Metribolone 2000 is an AAS, or an agonist of the AR, with both anabolic and androgenic activity. It is one of the most potent AAS to have ever been synthesized, with 120 to 300 times the oral anabolic potency and 60 to 70 times the androgenic potency of the reference AAS methyltestosterone in castrated male rats, although the same level of potency has not been observed in studies in humans. In addition to the AR, metribolone has high affinity for the progesterone receptor (PR), and binds to the glucocorticoid receptor (GR) as well.
Metribolone is a relative of Trenbolone family, but unlike them it is much more powerful, and like Trenbolones is a progestine. Minimal doses and maximum result shown by muscle definition and volume are Metribolone features.