ACE-083 — 1 mg

ACE-083 is a recombinant, dimeric fusion protein based on a modified human follistatin segment linked to a human IgG2 Fc domain. Unlike ACE-031’s receptor-based trap, ACE-083 uses follistatin-derived binding properties to capture muscle-growth-inhibitory ligands, particularly myostatin and activins. Its design emphasizes retention within treated muscle tissue rather than sustained systemic activity. The original laboratory and animal paper describes strong extracellular-matrix affinity and localized muscle enlargement, with functional improvement in selected neuromuscular-disease models. [1]

Human research examined whether those changes in muscle size would translate into useful strength and function. In the randomized phase 2 facioscapulohumeral muscular dystrophy study, investigators reported increased total and contractile muscle volume but no consistent improvements in functional or patient-reported outcomes. The publication states that the FSHD development program was discontinued. [2] A separate Charcot-Marie-Tooth study likewise reported larger muscle volume without broader motor-function or quality-of-life improvement, despite a signal in one strength measure. [3] These findings explain both the localized-muscle-growth description and the distinction between muscle enlargement and functional recovery. No matching current Umbrella Labs ACE-083 listing was established; the biological description does not verify the identity of a separately offered product.