Normal testosterone levels by age

What is a normal testosterone level?

Testosterone is measured in blood in nmol per liter, and what counts as normal depends on age. Swedish laboratories divide adult men into two age groups. The reference intervals below are used in Swedish laboratory medicine, among others by Region Västmanland.

Intervals can differ somewhat between laboratories and assay methods, so the interval printed on your own report is the one that applies to your value. Two things are worth noticing. The span is wide, a perfectly healthy 30 year old can sit at 9 just as well as at 28. And the lower limit drops after 50, reflecting that levels slowly taper with age.

How does testosterone change with age?

The decline is gradual rather than sudden. In the European ageing study EMAS, which followed just over 3000 men aged 40 to 79 across eight countries, total testosterone fell by roughly 0.4 percent per year on average. Free testosterone fell faster, about 1.3 percent per year, because SHBG (the protein that binds testosterone in the blood) rises with age at the same time.

Part of the decline is also about more than birth year. Excess weight, chronic illness and certain medicines become more common over the years and pull testosterone down alongside them. Many older men therefore stay well within the reference interval, while a younger man with health problems can sit low.

When does a value count as low?

Swedish clinical guidance, most recently issued in 2026 by the Västra Götaland region, draws the lines like this. At a value above 12 nmol per liter, testosterone deficiency is very unlikely. Values between 8 and 12 count as a gray zone, and values below 8 point toward probable deficiency.

A single low value is never enough for a diagnosis. The guideline requires symptoms combined with at least two low values taken fasting in the morning, and low values are followed up with SHBG and LH (the pituitary signal to the testes) to explain why the value sits where it does. A low total value alongside a low SHBG, for example, need not mean deficiency at all.

What affects the value more than age?

Testosterone swings considerably over the day, with the highest levels in the morning and before noon. A meal can also lower the value temporarily for a few hours. That is why the sample should be taken fasting, early in the day, if it is to be compared against the reference interval.

Beyond the daily rhythm, lack of sleep, acute illness, hard physical effort and stress can push values down temporarily. More lastingly, excess weight and obesity lower the level, as do certain medicines, among them opioids and cortisone, along with past or ongoing use of anabolic steroids. An unexpectedly low value always deserves a retest before it is given any weight.

How is testosterone tested?

Testosterone Basics measures total testosterone, SHBG and albumin. SHBG and albumin provide binding-protein context. A separate free or bioavailable testosterone result and a testosterone/SHBG ratio are not included.

Sample fasting at 07:00-10:00 after normal sleep, following the order instructions. When symptoms or a borderline result call for more assessment, a clinician selects the next tests. A low result usually needs confirmation on another morning.

When should you see a doctor?

See a doctor if you have symptoms that suggest testosterone deficiency, above all reduced desire, fewer morning erections or erectile problems, especially in combination with a measured low value. More diffuse complaints such as long-standing lack of energy, low mood or shrinking muscle mass can also be reason to raise the question with a doctor.

An article like this can help you understand your report, but it can never make a diagnosis. Assessing testosterone deficiency takes repeated samples, complementary values and a doctor who weighs the whole picture.

Testosterone Basics includes total testosterone, SHBG and albumin. It does not include a separate free or bioavailable testosterone analysis or a testosterone/SHBG ratio. Sample fasting at 07:00-10:00 according to the order.

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This article is general health information, not medical advice and not an assessment of your values. If you have symptoms or concerns, contact your healthcare provider.