Equipoise is the popularly referenced brand name for the veterinary injectable steroid boldenone undecylenate. Specifically it is a derivative of testosterone, which exhibits strong anabolic and moderately androgenic properties. The equipoise undecylenate ester greatly extends the activity of the drug (the undecylenate ester is only one carbon atom longer than decanoate), so that clinically injections would need to be repeated every three or four weeks.