A normal testosterone level in adult men sits roughly between 9 and 30 nmol/L, measured in fasting morning blood. A single result says little: testosterone fluctuates across the day and per moment. So a doctor reads your value together with your symptoms, and repeats a low result before drawing conclusions.
Honestly? Testosterone is the hormone many men only look at once they have had less energy or drive for a while. Below you will read what the value means and how to measure it usefully.
To look beyond this one hormone, read which hormones you can have tested in a blood test.
What is testosterone and what does it do?
Testosterone is the main male sex hormone. It is produced mostly in the testicles and steers sperm production, your muscle mass, bone density, body hair and your libido (Nassar & Leslie, StatPearls).
Your mood and energy are partly linked to it too. Women also produce testosterone, by the way, but in much smaller amounts.
From around age 30, testosterone falls very gradually in most men, by about 1 to 2 percent a year. That is normal and does not on its own mean a deficiency.
What is a normal testosterone level in men?
A healthy man aged 19 to 39 sits, according to harmonized reference values, roughly between 9 and 32 nmol/L (264 to 916 ng/dL) total testosterone (Travison et al., 2017, PMID 28324103). Reference values differ per laboratory and per age, so your doctor always reads your result in context.
| Situation | Total testosterone (indication) | What it can mean |
|---|---|---|
| Healthy man, 19-39 years | About 9-32 nmol/L | Harmonized reference range (Travison et al., 2017) |
| Borderline value | Around 8-12 nmol/L | Grey zone; repeat the test in the morning |
| Repeatedly low, with symptoms | Below ~8 nmol/L | Discuss with your doctor; may point to a deficiency |
| Above the range | Above ~32 nmol/L | Sometimes from supplements or timing; your doctor reviews it |
With ageing the average slowly shifts down. A 55-year-old sits lower on average than a 25-year-old, while both can be healthy.
What are the symptoms of low testosterone?
Low testosterone can show in different ways, but no single symptom proves it on its own. The Endocrine Society advises only calling it a deficiency when symptoms and repeatedly low values occur together (Bhasin et al., 2018, PMID 29562364).
- Less interest in sex and weaker erections
- Persistent tiredness and less energy
- Loss of muscle strength or more belly fat
- Low mood, irritability or poorer sleep
Many of these complaints also fit stress, lack of sleep or a thyroid out of balance. Persistent tiredness often comes from long-term stress, for example; what you can see of that in your blood is in our article on cortisol, the stress hormone.
Free testosterone and SHBG: why one number is not enough
Most of your testosterone is bound to proteins in your blood, mainly to SHBG (sex hormone binding globulin). Only the small, free part is directly active. So your total testosterone can look normal while the free part is low.
A high SHBG, for example with ageing or an overactive thyroid, binds away more testosterone. With overweight or insulin resistance, SHBG is often lower instead.
So when in doubt, doctors measure SHBG and free testosterone alongside total testosterone.
When and how should you test testosterone?
The timing decides whether your result holds up. Testosterone is highest in the morning, so it is preferably drawn fasting between 7 and 11 am, and repeated once if the result is low (Bhasin et al., 2018, PMID 29562364).
- In the morning - between about 7 and 11 am, when your value peaks
- Fasting - eating can lower your testosterone temporarily
- Not during illness - an infection or heavy stress temporarily depresses the value
- Repeat a low result - one low number is not yet a diagnosis
The patient website Thuisarts.nl advises discussing any complaints that might point to a deficiency with your GP, precisely because the interpretation of the result makes the difference. If you want it measured, at Vital Check you can do a hormone test for men that includes testosterone.
Curious about the female counterpart to this story? Then read about oestrogen and menopause.
Frequently asked questions
Do I need to fast for a testosterone test?
Fasting in the morning is preferred. Eating can lower your testosterone temporarily, so a non-fasting result can come out lower than your real value.
Is a low testosterone value always a problem?
No. A low value without symptoms is usually no cause for concern. Doctors only speak of a deficiency when symptoms and repeatedly low values occur together.
Can I have my testosterone tested myself?
Yes. At Vital Check you can have testosterone measured as part of a hormone test. Just choose a morning slot for a reliable result.
What is the difference between total and free testosterone?
Total testosterone is all the testosterone in your blood, bound and free. Free testosterone is the small part that is directly active and not bound to proteins.
References
- Nassar GN, Leslie SW. Physiology, Testosterone. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2026. NCBI Bookshelf: NBK526128.
- Bhasin S, Brito JP, Cunningham GR, et al. Testosterone Therapy in Men With Hypogonadism: An Endocrine Society Clinical Practice Guideline. J Clin Endocrinol Metab. 2018;103(5):1715-1744. PMID: 29562364.
- Travison TG, Vesper HW, Orwoll E, et al. Harmonized Reference Ranges for Circulating Testosterone Levels in Men of Four Cohort Studies in the United States and Europe. J Clin Endocrinol Metab. 2017;102(4):1161-1173. PMID: 28324103.
Every blood test result at Vital Check includes a professional assessment from a BIG-registered doctor. A blood test does not make a diagnosis. For treatment decisions, discuss your results with your GP.
Frequently asked questions
Do I need to fast for a testosterone test?
Fasting in the morning is preferred. Eating can lower your testosterone temporarily, so a non-fasting result can come out lower than your real value.
Is a low testosterone value always a problem?
No. A low value without symptoms is usually no cause for concern. Doctors only speak of a deficiency when symptoms and repeatedly low values occur together.
Can I have my testosterone tested myself?
Yes. At Vital Check you can have testosterone measured as part of a hormone test. Just choose a morning slot for a reliable result.
What is the difference between total and free testosterone?
Total testosterone is all the testosterone in your blood, bound and free. Free testosterone is the small part that is directly active and not bound to proteins.
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