ACE-031

Areas of active research — not promised effects

Each tag links to other compounds with research into that goal. Research use only: these are areas of study, not human-use claims.

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ACE-031 has no FDA approval and no active IND as of 2026. It held FDA Fast Track and Orphan Drug designations for DMD, but these lapsed when the program was discontinued in 2013. As a large recombinant fusion protein (>40 amino acids), it is regulated as a biologic under the PHSA; 503A pharmacy compounding of biologics is not permitted without a biologics license. The 2026 FDA/HHS Category-2 peptide reclassification (docket FDA-2025-N-6895, effective Apr 23 2026) applies to small peptides and did not include ACE-031, which was never on the 503A bulk drug substances list.

Confirmed high-severity market-integrity event (enforcement / recall / counterfeit)

Transparent blend · bci-1.0 · never paid-placement

Primary name

ACE-031

Length

512 aa

Origin

Engineered by Acceleron Pharma; constructed by fusing the extracellular ligand-binding domain of human activin receptor type IIB (ACVR2B) to the Fc region of human IgG1. Not derived from a natural peptide; the reference UniProt entry Q13705 represents the canonical ACVR2B precursor, not the engineered fusion construct.

Appearance

White to off-white lyophilized powder (vendor-reported; typical for IgG1-Fc fusion proteins)

Solubility

Soluble in aqueous buffers; typically formulated in isotonic saline or phosphate…

Sequence · one-letter

Stability: Sensitive to repeated freeze-thaw and elevated temperatures; Fc-fusion proteins are susceptible to aggregation. Stability data specific to ACE-031 RUO preparati

Vial sizes

1 mg

Purity grades

≥95% HPLC / ≥98% HPLC

Salt forms

Free base (primary)

• GHS hazard class on file
• PPE & spill response
• Disposal guidance
• Not-for-human-consumption posture

How much research exists, and of what maturity — never a verdict on whether it works.

Mechanism of action

• ACE-031 functions as a circulating decoy receptor that competitively sequesters multiple TGF-beta superfamily ligands — principally myostatin (GDF-8), activin A, and GDF-11 — before they can engage endogenous cell-surface ActRIIB on skeletal muscle
• By removing these negative regulators, downstream SMAD2/3 signaling is attenuated, relieving transcriptional suppression of muscle protein synthesis and reducing proteolytic gene expression
• Because ActRIIB also binds BMP9 and BMP10, which maintain vascular endothelial homeostasis, systemic blockade carries an inherent off-target liability for vascular adverse events
• The broad-spectrum ligand trapping confers greater anabolic potency compared with myostatin-selective monoclonal antibodies, but at the cost of reduced selectivity

Pharmacokinetics (ADME)

Half-life

Approximately 10–15 days (mean terminal half-life in a single-ascending-dose Phase 1 study, SC administration, postmenopausal women; PMID 23169607)

Clearance

Not formally published; linear AUC and Cmax with dose at 0.02–3 mg/kg SC in Phase 1 (PMID 23169607)

PK–PD note: Pharmacodynamic lean-mass increases were detectable by DXA at Day 29 after a single 3 mg/kg SC dose; the extended half-life supported monthly dosing in Phase 2 trials.…

Reading the evidence

• Evidence quality and gaps vary by application — see the cited grades above.
• Indexed-article counts span all evidence tiers, not only completed human trials.
• No first-party human-dosing, efficacy, or benefit claims are made here.

Key reviews & evidence-gap sources

• Suh J, Lee YS. Myostatin Inhibitors: Panacea or Predicament for Musculoskeletal Disorders? J Bone Metab. 2020;27(3):151-165. — Narrative review covering ACE-031 (ActRIIB-IgG1) clinical trial outcomes and off-target TGF-β family effects (BMP9/10 vascular side effects).
• Thevis M, Schänzer W. Emerging drugs affecting skeletal muscle function and mitochondrial biogenesis - Potential implications for sports drug testing programs. Rapid Commun Mass Spectrom. 2016;30(5):635-51. — Anti-doping/sports drug testing review discussing ACE-031 as an emerging muscle-enhancing agent.
• Reichel C, et al. Gel Electrophoretic Detection of Black Market ACE-031. Drug Test Anal. 2025;17(10):1934-1946. — Analytical detection method for illicit/black-market ACE-031; documents diversion into unregulated supply.
• MDA Quest — Update: ACE-031 Clinical Trials in Duchenne MD — Disease-advocacy reporting of Acceleron/Shire program discontinuation (May 2013).

4 registered trials — 0 currently recruiting.

Phase 2
NCT01239758
Extension Study of ACE-031 in Subjects With Duchenne Muscular Dystrophy

TERMINATED

Phase 1
NCT00755638
A Safety, Tolerability, Pharmacokinetic and Pharmacodynamic Study of ACE-031 (ActRIIB-IgG1)in Healthy Postmenopausal Volunteers

COMPLETED

Phase 2
NCT01099761
Study of ACE-031 in Subjects With Duchenne Muscular Dystrophy

TERMINATED

Phase 1
NCT00952887
A Safety, Tolerability, Pharmacokinetic and Pharmacodynamic Study of ACE-031 in Healthy Postmenopausal Women

COMPLETED

Summary (literature)

Clinical trials identified a characteristic vascular adverse-event cluster attributable to off-target capture of BMP9 and BMP10: epistaxis (nosebleeds), gingival bleeding, and cutaneous telangiectasias — findings resembling hereditary hemorrhagic telangiectasia (HHT). In the Phas…

