Common causes for reduced testosterone production includes:

Testicular Disorders

• Klinefelter's syndrome
• Cryptorchidism and defects of testis development (Twisted or strangulated testes)
• Orchitis (Inflammation of the testes resulting in permanent damage)
• Orchidectomy (surgical removal of the testes)
• Toxin exposure (radiation, chemotherapy or radiotherapy, domestic, industrial or environmental poisons)

Brain Disorders (Hypothalamic-Pituitary Dysregulation)

• Kallmann's syndrome (a genetic disorder)
• Other genetic causes
• Pituitary gland tumor and treatment (surgery and/or irradiation)
• Haemochromatosis (Blood iron disorder)
• Craniopharyngioma (benign tumor of the brain)

External Factors

• Acute critical illness, burns, major trauma or surgery
• Drug use (eg, opiates, glucocorticoids, anabolic steroids)
• Chronic disease and its treatment
• Alcohol abuse
• Smoking
• Ageing

Recommended next page - Treatment of Testosterone Deficiency in Men