Last updated: August 2026. Written by Daniel Lazarevic. Fact-checked by Erik Johansson. This content does not replace medical advice.
Measuring testosterone: blood test, reference values and what they mean
Testosterone is measured with a blood test, ideally taken in the morning (around 7–10 a.m.) when levels are at their highest. Usually total testosterone is measured, and where needed free testosterone as well as SHBG (the protein that binds testosterone). A single value should always be interpreted together with symptoms and is best confirmed with a repeat test.
Here we go through how the sample is taken, the difference between free and total, approximate reference values and what you can do if the value is low.
Why and when to measure testosterone?
Measuring may be worthwhile if you have symptoms consistent with low testosterone: reduced libido, fatigue, poorer recovery, low mood or reduced muscle mass. Read more about signs and causes of low testosterone. Do not test "just to be safe" without symptoms – the result is then hard to interpret.
Total vs free testosterone (and SHBG)
Most of the testosterone in the blood is bound to protein and therefore not directly available to the body:
- Total testosterone: all testosterone, both bound and free. The most common first test.
- Free testosterone: the small proportion (usually 1–3 %) that is unbound and active.
- SHBG: the protein that binds testosterone. High SHBG can result in low free testosterone despite a normal total value.
Reference values by age
Reference ranges vary between laboratories, but approximate values for total testosterone in adult men:
| Age | Approximate reference range (total) |
|---|---|
| 19–49 years | approx. 9–30 nmol/L |
| 50+ years | often somewhat lower |
Always use the reference range that your own laboratory states on the test result, as the methods differ.
How the sample is taken correctly
- Take the sample in the morning, when testosterone is at its highest.
- Avoid hard exercise and acute illness in the days before – both can affect the value.
- Confirm a low value with a repeat test before drawing conclusions.
What you can do if the value is low
If the value is low and you have symptoms, a doctor should investigate the cause. In parallel, lifestyle can make a big difference – sleep, exercise, diet and stress. Our guide on increasing testosterone naturally goes through what is supported by research. Avoid self-diagnosing based on a single test.
Frequently asked questions (FAQ)
What is a normal testosterone value?
For adult men, total testosterone is often around 9–30 nmol/L, but the reference range varies between laboratories and with age.
What is the difference between free and total?
Total is all the testosterone in the blood; free is the small unbound proportion that is biologically active. SHBG affects how much is free.
What time of day should the sample be taken?
In the morning, around 7–10 a.m., when levels are at their highest.
What counts as low testosterone?
A value below the laboratory's reference range, together with symptoms. A low value without symptoms needs to be confirmed and interpreted by a doctor.
Can you raise it naturally?
Yes, sleep, strength training, weight control and stress management can affect the levels. See the guide on increasing testosterone naturally.
Test results should be interpreted by healthcare professionals. This text is general information, not individual medical advice.