WADA status

Prohibited in-competition and out-of-competition under WADA 2026 Prohibited List, Section S4.3 'Agents Preventing Activin Receptor IIB Activation' (non-Specifie…

Dominant research route: SC

Single ascending dose (0.02–3 mg/kg SC) in 48 healthy postmenopausal women (Phase 1); multiple ascending dose in healthy postmenopausal women (Phase 1, NCT00952887); multiple ascending dose in ambulatory boys with Duchenne muscular dystrophy (Phase 2, SC every 2–4 weeks)

Bioavailability: SC administration; reported linear increase in AUC and Cmax with dose and median terminal half-life of approximately 10–15 days, consistent with slow systemic absorption from the injection depot and Fc-fusion pharmacokinetics

ACE-031 (ActRIIB-IgG1) is a recombinant fusion protein of the activin receptor type IIB extracellular domain and human IgG1 Fc; all registered human studies administered it subcutaneously. No IV, IM, IP, PO, IN, or TOP routes were studied in the cited human trials.

Animal & human figures are kept visibly separate so studied animal doses are never misread as human guidance.

Sorted A–Z by vendor — never by price

Weekly median $/mg from the live vendor crawl.

Researched storefront prices, bucketed

p25 $104.59 · median $144.50 · p75 $160.25 · 8 researched vendors

Legit, COA-backed band: $81.75–$173.00/mg.

Value rule: don't just buy the cheapest — a price under $3/mg is a red flag. Pair price with COA and independent-test grade.

Estimated cost of research (10 mg)

Vial (best researched price)

$700

Bacteriostatic water (generic estimate)

$6

Syringes / supplies (generic estimate)

$12

What each test proves — general guidance, plus this compound's researched purity data

Purity on the current market (researched)

No independent lab (Janoshik/MZ Biolabs/Finnrick) purity percentage range for ACE-031 was located. The Reichel et al. 2025 analytical study found that 0 of 14 black-market products contained the authentic ACVR2B-Fc fusion protein; 12 contained full-length human ACVR2B (with additional contaminating proteins) and 2 contained no ACVR2B-immunoreactive protein.

Independent labs cited for this compound

No FDA recall or Enforcement Report entries specific to ACE-031 were found. ACE-031 was never FDA-approved, so no approved-product recall pathway applies; the compound's market presence is limited to unapproved 'research chemical' sales.

Buyer red-flag checklist

• ACE-031 was never FDA-approved for any indication; all 'research chemical' sales are unapproved.
• Phase 2 DMD clinical development was terminated in 2011-2013 due to vascular adverse events (epistaxis, gingival bleeding, telangiectasias).
• WADA Prohibited List (S4.3) explicitly names ACE-031 as a banned substance; athletes face sanctions.
• Reichel et al. 2025 found 0 of 14 black-market products contained authentic ACE-031 (ACVR2B-Fc); 12 contained full-length human ACVR2B instead.
• No specific FDA Import Alert for ACE-031 was identified; the peptide falls under general unapproved-drug import scrutiny rather than a named DWPE alert.
• No Janoshik/MZ Biolabs/Finnrick public purity testing data for ACE-031 was located, limiting independent quality verification.

GMP vs research-grade: the chemistry (SPPS + HPLC + MS) is identical — the difference is the quality system.

Underdosing / mislabeling: Independent lab testing specific to ACE-031 dosing/potency (Janoshik/MZ Biolabs/Finnrick aggregates) was not located. The Reichel et al. 2025 study (Seibersdorf doping control lab / German Sport University Cologne) is the closest peer-reviewed quality assessment: it found 100% of 14 black-market samples were misidentified (full-length ACVR2B rather than the Fc-fusion), indicating a counterfeit/misidentification problem rather than a conventional underdosing pattern.

• An RUO label is not an import exemption — CBP judges actual intended use.
• Lyophilized powder is ambient-stable in transit; temperature control needed for > 7-day transit.
• US-warehouse vendors dodge import scrutiny — they cost more but ship more reliably.

Every item dated & sourced

Prohibited. ACE-031 is listed by name under WADA Prohibited List Section S4.3 'Agents Preventing Activin Receptor IIB Activation' as an example of 'decoy activin receptors (e.g. ACE-031)'.

No granted patents identified in current seed. Composition-of-matter coverage is limited given the peptide's synthetic origin.

• IACUC / IRB research context
• RUO buyer responsibilities & documentation
• Veterinary / alternative-use where lawful
• Jurisdiction-aware "who may lawfully obtain"

What people discuss

Reported concerns — discussion, not established effects

Reading caveats

• small self-selected forum sample
• grey-market sourcing bias
• anecdotal self-experimentation without verification
• skeptic over-representation on bodybuilding boards
• no controlled dosing context

Manually researched from reddit— theme weights are research estimates, not live counts; aggregated & de-identified. No individual posts, quotes, or usernames are ever shown.

Relative research / market volume — populated once the activity stream is wired

Inline tooltips for lyophilized, RUO, EU/mg, SPPS, 503A and more.

Toggle plain-language ↔ scientific in the header.

• How to read a COA
• Free base vs acetate
• Understanding evidence grades

Recombinant ActRIIB-IgG1 decoy receptor that traps myostatin and activins to suppress TGF-beta-mediated inhibition of skeletal muscle growth. Approximately 12 articles are indexed (literature last scanned 2026-05-29). US regulatory status: Inactive IND / no active development; unapproved biologic. Research use only.

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