The Peptide Nook

ACE-031

In plain English

ACE-031 is a lab-made decoy receptor that soaks up myostatin and related signals, the body’s natural brakes on muscle growth. It was tested in people with muscular dystrophy and produced quick increases in muscle, but development stopped because of side effects.

What it's used for

  • Muscle growth
  • Muscle-wasting conditions (development stopped)

Benefits

In human studies, a single dose increased lean mass and thigh muscle volume within weeks in healthy older women, and in boys with Duchenne muscular dystrophy it showed trends toward more muscle and better walking. Users report rapid gains in muscle fullness.

How it works

In simple terms: it is a sponge that soaks up myostatin before it can reach muscle.

It is the outer part of the activin type IIB receptor joined to an antibody fragment. It binds myostatin, activin and related proteins in the blood, so they cannot slow muscle growth. Some of those proteins also control blood vessels, which explains its side effects.

Development history

  • 2000s: Developed by Acceleron Pharma, later partnered with Shire.
  • 2011: Phase 2 trial in Duchenne muscular dystrophy begins.
  • 2013: Development stopped after nosebleeds and small dilated blood vessels in the skin and gums.

Typical protocols

Educational information only, not medical advice. The information below describes how this peptide has been used in research, on prescription labels or by users. It is not a recommendation. Talk to a qualified healthcare professional before starting, stopping or changing anything.

There is no established dose. Users commonly report the following.

Use Dose Frequency Length
Muscle growth About 1 mg Once or twice a week 4 weeks

Cycling

Short courses with long breaks.

Administration options

Subcutaneous injection.

Reconstitution and dosing calculator

Usually comes in 1 mg vials, mixed with 1 mL of bacteriostatic water. It is a large, fragile protein: mix very gently.

1Peptide in the vial

The total amount printed on the vial label.

2Bacteriostatic water added

More water makes each dose a bigger, easier-to-measure draw. It does not change how much peptide is in the vial.

3Dose per injection

Use the dose from your protocol or your clinician. 1 mg = 1,000 mcg.

4Your syringe

All three are U-100 insulin syringes: 100 units = 1 mL. Smaller barrels make small doses easier to read.

Draw your syringe to

– units

Volume to draw
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Concentration
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Each unit holds
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Doses per vial
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Show the math

    This tool does arithmetic only. It does not choose a dose or confirm that any substance is right for you. Double-check every result against your syringe and your clinician’s instructions.

    Side effects and safety

    • Nosebleeds, gum bleeding and small dilated blood vessels in the skin (telangiectasia) stopped its clinical development.
    • Fatigue and injection-site reactions.
    • It is a large protein that is hard to make; independent testing matters a great deal.
    • Avoid during pregnancy and breastfeeding.
    • Prohibited in competitive sport (WADA).

    Common stacks

    Usually used alone.

    Storage

    Powder: refrigerate or freeze. After mixing: refrigerate at 2–8 °C and use within about 2 weeks.

    Compare with

    • Follistatin-344: also blocks myostatin.
    • IGF-1 LR3: pushes growth forward rather than removing a brake.

    Frequently asked questions

    Why was it stopped?

    In the Duchenne trial, some boys developed nosebleeds and dilated blood vessels, so the sponsor halted development.

    References

    1. Attie KM, et al. A single ascending-dose study of muscle regulator ACE-031 in healthy volunteers. Muscle Nerve. 2013;47(3):416-423.
    2. Campbell C, et al. Myostatin inhibitor ACE-031 treatment of ambulatory boys with Duchenne muscular dystrophy. Muscle Nerve. 2017;55(4):458-464.
    Educational information only. Not medical advice. Always consult a qualified healthcare professional.

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