What is a "normal" testosterone level for a man over 40?

Total testosterone in men over 40 follows a progressive decline of approximately 1–2% per year after age 30, with the clinical reference range of 300–1,000 ng/dL representing a population distribution rather than an ideal range, most men over 40 with symptoms of hypogonadism that improve on testosterone therapy have baseline levels below 400 ng/dL, while the 300 ng/dL threshold for diagnosing hypogonadism captures the most severe cases but leaves many symptomatic men with "normal" levels undertreated (Bhasin et al., J Clin Endocrinol Metab, 2010).

The reference range problem in testosterone: laboratory "normal" ranges are set from the population distribution including sedentary, overweight, chronically stressed, sleep-deprived men, the average 50-year-old American man. This population average is not the best value. A man with a testosterone of 350 ng/dL and symptoms (low libido, poor sleep, declining muscle mass, fatigue, cognitive fog) may be below his personal right even though 350 ng/dL is "within range." The clinical evaluation of testosterone should consider both the laboratory value and the symptom burden, not the laboratory value in isolation.

Honesty Scale: Solid (1) for the 300 ng/dL hypogonadism threshold as the clinical standard. Promising (2) for the argument that symptomatic men with levels 300–400 ng/dL deserve clinical attention.

What to do: Test testosterone twice in the morning (7–9 AM, when testosterone peaks) with at least 1 week between tests, and include SHBG and albumin in the panel so free testosterone can be calculated. Total testosterone alone can be misleading in men with elevated SHBG (which binds testosterone out of biological activity).

For the full picture, read The Testosterone/TRT Deep Dive