Testicular atrophy is a medical condition in which the male reproductive organs (the testes, which in humans are located in the scrotum) diminish in size and may be accompanied by ceasing to function. This is not used to refer to temporary changes such as those brought on by cold. Some medications, including anabolic steroids, can cause testicular atrophy^[1] which will reverse when the course of treatment ends, provided it is not too long (in excess of 20 weeks).

Some additional causes of testicular atrophy can include atherosclerosis, cryptorchidism, insufficient luteinizing hormone production most frequently seen in the hypothyroid state, and vascular injury during inguinal hernia surgery, drug side effects (Oxymetholone).