In Detail
Testosterone production declines gradually with age — roughly 1% per year after about 30 — but the rate and clinical impact vary widely between men. A combination of factors usually drives a symptomatic deficiency.
Common contributors include obesity (adipose tissue converts testosterone to estrogen via aromatase), poor sleep and untreated sleep apnea, chronic stress with elevated cortisol, insulin resistance and metabolic syndrome, certain medications (opioids, glucocorticoids, some antidepressants), prior anabolic steroid use, head trauma, and chronic illnesses such as kidney or liver disease.
Identifying the underlying contributors matters because some are reversible. Treating sleep apnea, losing fat mass, addressing medications, and managing stress can meaningfully raise testosterone in some men without exogenous therapy. When optimization alone is insufficient, medically supervised testosterone therapy is appropriate.