A clinical trial of injectable testosterone undecanoate as a potential male contraceptive in normal Chinese men

This is a pilot dose-finding study of spermatogenic suppression using testo sterone undecanoate (TU) injections alone in normal Chinese men. Thirty-two healthy men were recruited. Volunteers underwent pretreatment evaluation, then a treatment period in which group I (n = 13) received 500 mg TU, group II (n = 12) received 1000 mg TU, and group III (n = 7) received placebo, r espectively, at monthly intervals during the treatment period (or until azo ospermia was achieved). Thereafter, they underwent a recovery period until all parameters returned to pretreatment levels. Eleven of 12 volunteers in the 500-mg TU group, and all volunteers in the 1000-mg TU group became azoo spermic. Faster suppression of spermatogenesis was achieved in the 1000-mg TU group. Serum testosterone increased significantly in the higher dose gro up at weeks 8 and 12, but remained within the normal range. Mean serum LH a nd FSH were profoundly suppressed by both doses to undetectable levels at w eek 16. TU injections did not cause a significant change in high density li poprotein cholesterol levels. No serious side-effects were found. We conclu de that both dosages of TU can effectively, safely, and reversibly suppress spermatogenesis in normal Chinese men.