Testosterone/progestin regimens: a realistic option for male contraception?

Exogenously administered testosterone functions as a contraceptive in the male by suppressing the secretion of luteinizing hormone (LH) and follicle-stimulating hormone (FSH) from the pituitary. After 2 to 3 months of treatment, low levels of FSH and LH lead to markedly decreased sperm concentrations. This approach to contraceptive development appears safe and fully reversible, however, sperm concentrations are not suppressed to zero in all men. Therefore, researchers have combined testosterone with progestins to further suppress pituitary gonadotropins and optimize contraceptive efficacy. Current testosterone/progestin combinations using newer, long-acting forms of testosterone combined with the progestins such as desogestrel, etonorgestrel, norethisterone, medroxyprogesterone and levonorgestrel suppress spermatogenesis-to azoospermia without causing severe side effects in close to 90% of men. Significant suppression of spermatogenesis is observed in the remainder of individuals. These findings may soon result in the marketing of a safe, reversible and effective hormonal contraceptive for men.