● pepmg Research Desk · Peer-reviewed evidence review
What the research says about ACE-031
A neutral review of ACE-031 (ramatercept), an investigational ActRIIB-Fc fusion protein with human trial data and important safety limitations. Research use only.
Moderate evidence — Limited human trials — often early-phase. This describes the state of the published literature, not a claim that this compound works, is safe, or is for human use. Research use only.
The short version
- ACE-031 is a soluble activin type-IIB receptor fused to an IgG1 Fc domain; it binds myostatin and other ligands involved in regulation of muscle mass [1][2].
- Two randomized human studies are available, but they do not establish an approved use. The Duchenne muscular dystrophy study stopped early after potential safety concerns involving epistaxis and telangiectasias [2].
- A 2025 analysis of products sold as black-market ACE-031 found that not every tested product contained an ActRIIB-immunoreactive protein [3]. Research use only.
What ACE-031 is
ACE-031, also called ramatercept, is a fusion protein containing the extracellular portion of activin receptor type IIB and an IgG1 Fc region. It was developed to sequester myostatin and related ligands rather than act as a conventional short peptide [1][2].
It remains investigational. Listings from research vendors should not be treated as approved pharmaceutical products.
What human trials measured
Moderate evidenceA randomized, double-blind, placebo-controlled single-dose study enrolled 48 healthy postmenopausal women and measured safety, pharmacokinetics, body composition, and biomarkers [1]. The findings belong to that limited single-dose study and do not establish general safety or clinical benefit.
A randomized ascending-dose study in boys with Duchenne muscular dystrophy primarily evaluated safety and pharmacology. The trial reported non-significant functional trends and was stopped after the second regimen because of potential safety concerns including nosebleeds and telangiectasias [2].
Identity and evidence limitations
A 2025 analytical study examined 14 products marketed as black-market ACE-031 and reported that 12 contained an ActRIIB-immunoreactive protein [3]. That result does not authenticate any listing tracked by pepmg, but it directly illustrates identity uncertainty in this market.
Human trials justify a moderate evidence label for characterization of the investigational molecule, not a claim that vendor material is effective or safe. No dosing recommendation is provided.
Evidence boundary
What this research cannot tell us
- The clinical program was limited, and the Duchenne muscular dystrophy trial stopped early because of potential safety concerns [2].
- The trials studied sponsor-manufactured investigational material and therefore cannot establish the identity of products sold by current vendors [1][2].
- The black-market testing paper sampled other products and does not authenticate any specific vendor or listing tracked by pepmg [3].
Sources · 3
pepmg summarizes the peer-reviewed literature and links to every source — it sells nothing, ships nothing, and gives no medical or human-use guidance. Don't just trust this summary: follow any citation to its source and read it yourself. Research use only.