ACE-031 is an investigational soluble activin type IIB receptor-Fc fusion protein designed to trap myostatin and related ligands. Its Duchenne muscular dystrophy programme was stopped for vascular adverse effects, and it has never been approved.

Limited evidence. Review the research and limitations before relying on this record.

ACE-031 combines the extracellular ligand-binding domain of activin receptor type IIB with an IgG1 Fc domain. It acts as a circulating decoy receptor for myostatin, activins and related TGF-beta-family ligands, preventing signalling through native ActRIIB receptors and reducing SMAD2/3-mediated restraint of skeletal-muscle growth. Its broad ligand capture is also why effects are not confined to muscle.

A 48-person single-ascending-dose study reported dose-proportional exposure and a mean half-life of 10 to 15 days. The Fc fusion supplies the long exposure. Those data describe the sponsor-manufactured clinical material after one dose and cannot establish the identity or pharmacokinetics of products sold under the same name online.

No published, curated interaction record is available for this compound in the current library.

A single-dose placebo-controlled study in 48 healthy postmenopausal women reported increases in lean mass and thigh-muscle volume at the highest tested exposure. A later randomised placebo-controlled Duchenne muscular dystrophy study enrolled only 24 participants and was stopped after the second regimen; six-minute-walk and body-composition signals were trends rather than statistically significant efficacy. No confirmatory programme or approval followed.

The Duchenne trial stopped because of epistaxis and telangiectasias, consistent with trapping ligands outside the myostatin pathway. A 2025 laboratory survey of 14 black-market products found that most contained an ActRIIB-reactive protein but not full-length ACE-031 and also contained multiple other proteins, so product identity is a separate and documented hazard. No regulator has approved this substance for the use described here, so there is no label-verified dose, purity standard, or safety monitoring requirement behind it.

This is a source-backed summary, not a recommendation. Read the mechanism, pharmacokinetic, human-evidence and reported-effect fields separately: a mechanism is not an outcome. Availability, legal status and product quality differ by jurisdiction; consult a qualified clinician.