UF Health lists male free testosterone ranges of 9.3 to 26.5 pg/mL at ages 20 to 29 and 6.6 to 18.1 pg/mL after age 59 on its direct analog assay.1 Every lab we order gets read by a physician before anyone is offered a treatment. Normal free testosterone depends on your age, the measurement method, the unit, and your laboratory, and results from different methods cannot be compared directly.2
Free Testosterone Ranges by Age
A normal free testosterone level for your age is the age-specific interval reported by the laboratory that tested your sample.
The following free testosterone chart comes from UF Health Pathology Laboratories. It applies to male results from a direct analog enzyme immunoassay and uses pg/mL.1
| Age | Male Free Testosterone Range |
|---|---|
| 20 to 29 years old | 9.3 to 26.5 pg/mL |
| 30 to 39 years old | 8.7 to 25.1 pg/mL |
| 40 to 49 years old | 6.8 to 21.5 pg/mL |
| 50 to 59 years old | 7.2 to 24.0 pg/mL |
| > 59 years old | 6.6 to 18.1 pg/mL |
UF Health does not establish a range for males under age 20 with this assay.1 The table also does not show a uniform decade-by-decade decline. Its range for ages 50 to 59 is higher at both ends than the range for ages 40 to 49.
Other laboratories and methods publish different adult ranges:
| Laboratory and Method | Age Group | Male Free Testosterone Range |
|---|---|---|
| UF Health, equilibrium ultrafiltration | Adults | 5.00 to 21.00 ng/dL3 |
| University of Iowa, calculated free testosterone | 18 years and older | 32 to 168 pg/mL4 |
Sharing the name free testosterone does not put these ranges on one scale. The units differ, and the methods produce different results. Vermeulen and colleagues found that direct analog values were only a fraction of calculated or equilibrium dialysis values. The size of that difference varied with sex hormone-binding globulin (SHBG).2
Use the method, unit, and reference interval printed on your own report.
If one result falls outside the printed range, a physician looks for repeat morning measurements and the surrounding hormone pattern before deciding whether the finding is persistent.
Free and Total Testosterone in the Same Lab Picture
Free testosterone is the small fraction of testosterone circulating without a binding protein attached. The American Urological Association (AUA) states that approximately 2% circulates in this form. Most of the remaining testosterone is bound to albumin, SHBG, or other proteins.5
Total testosterone includes both bound and free testosterone. SHBG binds testosterone tightly,5 so a change in SHBG can alter the relationship between your total and free results. UF Health lists obesity, cirrhosis, and thyroid disorders among the clinical states that may alter testosterone-binding proteins.1
Because SHBG changes the link between total and free results, a total result near the lower end of its range may lead your physician to order free testosterone. The Endocrine Society also recommends free testosterone testing when a condition may alter SHBG.6 For age-based information about the total measurement, see testosterone levels by age.
A laboratory range does not establish whether you feel well or whether treatment would help. Your symptoms, total testosterone, free testosterone, SHBG, and testing conditions form the clinical picture.
Free Testosterone Measurement Methods
Free testosterone can be measured or estimated in several ways, and the method changes the number you receive.
Equilibrium dialysis was the comparison standard in Vermeulen and colleagues’ study.2 The Endocrine Society recommends obtaining free testosterone by equilibrium dialysis or estimating it with an accurate formula.6
Calculated free testosterone uses total testosterone and SHBG in a mathematical formula. The University of Iowa derives its free testosterone result from a binding equation.4 Vermeulen and colleagues found that free testosterone calculated from total testosterone and SHBG was almost identical to equilibrium dialysis values in every condition they studied except pregnancy.2
Direct analog immunoassay produces the age-banded UF Health ranges shown above. The AUA states that direct measurement of free testosterone is not reliable because of high assay variation. The AUA also does not recommend any free testosterone measurement as the primary diagnostic method for testosterone deficiency.5 Vermeulen and colleagues also found that analog values changed relative to calculated and equilibrium dialysis values as SHBG changed.2
Ask which method produced your result before comparing it with any free testosterone normal range online.
Age-Related Changes in Free Testosterone
Free testosterone tends to decline with age, and the Massachusetts and Baltimore aging studies measured that decline as a yearly rate or an index rather than a concentration for each decade.
The Massachusetts Male Aging Study followed men who were ages 40 to 70 at baseline. In follow-up data, free testosterone declined by about 2% per year in a cross-sectional analysis, while SHBG increased by 1.6% per year.7 Cross-sectional analysis compares men of different ages at the same measurement period. It does not predict the exact annual change in your own result.
The Baltimore Longitudinal Study of Aging also found an age-related decline in the free testosterone index among 890 men.8 That index was calculated by dividing total testosterone by SHBG. It was not a free testosterone concentration in pg/mL or ng/dL, so it cannot supply decade-specific ranges for your lab report.
Age provides context. Your current assay, unit, symptoms, and prior results provide the information needed to interpret your individual trend.
Physician Review After a Low Result
The Endocrine Society recommends free testosterone when total testosterone is near the lower limit of normal or a condition alters SHBG, and the AUA gives it a place in highly symptomatic men whose total testosterone is low-normal or equivocal.5,6
The Endocrine Society recommends starting with fasting morning total testosterone and confirming a low result with a second morning measurement.6 The University of Iowa advises collecting its testosterone specimen between 6:00 and 10:00 a.m.4 Learn more about timing and preparation for a testosterone blood test.
The AUA uses total testosterone below 300 ng/dL as a cutoff that supports a low-testosterone diagnosis. The guideline requires two early-morning total testosterone measurements on separate occasions and states that a result below 300 ng/dL alone does not define testosterone deficiency.5 The testosterone levels by age calculator can compare a total testosterone result with that AUA cutoff.
