Profile: United Peptides is a manufacturer of peptides. We specialize in the sales and distribution of peptides to research organizations, academic institutions as well as individual researchers. ACE-031 is an engineered decoy receptor used in attempts to treat children with Duchenne Muscular Dystrophy (DMD). The ACE-031 receptor circulates outside the muscle-fiber membrane. Because this receptor binds to myostatin, it lowers the amount of myostatin that can bind to the native receptor in the membrane.