What Is a Normal Testosterone Level for a 40 Year Old Male? The Age-Specific Range, the 300 Cutoff and Why One Result Is Not Enough
Lab reports print one reference range for every adult man. The research on men in their early forties tells a more useful story, and it starts with when the blood was drawn.
A normal testosterone level for a 40 year old male sits roughly in the 350 to 473 ng/dL band, the middle third of morning values for US men aged 40 to 44 in a 2022 Journal of Urology analysis. That band is the middle third, not the full healthy range. The AUA uses 300 ng/dL as a cut-off supporting low testosterone, and a diagnosis needs two morning tests plus symptoms.
What is a normal testosterone level for a 40 year old male? In US national survey data analysed by Zhu and colleagues in the Journal of Urology (2022), the middle third of morning total testosterone values for men aged 40 to 44 ran from 350 to 473 ng/dL. Most laboratories print a much wider adult range, and the American Urological Association (AUA) treats a total testosterone below 300 ng/dL as a reasonable cut-off in support of a low testosterone diagnosis.
Those numbers answer different questions. The 350 to 473 ng/dL band describes what is typical for men in their early forties. The 300 ng/dL line describes where doctors start to suspect deficiency. Neither one, on its own, says whether a particular man has a problem. That depends on the time of the blood draw, the assay, body weight, symptoms and whether a second test agrees with the first.
350 to 473 ng/dL
Middle Third of Morning Total T, Men 40 to 44
NHANES 2011-2016, Zhu et al., J Urol 2022
300 ng/dL
AUA Cut-Off Supporting a Low T Diagnosis
AUA Statement 1 (Moderate, Grade B)
264 to 916 ng/dL
Harmonized Range, Healthy Nonobese Men 19 to 39
Travison et al., JCEM 2017
20-25%
Lower in the Late Afternoon Than Early Morning
Men 30 to 40, Brambilla et al., JCEM 2009
2
Separate Early Morning Tests Before a Diagnosis
AUA Statement 2 (Strong, Grade A)
What Is a Normal Testosterone Level for a 40 Year Old Male?
A normal testosterone level for a 40 year old male is roughly 350 to 473 ng/dL if normal means the middle third of men his age. Zhu and colleagues took this definition of a normal level, the middle tertile, from the AUA, and applied it to the 2011-2016 National Health and Nutrition Examination Surveys (NHANES). They excluded men on hormonal medication and men whose blood was drawn in the afternoon or evening, leaving 1,486 men aged 20 to 44.
The Zhu analysis also produced an age-specific cutoff for low testosterone: 350 ng/dL for men aged 40 to 44. That figure sits above the conventional 300 ng/dL line. The authors argued that a single age-indiscriminate cutoff, developed from samples of older men, does not fit younger men well. Their data stop at age 44, so the band applies to the early forties, not to men later in the decade.
Normal (Middle Tertile) Morning Total Testosterone by Age Group
| Age Group | Middle Tertile (ng/dL) | Age-Specific Low T Cutoff (ng/dL) |
|---|---|---|
| 20-24 | 409-558 | 409 |
| 25-29 | 413-575 | 413 |
| 30-34 | 359-498 | 359 |
| 35-39 | 352-478 | 352 |
| 40-44 | 350-473 | 350 |
Age-Specific Cutoff for Low Testosterone, US Men 20 to 44
What Should a 40 Year Old Man's Testosterone Level Be on a Lab Report?
On a lab report, a 40 year old man's total testosterone should usually fall inside the laboratory's printed reference range and, ideally, above 300 ng/dL. The printed range is wide because it covers the spread of healthy men rather than the average. In a 2017 harmonization study led by Travison, testosterone from 9054 community-dwelling men in four US and European cohorts was calibrated against a CDC reference method. In healthy nonobese men aged 19 to 39, the 2.5th to 97.5th percentile range was 264 to 916 ng/dL, with a median of 531 ng/dL.
