Testosterone is used in medicine in substitution therapy when there are insufficiencies in the functioning of sex glands in men. It is also used for climacteric disorders in women and for certain types of tumors. Intake of testosterone over prolonged periods blocks the secretion of gonadotrophic hormones and suppresses sexual activity. In the pharmaceutical industry, the hormone is obtained from sterols and steroid saponins. Highly active synthetic analogues of testosterone, such as testosterone propionate and methyltestosterone, are used in medical practice.