Can 9ml Bilateral Testicles Produce Normal Testosterone Levels?
Yes, bilateral testicles of 9ml each can produce a testosterone level of 40 nmol/L (approximately 1,153 ng/dL), which is well within the normal physiologic range and actually represents a robust testosterone level for an adult male. 1
Understanding Normal Testosterone Ranges
The normal reference range for total testosterone in adult males is 300-800 ng/dL (10.4-27.7 nmol/L) in most laboratories 1. Your level of 40 nmol/L converts to approximately 1,153 ng/dL, which places you in the upper-normal to high-normal range 2.
- Harmonized reference ranges from four major cohort studies show that healthy nonobese men aged 19-39 years have testosterone levels ranging from 264-916 ng/dL (2.5th to 97.5th percentile) 2
- Your level of 40 nmol/L exceeds even the 97.5th percentile for healthy young men 2
- The American Urological Association defines testosterone below 300 ng/dL as the threshold supporting a diagnosis of low testosterone 3
Testicular Volume and Testosterone Production
While testicular volume can provide some indication of testicular function, 9ml bilateral testicles (18ml total) fall within the lower end of normal adult testicular volume, and your testosterone level demonstrates that these testicles are functioning robustly 4.
- Normal adult testicular volume ranges from approximately 15-25ml total 4
- Testosterone production capacity depends more on Leydig cell function than absolute testicular size 5
- Your testosterone level of 40 nmol/L clearly demonstrates adequate Leydig cell function regardless of testicular volume 1
Clinical Interpretation
You do not have hypogonadism or testosterone deficiency. In fact, your testosterone level is excellent 3, 1.
- Testosterone levels below 8 nmol/L highly support a diagnosis of hypogonadism, while levels greater than 12 nmol/L are considered normal 5
- Your level of 40 nmol/L is more than three times the upper threshold for normal 5
- The "grey zone" requiring further evaluation is between 8-12 nmol/L, which does not apply to your situation 5
Important Considerations
If you were concerned about fertility or testicular function due to the 9ml testicular size, your robust testosterone production suggests normal hypothalamic-pituitary-gonadal axis function 4.
- Morning testosterone measurements are most accurate, as levels naturally fluctuate throughout the day with peak levels in the morning 1
- If this measurement was not taken in the morning (8-10 AM), a confirmatory morning measurement would provide the most accurate assessment 3, 1
- Testosterone deficiency requires both low testosterone levels (typically <300 ng/dL or <10.4 nmol/L) AND specific symptoms such as diminished libido, erectile dysfunction, or decreased energy 3, 5
Your testosterone level of 40 nmol/L is entirely normal and indicates that your testicles, despite being 9ml each, are producing testosterone at a level that exceeds what most healthy adult males achieve.