Overview
What the Diagnosis Means
Male hypogonadism is a clinical syndrome, not a laboratory label.
Male hypogonadism is a clinical syndrome, not a laboratory label. The diagnosis requires compatible signs or symptoms together with consistently low serum testosterone. A single low result may reflect timing, acute illness, assay variation, or altered sex hormone-binding globulin (SHBG); symptoms alone may arise from depression, sleep deprivation, obesity, medication effects, chronic disease, or relationship and sexual-health concerns. The hypothalamus releases gonadotropin-releasing hormone, which stimulates pituitary luteinizing hormone (LH) and follicle-stimulating hormone (FSH). LH stimulates testicular Leydig cells to produce testosterone. FSH, together with intratesticular testosterone, supports Sertoli-cell function and sperm production. Testosterone therefore affects sexual function, erythropoiesis, muscle and bone health, energy, and mood, while the same gonadal axis is also central to fertility. The physiological pattern helps locate the failure: - Primary hypogonadism originates in the testes. Testosterone is low, while LH and FSH rise because the pituitary is trying to stimulate an underperforming gonad. - Secondary or central hypogonadism originates in the hypothalamus or pituitary. Testosterone is low, but LH and FSH are low or inappropriately normal; they are not responding adequately to the low testosterone signal....