Metenolone enanthate, or methenolone enanthate, sold under the brand names Primobolan Depot and Nibal Injection, is an androgen and anabolic steroid (AAS) medication which is used mainly in the treatment of anemia due to bone marrow failure.[2][3][4][5][6][7] It is given by injection into muscle.[6] Although it was widely used in the past, the drug has mostly been discontinued and hence is now mostly only available on the black market. [5][6][3] A related drug, metenolone acetate, is taken by mouth.[6]

Side effects of metenolone enanthate include symptoms of masculinization like acne, increased hair growth, voice changes, and increased sexual desire.[6] The drug is a synthetic androgen and anabolic steroid and hence is an agonist of the androgen receptor (AR), the biological target of androgens like testosterone and dihydrotestosterone (DHT).[6][8] It has moderate anabolic effects and weak androgenic effects, as well as no estrogenic effects or risk of liver damage.[6][8] Metenolone enanthate is a metenolone ester and a long-lasting prodrug of metenolone in the body.[6]

Metenolone enanthate was introduced for medical use in 1962.[6] In addition to its medical use, metenolone enanthate is used to improve physique and performance.[6] The drug is a controlled substance in many countries and so non-medical use is generally illicit.[6] It remains marketed for medical use only in a few countries, such as Spain and Turkey.[5][6]