Updated
Normal testosterone levels depend on the laboratory, test method, age, and clinical context. As one laboratory example, Mayo Clinic Laboratories lists adult total testosterone reference intervals of 240–950 ng/dL for men and 8–60 ng/dL for women age 19 and older. These are reference intervals, not universal treatment targets. A result must be interpreted alongside symptoms and the conditions of testing. [1,2]
What your result can tell you
- Check whether the test measured total or free testosterone.
- Use the units and reference interval printed on that report.
- In men, a diagnosis of testosterone deficiency requires compatible symptoms or signs and consistently low results.
- Free testosterone and SHBG can help in selected cases; they are not automatically a required panel for everyone.
- A single number does not establish a need for supplements or testosterone therapy.
Normal testosterone ranges: why the numbers differ
| Reference population | Total testosterone | How to interpret it |
|---|---|---|
| Men age 19+; Mayo laboratory example | 240–950 ng/dL | An interval for a particular laboratory method |
| Women age 19+; Mayo laboratory example | 8–60 ng/dL | An interval for that test, not a threshold defining a female deficiency syndrome |
| Healthy, nonobese men ages 19–39; harmonized research cohort | 264–916 ng/dL | A research-derived interval using standardized measurements |
The research interval comes from a study that harmonized results across four cohorts. Differences between assays accounted for some of the variation between studies. That is one reason online charts and your own laboratory may show different limits. [1,3]
The American Urological Association uses below 300 ng/dL as a reasonable cutoff supporting a diagnosis of low testosterone in men, together with symptoms or signs and repeat morning testing. This clinical cutoff serves a different purpose from a population reference interval. [4]
“Within range” and “needs treatment” are different questions. There is no established universal “optimal” target of 500–900 ng/dL for every man. A clinician considers the result, symptoms, medical history, and test reliability rather than trying to move everyone to the top of a chart.
Total testosterone vs free testosterone vs SHBG
Total testosterone includes hormone circulating both bound to proteins and unbound. Most is attached to proteins, including sex hormone-binding globulin (SHBG) and albumin. Free testosterone is the unbound fraction; “bioavailable” testosterone generally includes free and loosely albumin-bound testosterone. [1,5]
| Test or marker | What it measures | Why it matters |
|---|---|---|
| Total testosterone | Bound plus unbound testosterone | Usually the starting measurement when evaluating suspected deficiency in men |
| Free testosterone | Unbound testosterone | Can clarify selected borderline results or situations with altered SHBG |
| SHBG | A protein that binds testosterone | Helps explain why total and free results may differ |
| Bioavailable testosterone | Free plus loosely protein-bound testosterone, mainly albumin-bound | A different measurement from total or free alone |
The Endocrine Society recommends assessing free testosterone in men when total testosterone is near the lower limit or a condition alters SHBG. Suitable approaches include equilibrium dialysis or a validated calculation using total testosterone, SHBG, and albumin. Free-testosterone reference ranges depend on the method; there is no single interchangeable cutoff for every assay. [2]
For example, two people can have similar total testosterone but different free testosterone when their binding-protein levels differ. That does not mean that lowering SHBG is automatically a treatment goal. The results need to be understood together.
How do testosterone levels change with age?
Age matters, but a decade-by-decade online chart cannot establish your personal target. Puberty, adult aging, health conditions, medications, and the laboratory method affect interpretation. Children and adolescents require age- and development-appropriate ranges; adult numbers should not be applied to them. [1,5]
In men, testosterone often declines with age, but persistent symptoms should not automatically be dismissed as aging—or automatically attributed to testosterone. The Endocrine Society's 2026 statement reinforces the need for an accurate clinical diagnosis. In women, menstrual and menopausal status and hormone use can affect the clinical context. Your clinician can explain which reference population is appropriate. [5,7]
How to read your testosterone blood test
- Identify the measurement. Total and free testosterone are different tests. Do not compare one with the other's interval.