The Travison study matters for men reading their own results because it found that a substantial proportion of the variation between cohorts came from assay differences. Two labs can report different numbers for the same blood. A man comparing results over time gets a cleaner picture by using the same laboratory, and by asking whether that lab's assay is calibrated to a reference standard.
A second reference model gives similar answers in international units. Kelsey and colleagues pooled data from thirteen studies of healthy men (PLoS One, 2014). Mean total testosterone peaked at 15.4 nmol/L at about age 19 and fell to 13.0 nmol/L by age 40, with a 2.5th to 97.5th percentile range of 6.6-25.3 nmol/L at that age. The model found no evidence of a further fall in the mean after 40, but the spread between men grew wider with age.
What the Main Reference Sources Say About Testosterone Around Age 40
| Source | Population | What It Reports |
|---|---|---|
| Zhu et al., J Urol 2022 | 1,486 US men aged 20 to 44, morning draws | Middle tertile 350-473 ng/dL at 40-44 |
| Travison et al., JCEM 2017 | 9054 men in four cohorts | 264 to 916 ng/dL in healthy nonobese men 19 to 39 |
| Kelsey et al., PLoS One 2014 | Thirteen studies of healthy men | Mean 13.0 nmol/L (6.6-25.3) by age 40 |
| AUA guideline | Clinical guidance | Below 300 ng/dL supports a low T diagnosis |
| Wu et al., NEJM 2010 (EMAS) | 3369 men aged 40 to 79 | Late-onset hypogonadism: three sexual symptoms plus total T under 11 nmol/L and free T under 220 pmol/L |
Does Testosterone Drop After 40?
Testosterone does tend to drop after 40, but slowly, and the speed depends heavily on health. The Massachusetts Male Aging Study (MMAS) followed men who were 40 to 70 at enrollment. Feldman and colleagues reported in 2002 that, of 1,709 men enrolled, 1,156 were tested again 7-10 years later. Comparing men of different ages, total testosterone fell 0.8% per year of age and free testosterone about 2% per year. Tracking the same men over time, total testosterone fell 1.6% per year and bioavailable testosterone 2-3% per year.
The MMAS also found that apparent good health, meaning no chronic illness, prescription medication, obesity or excessive drinking, added 10-15% to the level of several androgens. Sex hormone-binding globulin (SHBG), the protein that holds testosterone in the blood, rose 1.6% per year. A rising SHBG is one reason free testosterone falls faster than total testosterone as men age.
Yearly Change in Hormones With Age, Massachusetts Male Aging Study
Testosterone levels also appear lower across whole generations of young men. Lokeshwar and colleagues analysed NHANES data on 4045 men from 1999 to 2016 and found that mean total testosterone was lower in the 2011-2016 cycles than in 1999-2000, and lower with higher body mass index. The study covered adolescents and young adults, so it does not set a range for 40 year olds, but it is a reason to be cautious with reference ranges built from older data.
How Much Does Body Weight Change Testosterone at 40?
Higher body weight is linked to noticeably lower testosterone in men 40 and over. In the European Male Aging Study (EMAS), Wu and colleagues measured hormones in 3200 men aged 40-79 (JCEM, 2008). Compared with men whose BMI was under 25, total testosterone was 2.32 nmol/L lower in men with a BMI of 25 to 30 and 5.09 nmol/L lower in men with a BMI of 30 or more. Age itself was linked to lower free testosterone of 3.12 pmol/L per year.
How Much Lower Total Testosterone Was by BMI Group, EMAS
The same pattern shows up in directly measured free testosterone. Walravens and colleagues set reference ranges for free testosterone measured by equilibrium dialysis in 1202 men (JCEM, 2026). Compared with a BMI of 22, a BMI of 30 lowered measured free testosterone by 14.4% and a BMI of 35 by 22.2%. Both studies are cross-sectional: they show that heavier men have lower testosterone, not that losing weight raises it in any one man. Our article on sleep apnea and testosterone looks at another factor worth ruling out when levels keep testing low.
