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ACE-031

Soluble activin receptor type IIB · ActRIIB-Fc

Think of it as a muscle-building bouncer.

ACE-031 acts like a bouncer at a club, keeping certain proteins from getting in and messing with your muscle growth. Normally, proteins like myostatin put the brakes on muscle building, but ACE-031 blocks these proteins, potentially allowing for more muscle mass.

Early studies showed promising results for increasing lean body mass, especially in contexts where muscle growth is beneficial, like in postmenopausal women. However, despite these initial gains, research hit a pause due to some non-muscle-related safety concerns.

Who it's for

  • Fitness enthusiasts looking for cutting-edge muscle-building insights
  • Bodybuilders curious about future muscle growth technologies
  • Athletes interested in muscle mass research

Probably not for you if…

  • Anyone seeking FDA-approved muscle growth solutions
  • Individuals uncomfortable with experimental therapies
  • Those prioritizing safety-confirmed products

Editorial summary for research context · Not medical advice

Mechanism of Action

ACE-031 is a recombinant fusion protein combining the extracellular domain of the activin receptor type IIB with an Fc region. Acting as a decoy receptor, it binds myostatin, activin, and related TGF-β family ligands in circulation, preventing them from activating muscle-cell ActRIIB and downstream Smad signaling. Early-phase human trials (Acceleron Pharma) in Duchenne muscular dystrophy showed lean-mass gains but were discontinued in 2013 due to non-muscle safety signals (epistaxis, telangiectasias). ACE-031 is not FDA-approved.

Researched Benefits

Myostatin and activin pathway blockade

Preclinical and Phase 1 data demonstrate ActRIIB-Fc inhibits multiple negative regulators of muscle mass.

  • [Attie et al. 2013]

Lean mass increase in early human trials

A Phase 1 study in healthy postmenopausal women showed increases in lean body mass and bone formation markers.

  • [Attie et al. 2013]

Explored in Duchenne muscular dystrophy

Phase 2 trials in DMD showed initial functional signals before discontinuation due to safety concerns.

  • [Campbell et al. 2017]

Research Protocols

The following dosing ranges have appeared in published research protocols. Presented for informational purposes only — not a recommendation for human use.

Historical Phase 1 research dose

Dosage
1 mg
Frequency
every 4 weeks
Timing
any time
Cycle
12 weeks

Research protocols in the discontinued clinical program used mg/kg IV/SC dosing every 3-4 weeks; ACE-031 is no longer in active human development.

Reported Side Effects

  • Epistaxis (nosebleeds) — cited reason for clinical program discontinuation
  • Telangiectasias (small dilated blood vessels)
  • Injection-site reactions
  • Gum/mucosal bleeding reports
  • Theoretical off-target effects on other TGF-β pathway tissues
  • Long-term human safety data is absent

Contraindications

  • Active or suspected malignancy
  • Bleeding disorders or anticoagulant therapy
  • Pregnancy and lactation
  • Vascular disease

Stacking Partners

Peptides commonly paired with ACE-031 in published research and protocol write-ups.

performance

Follistatin

Myostatin neutralization

performance

MGF

Satellite cell activation (preclinical)

performance

IGF-1 LR3

Extended IGF-1 receptor activation

Vendor Pricing

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Gear + Companions

Reconstitution supplies and research-backed supplement companions for ACE-031. Editorial picks only — we earn a commission through Amazon on the click, no sponsorship.

Gear you'll need

· Reconstitution + storage essentials

  • Bacteriostatic Water 30mL (0.9% Benzyl Alcohol)

    Empower Pharmacy / generic medical supply

    Reconstitutes every lyophilized peptide. 28-day viability refrigerated.

    View at Pantheon →

  • Insulin Syringes 31G × 5/16" × 0.5mL (100 count)

    EasyTouch

    31G × 0.5mL insulin syringes — the default size for sub-0.25mL peptide doses.

    Buy on Amazon →

  • Alcohol Prep Pads (Sterile, 200 count)

    Dynarex

    Sterile 70% IPA prep pads — one per vial stopper + one per injection site.

    Buy on Amazon →

  • 1-Quart Sharps Disposal Container

    BD / Becton Dickinson

    FDA-cleared sharps container — pharmacies won't accept improvised disposal.

    Buy on Amazon →

As an Amazon Associate we earn from qualifying purchases · Disclosed per FTC guidelines

Top Videos

Curated from YouTube — refreshed weekly. Stacked doesn't host or endorse external content.

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Research Papers

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

    Attie KM, et al. · Muscle & Nerve · 2013

    PubMed 23169607 →