Metribolone (also known as Methyltrienolone or R1881) is a synthetic androgenic-anabolic steroid (AAS) derived from nandrolone. It is one of the most powerful AAS ever synthesized and is primarily used for research purposes Metribolone is known for its high potency and strong binding affinity to the androgen receptor in muscle tissue. Similar to other AAS, it can enhance muscle growth and strength, as well as improve athletic performance.