Is Total Testosterone Enough, or Should Free Testosterone Be Checked?
Total testosterone is the right first test, but free testosterone should be checked when total testosterone is borderline. The Endocrine Society's 2018 guideline, led by Bhasin, recommends measuring fasting morning total testosterone with an accurate and reliable assay, repeating it to confirm, and obtaining free testosterone in men whose total testosterone is near the lower limit of normal or who have a condition that alters SHBG.
EMAS data show why. Antonio and colleagues (JCEM, 2016) grouped 3334 men aged 40-79 by total testosterone (normal at 10.5 nmol/L or above) and calculated free testosterone (normal at 220 pmol/L or above). Men with normal total but low free testosterone were older, had higher SHBG and LH, and reported more sexual and physical symptoms. Men with low total but normal free testosterone were younger and more obese, and lacked the features of androgen deficiency.
EMAS Men 40 to 79 by Total and Calculated Free Testosterone (Antonio et al., JCEM 2016)
- Normal total, normal free (2641 men)
- Normal total, low free (277 men)
- Low total, normal free (96 men)
- Low total, low free (320 men)
The pie chart above uses the group counts reported by Antonio and colleagues for 3334 EMAS men. The small group with low total but normal free testosterone is the one most likely to be misread: their low total number mostly reflected low SHBG, often linked to obesity. Calculated and directly measured free testosterone can differ, so it helps to know which one a lab report shows.
Why Does the Time of the Blood Test Change the Result?
The time of the blood test changes the result because testosterone peaks in the morning and falls through the day, and the swing is largest in younger men. Brambilla and colleagues sampled 66 men aged 30 to 80 at morning and afternoon visits (JCEM, 2009). In men 30-40, testosterone was 20-25% lower at 1600 h than at 0800 h. The difference shrank with age, to about 10% at 70.
The Brambilla study found 17 men who had at least one afternoon result under 300 ng/dl (10.4 nmol/liter) but normal levels at all three morning visits. That is why the AUA says the diagnosis of low testosterone should be made only after two total testosterone measurements taken on separate occasions, both in the early morning. A single afternoon result below 300 ng/dL tells a 40 year old man very little.
Illustration: How a Single Testosterone Result Becomes a Diagnosis, or Doesn't
Test 1
Early morning total T
Fasting, drawn early in the morning, ideally at a lab using an accurate assay.
Test 2
Repeat on a separate morning
The AUA requires two early morning measurements on separate occasions before a diagnosis.
Borderline?
Add free testosterone
The Endocrine Society advises free T when total T is near the lower limit or SHBG is abnormal.
Symptoms
Match numbers to symptoms
The AUA makes the clinical diagnosis only when low total T is combined with symptoms and/or signs.
When Is a Testosterone Level at 40 Considered Low?
A testosterone level at 40 is considered low, in clinical terms, when two early morning total testosterone results fall below 300 ng/dL and the man has symptoms or signs that fit. AUA Statement 3 says the clinical diagnosis of testosterone deficiency is only made when patients have low total testosterone combined with symptoms and/or signs. A low number without symptoms, or symptoms with a normal number, does not meet that definition.
The EMAS investigators tried to pin down which symptoms actually track with testosterone in men 40 to 79. In the NEJM in 2010, Wu and colleagues found that only three sexual symptoms, poor morning erections, low sexual desire and erectile dysfunction, had a syndromic link with low testosterone. Their definition of late-onset hypogonadism required at least three sexual symptoms with total testosterone under 11 nmol/L (3.2 ng per milliliter) and free testosterone under 220 pmol/L. The probability of these symptoms started rising with total testosterone in the 8.0 to 13.0 nmol/L range.
