Testosterone butyrate

Testosterone butyrate, or testosterone butanoate, also known as androst-4-en-17β-ol-3-one 17β-butanoate, is a synthetic, steroidal androgen and an androgen ester – specifically, the C17β butanoate ester of testosterone – which was first synthesized in the 1930s and was never marketed. Its ester side-chain length and duration of effect are intermediate between those of testosterone propionate and testosterone valerate.