ACE-031

• Historical studies reported exploratory body-composition, muscle-volume, muscle-force and biomarker signals, but no approved benefit was established and the development program was discontinued

CAS

1169766-01-1

Formula

C₃₄₁₈H₅₁₈₈N₉₂₈O₁₀₆₂S₃₈ (homodimeric glycoprotein; per KEGG DRUG D₁₀₃₄₇)

Molecular weight

77489.89 Da

Appearance

White to off-white lyophilized powder; should reconstitute into a clear solution with no visible turbidity or precipitate

Purity

≥ 99.0% · target, verify batch COA

Storage

Store the supplied batch according to its COA and formulation-specific stability study. Generic vendor statements such as 2-8 degrees Celsius, minus 20 degrees Celsius for long-term storage or a fixed post-reconstitution period are not interchangeable across an Fc-fusion biologic, salt/buffer systems and container formats. Record excursions and avoid unvalidated freeze-thaw cycles.

MOQ

1 kit (10 vials) per SKU

Lead time

21–45 days

ACE-031 (ramatercept; YY-125) is an investigational recombinant homodimeric fusion protein comprising the extracellular ligand-binding domain of human ActRIIB/ACVR2B linked to a human IgG1 Fc region. It functions as a soluble ligand trap for several TGF-beta-family ligands, including myostatin, GDF-11 and activins. It was studied in Phase 1 and Phase 2 programs, including Duchenne muscular dystrophy, but the DMD study was stopped after vascular adverse events including epistaxis and telangiectasia; the development program was later discontinued. ACE-031 has no approved indication. Current use is limited to controlled research, reference and anti-doping contexts, and an RUO lot is not interchangeable with the historical clinical-trial material.

• Historical research included Duchenne muscular dystrophy and single-dose body-composition studies, but the DMD trial stopped after the second regimen because of epistaxis and telangiectasias, efficacy differences were not statistically significant, and development was permanently discontinued
• More recent marmoset work remains preclinical
• ACE-031 is explicitly included among decoy activin receptors prohibited at all times under WADA category S4.3; anti-doping status must be read from the current official list and applicable TUE rules, not from vendor summaries.

ACE-031 uses the ActRIIB extracellular domain to bind multiple circulating TGF-beta-family ligands and reduce their access to native activin type II receptors, thereby decreasing downstream Smad2/3 signaling. This broad ligand-trap design differs from a myostatin-selective antibody and from bimagrumab, which blocks ActRIIA/ActRIIB receptors. The DMD trial documented epistaxis and telangiectasia. Broad capture of ligands involved in vascular homeostasis, including BMP9/10, has been proposed as a mechanistic explanation, but the trial did not establish the causal contribution of each ligand. The vascular safety signal and discontinued status are part of the mechanism interpretation, not optional context.

• ACE-031 is an unapproved, discontinued investigational biologic and is not for human use
• In the DMD Phase 2 report, epistaxis and telangiectasias led to early study termination; gingival bleeding was also reported in program summaries
• Its broad ligand trap may affect BMP-9/BMP-10 signaling and provides a biologically plausible explanation for vascular findings, but this mechanism should not be presented as definitive proof for every event
• A 2025 peer-reviewed analysis found major identity and impurity problems in products sold as ACE-031
• Laboratory work requires an institutional risk assessment, batch-specific safety documentation and controls appropriate to an unverified recombinant protein
• WADA S4.3 status is a separate anti-doping restriction and does not establish pharmaceutical quality or safety.

Interactions reported in the literature

• As an RUO substance, no formal human co-administration protocol exists
• Mechanistically, there is a theoretical possibility of additive inhibition of the same signaling pathway when combined with other myostatin-pathway inhibitors (e.g., YK-11, Follistatin-344), but no safety data support this
• Because of its broad TGF-beta superfamily ligand-binding profile (including BMP-9/10), combining it with substances that affect coagulation or vascular integrity warrants particular caution — this is consistent with, and not contradictory to, the vascular-related adverse-effect mechanism described in the safety section.

