholds (300 ng/dL in the AUA guideline, 264 in the Endocrine Society's harmonized range) were set on totals. So the sequence is: two fasting morning totals on separate days; if both are clearly low or clearly normal, the question is answered; if either is borderline, or SHBG is likely abnormal, add SHBG and a calculated or dialysis free testosterone, and read that against its own reference range (roughly above 47–65 pg/mL depending on the method).

The repeat is not a formality: 30% of men with one low morning value are normal on the second, and a value drawn in the afternoon, after a poor night's sleep, during an illness or after a large meal runs low in everyone.

## How free testosterone should be measured

Three methods appear on lab reports. Equilibrium dialysis physically separates the free hormone and is the reference method. The calculated free testosterone (Vermeulen or Sodergard formula) uses the total, SHBG and albumin and agrees well with dialysis; most large laboratories report it. The direct 'analog' free testosterone immunoassay, still offered by some labs, under-reads badly and tracks SHBG rather than the true free fraction — the Endocrine Society advises against relying on it. If your report does not say which method was used, assume the least reliable one and ask.

## In women

Women's testosterone levels are a tenth of men's, below the accurate range of most total-testosterone immunoassays, so for PCOS, hirsutism and suspected androgen excess the total should be measured by LC-MS/MS and the free testosterone or free androgen index (total ÷ SHBG × 100) calculated. A low SHBG, common in PCOS and insulin resistance, is often the reason a woman with a normal total has androgen symptoms.

## How do you test Total Testosterone and Free Testosterone?

| Test or panel | Type | Price | Fasting | Results |
| --- | --- | --- | --- | --- |
| [Erectile Dysfunction Panel](https://www.test-well.com/tests/erectile-dysfunction-panel) | Panel (7 tests) | $114.99 | Yes | 2–5 business days |
| [Men's Hormone Panel](https://www.test-well.com/tests/mens-hormone-panel) | Panel (7 tests) | $199.99 | No | 3–5 business days |
| [Men's Health Panel](https://www.test-well.com/tests/mens-health-panel) | Panel (8 tests) | $139.99 | Yes | 2–5 business days |
| [Free & Total Testosterone Test](https://www.test-well.com/tests/testosterone-free-and-total) | Test | $45.99 | No | 3–5 business days |
| [Free & Total Testosterone + SHBG Test](https://www.test-well.com/tests/testosterone-free-total-shbg) | Test | $69.99 | No | 3–5 business days |

Plus one $6 lab processing fee per order; physician authorization included.

## Common questions

### Can total testosterone be normal but free testosterone low?

Yes — when SHBG is high, which happens with age, hyperthyroidism, liver disease, HIV, estrogen exposure, some anticonvulsants and a lean build. More of the testosterone is bound and unavailable, so a man can have a total of 350–450 ng/dL, a free value below range and genuine symptoms. That is the situation the guidelines have in mind when they ask for a free testosterone.

### Which is more accurate, total or free testosterone?

Total, as a measurement — it is standardized and the diagnostic thresholds were set on it. Free testosterone is more physiologically meaningful but only as reliable as the method: calculated or equilibrium-dialysis values are trustworthy, the direct analog immunoassay is not. The guidelines use the total first and a properly measured free value to resolve borderline or SHBG-altered cases.

### What is a normal free testosterone level?

Reference ranges depend on the method: roughly 47–244 pg/mL for the calculated or dialysis free testosterone in adult men in many laboratories, with the lower limit around 50–65 pg/mL by Endocrine Society harmonized data. A result from a direct analog assay cannot be compared with these. Read the free value against the range printed for that specific method.

### Do I need SHBG with my testosterone test?

Not for a first screen if the total is clearly normal or clearly low. SHBG becomes necessary when the total is borderline, when you have a condition that moves SHBG (obesity, diabetes, thyroid or liver disease, HIV, estrogen or anticonvulsant use, older age), or whenever a calculated free testosterone is wanted — the calculation requires it.

## Related

- [Total Testosterone: reference range and what high or low means](https://www.test-well.com/biomarkers/total-testosterone)
- [Free Testosterone: reference range and what high or low means](https://www.test-well.com/biomarkers/free-testosterone)
- [FSH vs LH: what's the difference?](https://www.test-well.com/biomarkers/compare/fsh-vs-lh)
- [Lab results explainer](https://www.test-well.com/tools/lab-results-explainer)

## Sources

- [Endocrine Society Clinical Practice Guideline: Testosterone Therapy in Men With Hypogonadism (2018)](https://academic.oup.com/jcem/article/103/5/1715/4939465)
- [American Urological Association, Evaluation and Management of Testosterone Deficiency (2018)](https://www.auanet.org/guidelines-and-quality/guidelines/testosterone-deficiency-guideline)
- [Vermeulen, Verdonck & Kaufman, A critical evaluation of simple methods for the estimation of free testosterone in serum (J Clin Endocrinol Metab 1999)](https://academic.oup.com/jcem/article/84/10/3666/2660412)
- [Endocrine Society](https://www.endocrine.org/clinical-practice-guidelines/testosterone-therapy)
- [Endocrine Society — Testosterone Therapy in Men With Hypogonadism (2018)](https://doi.org/10.1210/jc.2018-00229)
- [MedlinePlus (NIH) — Testosterone Levels Test](https://medlineplus.gov/lab-tests/testosterone-levels-test/)

---

Medically reviewed by Youmna DiStefano, MD (Medical Reviewer, TestWell); last reviewed 2026-11-04. Review policy: https://www.test-well.com/reviewers/youmna-distefano-md

Canonical page: https://www.test-well.com/biomarkers/compare/total-vs-free-testosterone
Machine-readable catalog: https://www.test-well.com/api/catalog.json · MCP server: https://www.test-well.com/mcp · Overview for agents: https://www.test-well.com/llms.txt

Prices are cash-pay, in USD, and include physician authorization; every order adds one flat $6 lab processing fee. Educational content is not a diagnosis — discuss results with a clinician.