[Action mechanism of synthetic androgens].

The most common androgen supplement used in Japan involves intramuscular injection of testosterone esters, such as, testosterone enanthate and testosterone propionate. As orally active androgens, derivatives of testosterone, such as, methyltestosterone and fluoxymesterone have also been used. These synthetic androgens have most commonly been used as replacement androgens in male patients with hypergonadotropic hypogonadism, as well as, hypogonadotrophic hypogonadism. The use in idiopathic male infertility and in elderly men with erectile dysfunction, however, has been shown to be less effective. Furthermore, relatively high doses of synthetic androgens are given in athletes to ensure success in sports and are used as hormonal methods for male contraception.