Testosterone Levels by Age: Normal Range and Meaning

Testosterone levels by age fall less steeply than most men assume. In harmonized reference data, median total testosterone in nonobese men was 531 ng/dL at ages 19 to 39 and 477 ng/dL from 50 onward. The top of the normal range barely moved with age. The bottom fell the most.

What Is a Normal Testosterone Level?

Two answers, and they get confused constantly. So let’s separate them.

The practical answer used in most clinics: a normal range for early morning testosterone in men runs roughly 300 to 1,000 ng/dL, though it varies by laboratory. Low testosterone is usually diagnosed when a morning serum testosterone level sits below 300 ng/dL on at least two occasions.

The research answer is more precise. A group of investigators harmonized testosterone assays across four large cohorts in the United States and Europe, calibrating them to a CDC reference method so the numbers could be compared. In healthy nonobese men aged 19 to 39, the harmonized percentiles were 264 ng/dL at the 2.5th, 303 at the 5th, 531 at the median, 852 at the 95th, and 916 at the 97.5th.

That gives a harmonized normal range of 264 to 916 ng/dL for young adult men. And it shows how wide normal is. Two healthy men in early adulthood can differ by more than 600 ng/dL and both be unremarkable. Which is worth sitting with before you compare your number to a friend’s.

Testosterone Levels by Age Chart

Here is the useful part, and it is rarely published with a real source attached. These are model-based percentile estimates of total testosterone in ng/dL from 6,933 nonobese men across the four harmonized cohorts.

Three things jump out of that table. Honestly, the second one surprised us.

The median barely moves after 50. A man of 75 and a man of 52 have the same median total testosterone level of 477 ng/dL. The steep part of the testosterone decline happens between the twenties and the fifties, then it flattens.

High testosterone levels stay available at every age. The 95th percentile sat between 839 and 850 ng/dL across every age group. Age does not put a ceiling on your number.

The bottom of the range falls furthest. The 5th percentile drops from 304 to 252 ng/dL by the seventies, and 218 after 80. So aging widens the low tail rather than shifting the whole distribution down.

Does Body Weight Matter More Than Age?

It matters a great deal. And the same dataset shows it cleanly.

The table above covers nonobese men. When obese men were included, every percentile dropped. Median total testosterone in all men aged 19 to 39 was 507 ng/dL rather than 531, and the 2.5th percentile fell from 267 to 229 ng/dL.

Fat tissue converts testosterone to estradiol through the aromatase enzyme, and it lowers sex hormone binding globulin. Both push a total testosterone level down.

So a 45-year-old carrying 40 extra pounds and a lean 45-year-old aren’t reading from the same distribution. In our clinic, the most reliable way we have seen men raise their own testosterone production is weight loss, and it is also the least popular answer.

Other lifestyle factors move the number too. Poor sleep, untreated sleep apnea, heavy alcohol use, opioid medication, and chronic illness all lower testosterone levels. These are worth fixing before you consider replacing anything.

Free Testosterone vs Total Testosterone

Total testosterone counts everything in the blood. Most of it is bound: tightly to sex hormone binding globulin, loosely to albumin. Free testosterone is the small unbound fraction. Bioavailable testosterone means free plus the albumin-bound portion.

For most men, total testosterone answers the question. MedlinePlus, from the National Library of Medicine, explains why the free fraction gets attention anyway: “Free testosterone is more available for your body to use when building bones and muscles,” it notes. Even so, measuring free testosterone levels is generally unnecessary unless a problem with the binding protein is suspected.

That said, the exceptions are common enough to matter.

• Obesity. Lowers binding globulin, which pulls total testosterone down while free testosterone holds up better.
• Older age. Binding globulin rises, so total can look reassuring while free testosterone is low.
• Thyroid disease. Moves binding globulin in both directions.
• Liver disease and diabetes. Both distort binding.
• Some medications. Anticonvulsants and estrogens raise binding globulin.

That is why a man of 68 with a total of 340 ng/dL and clear symptoms deserves a free testosterone measurement, while a lean man of 32 with the same number usually does not.

Assay quality varies too. Calculated free testosterone from total, binding globulin, and albumin is more reliable in general practice than most direct free testosterone immunoassays.

Why One Testosterone Test Is Not Enough

Because testosterone isn’t a stable number. It follows a daily rhythm, it varies week to week, and it drops during illness. So one draw is one moment, not a baseline.

The standard is two early morning serum testosterone measurements, drawn between 8 and 10 AM. Morning draws are used because levels are typically highest then.