Normal Is a Range, Not a Target
A man of 40 whose morning total testosterone sits inside the 350 to 473 ng/dL band and who has no symptoms is in the middle of the range Zhu and colleagues described for his age group. A man near the bottom of that band with a BMI of 30 or more belongs to a group that, in the EMAS and Walravens data, tends to have lower testosterone. Neither man is a candidate for treatment on the number alone. Lifting weights, getting enough sleep and building aerobic fitness with zone 2 cardio support overall health whatever the result.
Illustration: Getting a Testosterone Number You Can Trust at 40
Before the Test
- ✓Book an early morning appointment
- ✓Fast beforehand, as the Endocrine Society recommends
- ✓Avoid testing during an acute illness
First Result
- ✓Compare it with the lab's printed range and the 300 ng/dL line
- ✓Note the assay and the lab name
- ✓Write down any symptoms honestly
Second Result
- ✓Repeat at the same lab if possible
- ✓Ask about free testosterone and SHBG if total T is borderline
- ✓Ask whether LH and FSH are needed to find a cause
Next Steps
- ✓Review weight, sleep, alcohol and medications with a doctor
- ✓Screen for sleep apnea if snoring or daytime fatigue are present
- ✓Retest after lifestyle changes rather than guessing
This article is for educational purposes only and is not medical advice. It does not diagnose, treat, cure or prevent any disease. Reference ranges vary between laboratories, so interpret any result with the clinician who ordered it, and speak with a licensed physician before starting or changing any medication or hormone therapy.
Sources
- Zhu A et al. What Is a Normal Testosterone Level for Young Men? Rethinking the 300 ng/dL Cutoff for Testosterone Deficiency in Men 20-44 Years Old. Journal of Urology, 2022. https://doi.org/10.1097/JU.0000000000002928
- 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. https://doi.org/10.1210/jc.2016-2935
- Kelsey TW et al. A validated age-related normative model for male total testosterone shows increasing variance but no decline after age 40 years. PLoS One, 2014. https://doi.org/10.1371/journal.pone.0109346
- Feldman HA et al. Age trends in the level of serum testosterone and other hormones in middle-aged men: longitudinal results from the Massachusetts male aging study. Journal of Clinical Endocrinology and Metabolism, 2002. https://doi.org/10.1210/jcem.87.2.8201
- Wu FC et al. Hypothalamic-pituitary-testicular axis disruptions in older men are differentially linked to age and modifiable risk factors: the European Male Aging Study. Journal of Clinical Endocrinology and Metabolism, 2008. https://doi.org/10.1210/jc.2007-1972
- Wu FC et al. Identification of late-onset hypogonadism in middle-aged and elderly men. New England Journal of Medicine, 2010. https://doi.org/10.1056/NEJMoa0911101
- Antonio L et al. Low Free Testosterone Is Associated with Hypogonadal Signs and Symptoms in Men with Normal Total Testosterone. Journal of Clinical Endocrinology and Metabolism, 2016. https://doi.org/10.1210/jc.2015-4106
- Walravens J et al. Age-Stratified Reference Ranges for Directly Measured Serum Free Testosterone in Community-Dwelling and Healthy Men. Journal of Clinical Endocrinology and Metabolism, 2026. https://doi.org/10.1210/clinem/dgaf507
- Brambilla DJ et al. The effect of diurnal variation on clinical measurement of serum testosterone and other sex hormone levels in men. Journal of Clinical Endocrinology and Metabolism, 2009. https://doi.org/10.1210/jc.2008-1902
- Bhasin S et al. Testosterone Therapy in Men With Hypogonadism: An Endocrine Society Clinical Practice Guideline. Journal of Clinical Endocrinology and Metabolism, 2018. https://doi.org/10.1210/jc.2018-00229
- American Urological Association. Evaluation and Management of Testosterone Deficiency guideline. https://www.auanet.org/guidelines-and-quality/guidelines/testosterone-deficiency-guideline
- Lokeshwar SD et al. Decline in Serum Testosterone Levels Among Adolescent and Young Adult Men in the USA. European Urology Focus, 2021. https://doi.org/10.1016/j.euf.2020.02.006
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