Trenbolone acetate (TBA), an androgenic/anabolic steroid (AA), is a potent agonist of androgen receptors and has been extensively used as a growth promoter. TBA is a progestin and does not convert to estrogens. The effects of TBA are increased weight gain, improved food conversion efficiency, decreased muscle RNA and DNA concentrations, and decreased free cathepsin D activity in muscle. The half-life of trenbolone acetate in circulation is one day.