The AUA guideline sets no free testosterone cutoff that qualifies you for testosterone replacement therapy (TRT). Total and free testosterone are separate measurements, and the AUA does not treat them as interchangeable.5
The European Male Aging Study used a calculated free testosterone threshold below 220 pmol/L (64 pg/mL) as one part of a research definition in men ages 40 to 79. The definition also required total testosterone below 11 nmol/L and at least three sexual symptoms.9 That research threshold does not apply to the UF direct analog table or serve as a universal treatment cutoff.
If your result is low for the method used, the next step is a review of symptoms, testing time, total testosterone, SHBG, and repeat measurements. You can also review low testosterone symptoms and next steps before a physician consultation.
The Opt Take on Free Testosterone Levels by Age
An Opt Health physician reads your hormone results as a pattern, alongside your symptoms, health history, and current medications, before a plan is set. One isolated result cannot show that pattern.
An Opt Health membership starts with a panel of 55+ biomarkers collected at home or at a local partner lab. A 1:1 physician consultation follows. Your physician reads hormone results alongside inflammation, cardiovascular risk, and other markers covered in the biomarker guide. That review connects the laboratory reference interval to your symptoms and the rest of your results.
Full labs and a physician consultation repeat every 3 to 4 months. Your physician uses those trends to adjust the plan based on what your numbers did.
Get started: Begin with Opt Health, where a physician reads your labs, builds your plan, and adjusts it over the loop.
Frequently Asked Questions
Free testosterone estimates the small fraction of testosterone circulating without a binding protein attached. It can add information when total testosterone is near the lower end of normal or when SHBG may be altered.5,6
The result only has meaning when paired with its method, unit, laboratory range, and your symptoms. A physician will usually read it alongside total testosterone and SHBG.
The AUA guideline sets no free testosterone level that justifies TRT.5 The Endocrine Society recommends diagnosing hypogonadism only in men with symptoms and signs of testosterone deficiency and unequivocally and consistently low testosterone concentrations. It recommends repeated fasting morning total testosterone and free testosterone when total testosterone is borderline or SHBG may be altered.6
The AUA uses total testosterone below 300 ng/dL to support diagnosis, while also requiring symptoms and two early-morning total measurements on separate occasions.5 Treatment decisions depend on the complete clinical evaluation.
A free testosterone result of 4.2 cannot be interpreted without the unit, measurement method, age, and laboratory range. A value reported in pg/mL cannot be compared directly with a range reported in ng/dL.
If the report uses UF Health’s direct analog method and pg/mL, compare 4.2 pg/mL with the age band in the first table. If the report uses equilibrium ultrafiltration or a calculated method, use the interval printed by that laboratory instead.
Normal free testosterone by age is the age-specific reference interval for the assay used by your laboratory. UF Health’s direct analog range runs from 9.3 to 26.5 pg/mL at ages 20 to 29 and from 6.6 to 18.1 pg/mL after age 59.1
Those values do not apply to calculated free testosterone or equilibrium methods. For free testosterone levels by age, match your result to the method, unit, and reference interval on your report, then review the complete hormone pattern with your physician.
One free testosterone result cannot define your hormone pattern. An Opt Health membership pairs 55+ biomarkers with a 1:1 physician review, then repeats labs and a physician consultation every 3 to 4 months so your plan follows your results.
References
- UF Health Pathology Laboratories. Testosterone, Free (Direct). Accessed October 5, 2026. https://pathlabs.ufl.edu/tests/test-directory-t/testosterone-free-direct/
- Vermeulen A et al. A critical evaluation of simple methods for the estimation of free testosterone in serum. J Clin Endocrinol Metab. 1999;84(10):3666-3672. https://pubmed.ncbi.nlm.nih.gov/10523012/
- UF Health Pathology Laboratories. Testosterone, Free (Equilibrium Ultrafiltration) With Total Testosterone. Accessed October 5, 2026. https://pathlabs.ufl.edu/tests/test-directory-t/testosterone-free-equilibrium-ultrafiltration-with-total-testosterone/
- University of Iowa Health Care, Pathology Laboratory Services Handbook. Testosterone, Free and Total, Adult. Accessed October 5, 2026. https://www.healthcare.uiowa.edu/path_handbook/handbook/test1802.html
- Mulhall JP et al. Evaluation and management of testosterone deficiency: AUA guideline. J Urol. 2018;200(2):423-432. https://pubmed.ncbi.nlm.nih.gov/29601923/
- Bhasin S et al. Testosterone therapy in men with hypogonadism: an Endocrine Society clinical practice guideline. J Clin Endocrinol Metab. 2018;103(5):1715-1744. https://pubmed.ncbi.nlm.nih.gov/29562364/
- Feldman HA et al. Age trends in the level of serum testosterone and other hormones in middle-aged men: longitudinal results from the Massachusetts male aging study. J Clin Endocrinol Metab. 2002;87(2):589-598. https://pubmed.ncbi.nlm.nih.gov/11836290/
- Harman SM et al. Longitudinal effects of aging on serum total and free testosterone levels in healthy men. Baltimore Longitudinal Study of Aging. J Clin Endocrinol Metab. 2001;86(2):724-731. https://pubmed.ncbi.nlm.nih.gov/11158037/
- Wu FC et al. Identification of late-onset hypogonadism in middle-aged and elderly men. N Engl J Med. 2010;363(2):123-135. https://pubmed.ncbi.nlm.nih.gov/20554979/
This content is for informational purposes and does not replace evaluation, diagnosis, or treatment by a qualified medical professional.
This article is part of our guide to testosterone. See how physician-managed TRT works at Opt Health.
Start Today
Your health, your terms. Discover how personalized care can transform not just the way you feel, but how you live.