Progestogen

Progestagens (also spelled progestogens or gestagens) are hormones which produce effects similar to progesterone, the only natural progestagen. All other progestogens are synthetic and are often referred to as progestins.

All progestagens have antiestrogenic (counteracting the effects of estrogens on the body) and antigonadotropic (inhibiting the production of sex steroids by gonads) properties.

Progestogens differ in their potency (affinity for progesterone receptors) and side effects. Such side effects may be androgenic (medroxyprogesterone and most C19 progestagens), antiandrogenic (cyproterone acetate), estrogenic, glucocorticoid (some C21 progestogens) or antimineralocorticoid (progesterone).

Birth control

 * Most progestogens are used for their antiestrogenic properties in combined (including estrogen) methods of hormonal contraception to avoid overstimulation of the endometrium which could lead to endometriosis and cancer.
 * Medroxyprogesterone acetate (brand name Depo Provera) is used by depot injection.
 * Etonogestrol is released by subcutaneous implants (Implanon). Similar products (Norplant and Jadelle contain Levonorgestrel.

Antiandrogen
Cyproterone is an antiandrogen.

Progestogen withdrawal bleeding
In a normal menstrual cycle, a sudden drop in progesterone levels triggers menstruation. Norethindrone acetate (brand name Aygestin) and medroxyprogesterone acetate (brand name Provera) may be used to artificially induce progestogen withdrawal bleeding.