ACE-031
Myostatin Inhibitor / Ligand TrapdiscontinuedAlso known as: ActRIIB-Fc, Activin Receptor Type IIB Decoy, ACVR2B-Fc
A soluble activin receptor type IIB fusion protein that acts as a myostatin trap, promoting significant muscle growth by intercepting growth-limiting signals before they reach muscle cells.
Overview
ACE-031 is a soluble form of the activin receptor type IIB (ActRIIB) fused to the Fc portion of human IgG1 antibody. It functions as a decoy receptor or 'ligand trap' that circulates in the bloodstream and binds myostatin, activin, GDF-11, and other TGF-beta superfamily ligands before they can reach their cellular receptors. By intercepting these growth-inhibiting signals, ACE-031 allows muscle tissue to grow beyond its normal limits. Originally developed by Acceleron Pharma for Duchenne muscular dystrophy (DMD), clinical trials were halted after Phase 2 due to off-target effects including epistaxis and telangiectasias (likely from inhibition of BMP-9/10 signaling in blood vessels). Despite the clinical setback, ACE-031 remains of high interest in the performance enhancement community for its potent muscle-building effects demonstrated in trials.
Mechanism of Action
ACE-031 acts as a circulating ligand trap: (1) Binds myostatin (GDF-8) in the bloodstream before it reaches ActRIIB on muscle cells; (2) Also traps activin A/B, GDF-11, and other growth-inhibitory TGF-beta ligands; (3) Prevents SMAD2/3 phosphorylation and downstream growth suppression; (4) Unleashes satellite cell differentiation and muscle fiber hypertrophy; (5) Fc fusion provides extended half-life of 2-3 weeks; (6) Off-target inhibition of BMP-9/10 affects vascular endothelial signaling, causing the epistaxis seen in trials.
Molecular Formula
Fusion protein (large molecule)
Molecular Weight
~90,000 g/mol
Sequence
ActRIIB extracellular domain fused to human IgG1 Fc region
Dosage Protocols
Dose Range
0.5 mg/kg – 3 mg/kg
Frequency
Every 2 weeks
Route
subcutaneous
Cycle Length
As studied in clinical trials
Based on Phase 2 DMD trial dosing. Clinical trials were discontinued. Not recommended for self-administration due to vascular side effects. Included for informational purposes only.
Source: Phase 2 clinical trial (Attie et al., 2013)
🧮 Personalized Dosage Calculator
💰 Estimated Pricing
Typical Supply
1mg vial
Last Updated
2026-02
Research-only compound (activin receptor decoy). Very limited availability. Development discontinued by Acceleron Pharma.
⚠️ Prices are estimates based on publicly available data and may vary significantly by vendor, location, and prescription status. This is not medical or financial advice.
Side Effects
| Effect | Severity |
|---|---|
| Epistaxis (nosebleeds) | moderate |
| Telangiectasia | moderate |
| Gum bleeding | moderate |
| Injection site reaction | mild |
Pros & Cons
Demonstrated significant lean muscle mass increases in human clinical trials
Long half-life (2-3 weeks) requiring only biweekly dosing
Traps multiple growth-inhibitory ligands beyond just myostatin
Clinical trials halted due to vascular side effects (nosebleeds, telangiectasia)
Off-target inhibition of BMP-9/10 causes dangerous vascular fragility
Not available through any legitimate source — products claiming to be ACE-031 are suspect
Complex fusion protein impossible to verify for quality without advanced analytics
Research Studies
🩸 Blood Work
No specific bloodwork requirements reported for this peptide. General health panels are always recommended before starting any peptide protocol.
Legal Status
Investigational drug — clinical trials halted. Not available through legitimate channels. Banned by WADA. Any products sold as ACE-031 are of uncertain authenticity.
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