Here’s what happens when men get the wrong answer. One draw at 3 PM, after a bad night’s sleep, during a chest infection, at a walk-in lab, then a diagnosis. That is a frustrating way to be handed a lifelong label. We have re-tested plenty of men whose second morning result came back 150 ng/dL higher than the first afternoon one.

A full testosterone testing panel includes more than one number. Before treatment we check two morning levels plus hemoglobin, hematocrit, PSA, prolactin, FSH, and LH. LH and FSH tell you whether the problem is in the testes or in the pituitary, and that changes the treatment options entirely.

When Is a Low Testosterone Level a Diagnosis?

When the number and the man agree. That’s the whole test, and in our experience it is the step most often skipped. Two total testosterone levels below 300 ng/dL establish biochemical testosterone deficiency. Clinical hypogonadism requires an associated symptom or sign, and only symptomatic men should be treated.

Symptoms that point most strongly at testosterone deficiency are specific.

1. Fewer spontaneous erections, especially morning ones.
2. Low libido that represents a change rather than a lifelong pattern.
3. Loss of muscle mass despite unchanged training.
4. Smaller testicular volume, which a physical exam catches.
5. Unexplained fatigue after sleep and iron have been checked.
6. Erectile dysfunction, though this has many other causes.

Non-specific complaints matter less. Low energy levels, irritability, and poor concentration are real, and they’re also produced by sleep debt, depression, thyroid disease, and anemia. In most cases treating those with testosterone doesn’t work.

Clinical judgment cuts both ways. A man with persistent symptoms of testosterone deficiency and levels in the normal range still deserves a proper workup rather than dismissal.

Do Testosterone Levels Really Decline With Age?

Yes. And the size of the decline gets exaggerated in both directions.

The harmonized data shows a median drop of about 54 ng/dL between the 19 to 39 group and men aged 50 and over, then almost nothing after that. That is a real change and a modest one. It is not the collapse that clinic advertising implies.

At the same time, the low end matters clinically. More men fall below the treatment threshold as the bottom of the distribution slides down, which is why testosterone deficiency is more common in older age groups even though the median holds steady.

What the numbers don’t settle is whether a level that’s low for a 70-year-old should be treated. The randomized evidence in older men found real but small benefits, mostly for sexual function, which we cover in our article on TRT before and after.

The Endocrine Society’s guidance on hypogonadism in men is worth reading before you draw conclusions from a single lab report.

What Raises Testosterone Naturally?

Some things genuinely work. Most of what’s advertised doesn’t, which is frustrating to explain for the fifth time in a week.

Losing excess body fat. The most effective non-medical lever, and it works through aromatase and binding globulin at once.

Treating sleep apnea. Fragmented sleep suppresses testosterone production directly. Men who start CPAP often see a real change.

Sleeping more. Testosterone is released largely during sleep, so short sleep lowers it.

Resistance training. Supports muscle mass and body composition, which supports healthy levels indirectly.

Reviewing your medications. Opioids and glucocorticoids suppress the axis. So does anabolic steroid use, which suppresses your own testosterone production long after the cycle ends.

Cutting heavy alcohol use. Regular heavy drinking lowers testosterone.

What does not have good evidence: most over-the-counter testosterone boosters. If your level is genuinely low and reversible causes have been treated, testosterone replacement therapy is a real option worth discussing. If it is not, a supplement will not change the number.

What Else Belongs on the Panel?

Testosterone is one hormone in a system. And reading it alone is how men get the wrong answer.

We look at several hormone levels together, because each one changes what a low number means.

• LH and FSH. High values point to the testes. Low or normal values with low testosterone levels point to the pituitary or hypothalamus, which needs its own workup.
• Prolactin. Elevated prolactin suppresses the whole axis, and a pituitary cause changes the treatment entirely.
• Estradiol. Some testosterone converts to estrogen, and that conversion rises with body fat.
• Thyroid function. Thyroid disease copies almost every symptom of low testosterone.
• Hematocrit and hemoglobin. Baseline values before any testosterone therapy, because treatment raises them.
• PSA. A baseline for men old enough to warrant prostate monitoring.
• Ferritin and a blood count. Iron deficiency produces the same fatigue that gets blamed on hormone production.

Symptoms deserve the same breadth. Sex drive, morning erections, and sexual health questions belong in the visit, and so do sleep, mood, and training. A man whose libido is intact but whose energy is gone is telling a different story than a man whose sex drive disappeared over two years.