- Check the units. Total testosterone may appear in ng/dL or nmol/L; free testosterone may appear in pg/mL or ng/dL.
- Use the report's interval. Keep the laboratory name and test method when comparing results over time.
- Record the collection conditions. Include the collection time, fasting instructions, recent illness, and medicines or supplements you take.
- Discuss the pattern. Ask whether repeat testing or additional evaluation is needed before drawing conclusions.
A unit-conversion example
For testosterone, ng/dL × 0.0347 ≈ nmol/L. A total testosterone result of 400 ng/dL is approximately 13.9 nmol/L. The number changed because the unit changed, not because the hormone level changed.
For mass units, 1 ng/dL equals 10 pg/mL. Converting units does not make total and free testosterone equivalent tests.
When should men repeat a low result?
For suspected testosterone deficiency, the Endocrine Society recommends confirming a low result with a repeat morning, fasting total testosterone measurement. Testing during an acute illness can be misleading. A clinician should decide whether a borderline result warrants a reliable free-testosterone assessment and whether further testing is needed to identify the cause. [2,7]
Reduced sexual desire, changes in erections, infertility, or unexplained changes in bone or muscle health may justify evaluation. Fatigue alone has many possible causes and does not diagnose low testosterone. Read low testosterone symptoms for more context. [4,5]
What do high or low testosterone results mean in women?
A low number alone does not establish a testosterone-deficiency syndrome in an otherwise healthy woman. The Endocrine Society advises against that diagnosis because a well-defined syndrome and reliable links between a specific level and symptoms are lacking. This does not mean symptoms should be ignored; it means the evaluation should be broader than one hormone number. [6]
New facial or body hair growth, irregular periods, acne, scalp hair loss, or voice changes can warrant assessment for androgen excess. A high result is a reason to investigate the cause, not proof of one particular condition. Discuss persistent or rapidly changing symptoms with a qualified healthcare professional. [5]
Can lifestyle changes or supplements fix low testosterone?
The next step depends on the cause. Review sleep, nutrition, training load, medications, and underlying health conditions with your clinician. Do not stop a prescribed medicine or start hormone treatment based on a blog chart. Testosterone therapy also has implications for fertility that deserve a specific discussion before treatment. [2,4]
Evidence about an individual supplement ingredient does not establish that a finished product treats testosterone deficiency. Nor does it prove that a healthy person should raise an already-normal result. Supplements should not delay assessment of persistent symptoms or abnormal tests.
Frequently asked questions
Is 300 ng/dL normal for a man?
It is near a commonly used clinical cutoff, but one result does not settle the diagnosis. Symptoms, repeat morning measurements, the assay, and sometimes free testosterone help determine the next step. [2,4]
Can total testosterone be normal while free testosterone is low?
Yes, altered binding-protein levels can produce that pattern. Confirm the method and reference interval with your clinician rather than interpreting a free result against a total-testosterone chart. [2]
Should everyone buy a large hormone-testing panel?
No. Testing should answer a clinical question. The Endocrine Society advises against routine screening for testosterone deficiency in asymptomatic men. [7]
Considering a supplement? Start with the label.
Review Rise's ingredients and serving information with your healthcare professional if you are considering it. Rise is a dietary supplement, not a treatment for diagnosed testosterone deficiency or a replacement for medical evaluation.
Review Rise ingredients and directionsSources
- Mayo Clinic Laboratories. Testosterone, total and free, serum: reference values and interpretation.
- Bhasin S, et al. Testosterone therapy in men with hypogonadism: Endocrine Society clinical practice guideline. 2018. Full guideline.
- Travison TG, et al. Harmonized reference ranges for circulating testosterone levels. JCEM. 2017.
- American Urological Association. Evaluation and management of testosterone deficiency.
- MedlinePlus. Testosterone levels test.
- Endocrine Society. Androgen therapy in women: a reappraisal. 2014.
- Endocrine Society. Statement on testosterone replacement therapy. July 2026.
