What is the normal total serum testosterone concentration for a healthy 52‑year‑old male?

Normal Testosterone Levels for a 52-Year-Old Male

For a healthy 52-year-old male, normal total serum testosterone ranges from approximately 264 to 916 ng/dL, with a mean value around 500-600 ng/dL. 1, 2

Age-Specific Reference Ranges

The most robust harmonized reference data from four major cohort studies (Framingham Heart Study, European Male Aging Study, Osteoporotic Fractures in Men Study, and Male Sibling Study of Osteoporosis) established the following percentile values for healthy, non-obese men aged 19-39 years 2:

• 2.5th percentile: 264 ng/dL
• 5th percentile: 303 ng/dL
• 50th percentile (median): 531 ng/dL
• 95th percentile: 852 ng/dL
• 97.5th percentile: 916 ng/dL

For men over 40 years (including your 52-year-old patient), the mean testosterone level is approximately 13.0 nmol/L (375 ng/dL), with a 2.5-97.5 percentile range of 6.6-25.3 nmol/L (190-730 ng/dL). 3 Importantly, research demonstrates that mean testosterone does not decline further after age 40, though variance increases significantly—meaning some men maintain high levels while others drop lower. 3

Clinical Diagnostic Thresholds

The AUA defines testosterone below 300 ng/dL as the diagnostic threshold for low testosterone across all adult age groups, requiring confirmation with two separate early morning measurements (8-10 AM). 1, 4

The clinical interpretation framework is 4:

• <230 ng/dL: Usually warrants testosterone replacement in symptomatic men
• 231-346 ng/dL: Gray zone—consider 4-6 month trial in symptomatic patients after risk-benefit discussion
• >350 ng/dL: Typically does not require replacement therapy

Critical Measurement Considerations

Morning timing is mandatory. Testosterone exhibits marked diurnal variation with peak levels occurring between 8-10 AM. 1, 4 Measurements taken later in the day risk false-positive diagnoses of hypogonadism. 4

Two separate measurements are required because of significant intra-individual variability and assay differences. 1 Single measurements are insufficient for diagnosis. 1

In men with obesity or borderline values (near 300 ng/dL), free testosterone by equilibrium dialysis and SHBG must be measured. 4 Obesity lowers SHBG, which can artificially reduce total testosterone while free testosterone remains normal—this represents functional rather than true hypogonadism. 4

Laboratory Variability: A Critical Pitfall

Reference ranges vary dramatically across laboratories, with lower limits ranging from 130 to 450 ng/dL (a 350% difference) and upper limits from 486 to 1,593 ng/dL (a 325% difference). 5, 6 This massive variation stems from:

• Different assay methodologies (8 different assays for total testosterone) 6
• Reference populations of unknown medical/reproductive health 5
• Only 9% of laboratories create region-specific reference ranges 5

This variability directly affects clinical decision-making and explains why up to 25% of men receiving testosterone therapy do not actually meet diagnostic criteria for hypogonadism. 1, 5

Practical Algorithm for Your 52-Year-Old Patient

1. Obtain two fasting morning total testosterone measurements (8-10 AM) on separate days 1, 4

2. If both values are <300 ng/dL: Proceed with hypogonadism workup (measure LH, FSH, free testosterone by equilibrium dialysis, SHBG) 1, 4

3. If values are 231-346 ng/dL: Measure free testosterone and SHBG; consider symptoms carefully before treatment 4

4. If values are >350 ng/dL: Testosterone replacement is not indicated regardless of symptoms 4

5. For obese patients or borderline values: Always measure free testosterone by equilibrium dialysis and SHBG to distinguish true from functional hypogonadism 4

The key pitfall to avoid: Never diagnose hypogonadism on a single measurement, never test outside morning hours, and never ignore the need for free testosterone assessment in borderline or obese patients. 1, 4