Reference Range for Progesterone in Adult Males
The reference range for progesterone in adult males is approximately 0.2-1.4 ng/mL (0.6-4.5 nmol/L), with most healthy men maintaining levels below 1.0 ng/mL.
Evidence-Based Normal Values
Research demonstrates that progesterone levels in healthy adult men are essentially equivalent to those in women during the follicular phase of the menstrual cycle 1. In a controlled study of healthy nonsmoking men, serum progesterone levels averaged 18.1 ± 3.1 ng/dL (approximately 0.57 nmol/L or 0.18 ng/mL), which did not differ significantly from follicular-phase women at 21.4 ± 5.4 ng/dL 1.
Additional research confirms that there are no great quantitative differences in progesterone secretion and serum levels between men and women outside the luteal phase 2. A prospective cohort study of 1,026 men with and without cardiovascular disease found no age-dependent changes in serum progesterone concentrations 2.
Clinical Context and Physiological Role
While progesterone is often considered a "female hormone," it serves important functions in men including:
- Spermiogenesis and sperm capacitation/acrosome reaction 2
- Testosterone biosynthesis in Leydig cells 2
- Central nervous system effects mediated primarily through 5α-reduced metabolites (neurosteroids), including modulation of gonadotropin secretion and sleep 2
- Effects on immune system, cardiovascular system, kidney function, and respiratory system 2
Laboratory Considerations
Most U.S. clinical laboratories report male progesterone reference ranges between 0.2-1.4 ng/mL (0.6-4.5 nmol/L), though the exact range may vary slightly between laboratories based on their specific assay methodology and population studied 1, 2.
It is important to note that progesterone levels in men remain relatively stable throughout the day and do not show the cyclical variations seen in premenopausal women 1. Blood samples drawn at 20-minute intervals between 6:00 and 9:00 AM showed consistent values, suggesting minimal diurnal variation 1.
Common Pitfalls
- Do not assume elevated progesterone in men is always pathological: Levels may transiently increase with certain medications or stress, but baseline values should remain in the reference range 2
- Smoking affects progesterone levels: Studies specifically excluded smokers when establishing reference ranges, as tobacco use has pronounced effects on serum progesterone 1
- Laboratory method matters: Ensure the laboratory uses validated assays with appropriate male reference ranges, as some older methods were optimized primarily for female reproductive ranges 1