Honestly, this is where most rushed evaluations fail. One number gets measured, a healthy testosterone level gets ruled out, and nobody asks what else could produce the same complaint. From what we’ve seen, that second question is where the answer usually is.

Testosterone Testing at Foundation Wellness

Our team measures properly before anyone discusses treatment. Two early morning draws, a full panel alongside them, and a conversation about your symptoms rather than only your number. Our patients arrive worried that one low result means a prescription for life, and that is not how a diagnosis gets made here.

Then we look for what else is going on. Plenty of the men we see with a borderline total testosterone level turn out to have untreated sleep apnea, iron deficiency, or a thyroid problem. Fixing those sometimes brings the number up on its own. When it does not, we have a much clearer case for treatment and a much better baseline to measure against.

If you already have a result and want it read properly, bring it. The draw time, the assay, and whether it was your first or second reading all change the interpretation. Bringing the printout is the single most useful thing our patients do before a first visit.

We are in American Fork and we see men across Utah County, from Provo up toward Salt Lake and along the Wasatch Front, in person and by telehealth. Start with TRT in Utah or what TRT is, read about TRT side effects before deciding, and look at our men’s health program for how we run it. Then reach out.

This article is general information about testosterone levels. It is not medical advice. Talk with a licensed clinician about your own labs and symptoms before starting hormone replacement therapy of any kind.

Frequently Asked Questions

How much do testosterone levels drop with age?

Less than most men expect, and unevenly. The upper end barely moves: the 95th percentile sat between 839 and 850 ng/dL at every age. The bottom of the range falls furthest, which is why the men who notice a decline tend to be the ones who started lower.

What testosterone level counts as low?

Most clinicians use a morning total testosterone below 300 ng/dL on at least two separate occasions, alongside symptoms, which is how Endocrine Society guidance frames the diagnosis. Two low numbers with no symptoms is a lab finding, not a diagnosis, and symptoms with normal numbers still need explaining.

Should I test free testosterone or total testosterone?

Total testosterone first, and the MedlinePlus overview of testosterone testing explains why. Free testosterone matters when something is distorting sex hormone binding globulin: obesity, thyroid disease, liver disease, diabetes, or older age. Ordering it routinely on everyone adds cost more often than clarity.

Does a testosterone level need to be drawn in the morning?

Yes. Levels peak in the early morning and fall through the day, so the standard is a draw between 8 and 10 AM. An afternoon result that looks low is often just an afternoon result.

Is a testosterone level of 400 ng/dL good?

It is comfortably normal at any age. In the harmonized data, 400 ng/dL sits near the 25th percentile for a man in his twenties or thirties and slightly above it for a man over 50. If you feel well, that number needs no action.

Can testosterone be too high?

Yes. Above the reference range, either from a supraphysiologic dose or rarely from a tumor, it raises hematocrit, suppresses fertility, and can worsen sleep apnea. High testosterone levels on treatment usually mean the dose or the timing of the draw needs adjusting.

Why do labs report different reference ranges?

Because assays differ, and most labs build their range from their own population rather than a harmonized standard. That is exactly the problem the harmonized reference project set out to solve. Compare results within one lab rather than across two.

Key Takeaways

• In harmonized reference data, median total testosterone in nonobese men was 531 ng/dL at ages 19 to 39 and 477 ng/dL from 50 onward.
• The harmonized normal range for healthy nonobese men aged 19 to 39 is 264 to 916 ng/dL.
• The 95th percentile stayed between 839 and 850 ng/dL at every age, so high testosterone remains available in later life.
• The 5th percentile fell from 304 to 252 ng/dL by the seventies, which is where age actually shows up.
• Obesity lowers every percentile, and losing body fat is the most reliable way to raise your own level.
• Low testosterone is generally defined as two morning readings under 300 ng/dL, and it needs symptoms to become a diagnosis.
• Free testosterone testing is worth adding when obesity, older age, thyroid disease, liver disease, or diabetes distorts binding globulin.
• Draw between 8 and 10 AM, twice, and never diagnose from one afternoon result.

Sources

• Travison TG et al., Harmonized Reference Ranges for Circulating Testosterone Levels in Men of Four Cohort Studies in the United States and Europe, Journal of Clinical Endocrinology and Metabolism, 2017.
• StatPearls, National Center for Biotechnology Information, Male Hypogonadism.
• Endocrine Society, hypogonadism in men.
• MedlinePlus, National Library of Medicine, Testosterone Levels Test.
• U.S. Food and Drug Administration, class-wide labeling changes for testosterone products, February 28, 2025.