Laboratory: Manufacturer's QC laboratoryTests: HPLC purity · MS identity · endotoxin · fill amount

• 1 mg

Previews are blurred on purpose so the documents cannot be reused; third-party reports show their first page only. Sales sends the clear full version for the product and strength you ask about.

Independent test fails? Full refund.

On every batch COA: HPLC purity · MS identity · endotoxin · fill amount · Verify LyoPep

Ask for the current packet, not a generic certificate

• Visual appearance cannot establish identity, purity, folding, glycosylation or biological activity
• Procurement qualification should define ACE-031 as the disulfide-linked ACVR2B extracellular-domain-IgG1 Fc fusion homodimer and require traceable expression and purification records, intact and reduced mass characterization, peptide mapping or orthogonal sequence confirmation, identity-selective immunoblotting, aggregate and fragment analysis, purity with method and chromatograms, protein content, host-cell protein and DNA controls, endotoxin, bioburden or sterility where claimed, and formulation/stability data
• The 2025 study of 14 black-market products found that only 12 were ACVR2B-immunoreactive and those contained full-length human ACVR2B rather than authentic ACVR2B-Fc ACE-031, with additional protein impurities
• A plausible band or clear solution alone is therefore insufficient.

Store the supplied batch according to its COA and formulation-specific stability study. Generic vendor statements such as 2-8 degrees Celsius, minus 20 degrees Celsius for long-term storage or a fixed post-reconstitution period are not interchangeable across an Fc-fusion biologic, salt/buffer systems and container formats. Record excursions and avoid unvalidated freeze-thaw cycles.

State the destination and timing so receipt can be planned, then move the material into its stated storage condition on arrival.

• The evidence base should be read in layers. Attie et al. 2013, PMID 23169607, is a small first-in-human single-dose study and establishes pharmacokinetic and body-composition signals, not approval. Campbell et al. 2017, PMID 27462804, reports the stopped randomized DMD trial, vascular adverse events and non-significant efficacy trends. Lee 2021, PMID 33938454, provides pathway and development context. Reichel et al. 2025, PMID 40312924, directly demonstrates the authenticity risk of black-market products. KEGG D10347 and NCATS UNII 42HQC6QLEK support standardized identity, and the current WADA Prohibited List governs anti-doping status. Patient-advocacy announcements are useful for chronology but do not replace trial reports or regulatory records.

1. 01

   Myostatin inhibitor ACE-031 treatment of ambulatory boys with Duchenne muscular dystrophy: Results of a randomized, placebo-controlled clinical trial

   Muscle & Nerve · 2017 · peer-reviewed original research (randomized, placebo-controlled Phase 2 clinical trial report)

   Open source
2. 02

   A single ascending-dose study of muscle regulator ACE-031 in healthy volunteers

   Muscle & Nerve · 2013 · peer-reviewed original research (Phase 1 randomized, double-blind, placebo-controlled dose-escalation trial)

   Open source
3. 03

   Targeting the myostatin signaling pathway to treat muscle loss and metabolic dysfunction

   The Journal of Clinical Investigation · 2021 · peer-reviewed review article

   Open source
4. 04

   Gel electrophoretic detection of black market ACE-031

   Drug Testing and Analysis · 2025 · peer-reviewed original research, WADA-funded anti-doping analytical study

   Open source
5. 05

   Administration study of black market ACE-031 (Ramatercept)

   World Anti-Doping Agency (WADA) — Scientific Research resource page · 2025 · regulatory/anti-doping body resource page (WADA-funded research summary)

   Open source
6. 06

   UPDATE: ACE-031 Clinical Trials in Duchenne MD

   Quest Magazine, Muscular Dystrophy Association (MDA) · 2013 · patient advocacy organization publication (news/update article)

   Open source
7. 07

   Acceleron awarded $1.5 million grant from Muscular Dystrophy Association to support ACE-031

   Muscular Dystrophy Association (MDA), distributed via EurekAlert! · 2011 · patient advocacy organization press release

   Open source
8. 08

   ACE-031 Study Terminated: What Does This Mean?

   Parent Project Muscular Dystrophy (PPMD) Community Blog · 2011 · patient advocacy organization community blog post

   Open source

• How to read a peptide COA without confusing purity, identity and content
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