N-Butyl-4-androsten-3-one-17beta-carboxamide, with CAS number 131267-80-6, is a synthetic steroid derivative. Its structure is based on the androstane skeleton, featuring a 4-en-3-one moiety (characteristic of many anabolic steroids) and a 17beta-carboxamide group with an n-butyl substituent. This compound is primarily known as an active pharmaceutical ingredient (API) or a key advanced intermediate in the synthesis of selective androgen receptor modulators (SARMs) and other anabolic-androgenic steroids. It falls under the category of endocrine and metabolic drugs due to its intended action on the androgen receptor, which influences muscle growth, bone density, and other metabolic processes. It has been investigated in research contexts related to performance enhancement and the treatment of conditions like muscle wasting. As a structurally complex steroid derivative, it is not a common, general-purpose synthetic building block. Its primary identity and value are tied to its specific biological activity and role in pharmaceutical synthesis, placing it firmly within the medicinal chemistry domain.