Research

Hormonal

In healthy aging men, serum total testosterone and free testosterone index decline at a constant, age-invariant rate regardless of chronic illness, medication use, or lifestyle factors, leading to a high prevalence of hypogonadal levels in older age.

If you are an older man, expect your testosterone to drop by about 3.2 ng/dL every year, regardless of how healthy you are. This is a biological fact, not just a result of being sick. By your 70s or 80s, a significant portion of men will have testosterone levels in the 'hypogonadal' range. If you experience symptoms like loss of muscle mass, low energy, or sexual dysfunction, discuss testing with your doctor, as replacement therapy may be beneficial for those with the lowest levels.

StrongSupportsVERY_HIGH confidence
Our observations of health factor independent, age-related longitudinal decreases in T and free T, resulting in a high frequency of hypogonadal values, suggest that further investigation of T replacement in aged men... are justified.
S. Mitchell Harman et al. · The Journal of Clinical Endocrinology & Metabolism · 2001

Why this rating

Large longitudinal sample (n=890), long follow-up, rigorous statistical modeling (mixed-effects), and control for secular/storage artifacts.

Source

Longitudinal Effects of Aging on Serum Total and Free Testosterone Levels in Healthy Men

S. Mitchell Harman et al. · The Journal of Clinical Endocrinology & Metabolism · 2001

DOI 10.1210/jcem.86.2.7219

cohort · n=890Cited 2,679×
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DOI resolved against Crossref · corpus check 2026-06-10

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