[4] Side effects of gestonorone caproate include worsened glucose tolerance, decreased libido in men, and injection site reactions.

[1][16][17][18] 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.

[5] Side effects of gestonorone caproate have been reported to include worsened glucose tolerance, decreased libido in men, and local injection site reactions such as irritation.

[5] Gestonorone caproate is a potent, long-acting, and pure progestogen,[9][10][13] possessing no androgenic, anabolic, antiandrogenic, estrogenic, antiestrogenic, glucocorticoid, mineralocorticoid, or teratogenic effects.

[5][11][12][13][21] It is approximately 20 to 25 times more potent than progesterone or hydroxyprogesterone caproate in animal bioassays when all are given by subcutaneous injection.

[31][32][33][29][30] In accordance with its lack of glucocorticoid activity, gestonorone caproate has no anticorticotropic effects, and does not influence the secretion of adrenocorticotropic hormone.

[6] Gestonorone caproate has been found to decrease the weights of the prostate gland and seminal vesicles by 40 to 70% in adult male rats.

[5] A single intramuscular injection of 25 to 50 mg gestonorone caproate in oil solution has been found to have a duration of action of 8 to 13 days in terms of clinical biological effect in the uterus in women.

[6] Following an intramuscular injection of 300 mg gestonorone caproate, only a slight increase in urinary pregnanetriol excretion has been observed.

[63][16][17][18][19] Gestonorone caproate has been available widely in Europe, including in the United Kingdom, and has also been marketed in Japan, China, Mexico, and certain other countries.

[1][16][17][18] However, it has been discontinued in most countries and its availability is more limited today; it appears to remain marketed only in the Czech Republic, Japan, Mexico, and Russia.

[71] Gestonorone caproate was studied by Schering for use as a progestogen-only injectable contraceptive across a dose range of 2.5 to 200 mg once every one or two months but was never marketed.

[61] Gestonorone caproate has been studied in the treatment of ovarian cancer (in combination with cyclophosphamide),[5][22][79][80] menstrual cycle-related mouth ulcers,[21] and as a component of menopausal hormone therapy.