Gestonorone caproate, also known as gestronol hexanoate or norhydroxyprogesterone caproate and sold under the brand names Depostat and Primostat, is a progestin medication which is used in the treatment of enlarged prostate and cancer of the endometrium. It is given by injection into muscle typically once a week. Side effects of gestonorone caproate include worsened glucose tolerance, decreased libido in men, and injection site reactions. Gestonorone caproate is a progestin, or a synthetic progestogen, and hence is an agonist of the progesterone receptor, the biological target of progestogens like progesterone. It has no other important hormonal activity. Gestonorone caproate was discovered in 1960 and was introduced for medical use by 1973. It has been used widely throughout Europe, including in the United Kingdom, and has also been marketed in certain other countries such as Japan, China, and Mexico. However, it has since mostly been discontinued, and it remains available today only in a handful of countries, including the Czech Republic, Japan, Mexico, and Russia. (en)