Treatment of idiopathic testicular failure with high-dose testosterone undecanoate: a double-blind pilot study

The effect of high-dose (240 mg/d) intake of testosterone (T) undecanoate was studied for sperm characteristics, function of the accessory sex glands, and hormonal parameters of men with idiopathic oligozoospermia, asthenozoospermia, or teratozoospermia using a two-phase protocol including a 3-month double-blind period followed by a 3-month open phase. Increased sperm viability and semen content of adenosine triphosphate were either not reproducible after patients on placebo were switched over to T undecanoate or did not reach statistical significance, whereas no changes were detected in other sperm characteristics and the accessory sex glands. Intake of T undecanoate significantly increased the concentration of 5-alpha-dihydrotestosterone (DHT) and the ratio of DHT over T in peripheral blood, suppressed the luteinizing hormone concentration, and tended to decrease serum follicle-stimulating hormone concentration. It is concluded that high-dose T undecanoate is not effective in the treatment of men with infertility with idiopathic testicular failure.