ACE-031 (ramatercept) is a soluble ActRIIB-Fc fusion protein that traps myostatin and related TGF-β superfamily ligands. By removing myostatin’s brake on muscle growth, Phase 1 work in healthy volunteers showed increases in lean mass and thigh muscle volume. It is not FDA-approved.

Why was ACE-031 development stopped?

Clinical development was discontinued after bleeding-related adverse events — notably epistaxis (nosebleeds) and telangiectasias — attributed in part to off-target BMP9 inhibition affecting vascular remodeling. The Duchenne muscular dystrophy trial literature documents these safety signals.

What dose was used in trials?

Trials used infrequent subcutaneous dosing in the low-milligram range on schedules often every 2–4 weeks, consistent with a ~10–15 day half-life. Those schedules are historical clinical-trial context only — not consumer guidance. There is no approved dose.

How does ACE-031 compare to follistatin-344?

Both sit in the myostatin / TGF-β superfamily antagonism space. Follistatin binds and sequesters myostatin and activins as an endogenous glycoprotein isoform; ACE-031 is an engineered soluble receptor trap (ActRIIB-Fc) with human trial PK/PD data and a known vascular safety liability that halted development. Neither is FDA-approved for muscle building.

ACE-031 (Ramatercept / ActRIIB-Fc) — Dosing, Side Effects, FDA Status & Research | PeptIQ

What is ACE-031?

ACE-031 (ramatercept) is a soluble ActRIIB-Fc fusion protein that traps myostatin and related TGF-β superfamily ligands to disinhibit muscle growth. Phase 1 healthy-volunteer data showed lean-mass and thigh-muscle volume increases, and Phase 2 work explored Duchenne muscular dystrophy — but clinical development was discontinued after bleeding-related adverse events (epistaxis, telangiectasias) linked to off-target BMP9 inhibition. Not FDA-approved; extreme caution.

Mechanism of Action

Soluble activin receptor type IIB extracellular domain fused to IgG1-Fc acts as a ligand trap for myostatin (GDF-8), activins, and related ligands; removes myostatin’s brake on muscle satellite-cell activation and fiber hypertrophy; off-target BMP9 binding implicated in vascular adverse events

Target: Myostatin (GDF-8), activins, and other ActRIIB ligands; BMP9 (off-target safety concern)

Research Indications

Tissue RepairMost Effective

Demonstrated acceleration of wound healing and soft tissue repair in research

Gut HealthEffective

Research shows beneficial effects on intestinal lining and GI function

Joint SupportEffective

Associated with reduced joint inflammation and improved mobility

Muscle RecoveryModerate

May support faster recovery from muscle strains and exercise stress

Research Protocols

These are commonly discussed research protocols — not medical advice. Consult a healthcare provider before use.

Goal	Dose	Frequency	Route
Phase 1 Trial Context (healthy volunteers)	0.02–3 mg/kg range studied; lean-mass signal at low-mg SubQ	Single ascending dose / infrequent	Subcutaneous injection
DMD Trial Context	Protocol-defined mg SubQ (development halted)	Every 2–4 weeks in trial schedules	Subcutaneous injection
Evidence Boundary	No approved or recommended consumer dose	Do not self-titrate — development stopped for safety	Qualified laboratory/professional protocol only

Peptide & Drug Interactions

Always consult your healthcare provider before combining with other compounds. Use our Interaction Checker for reference.

Anticoagulants / antiplateletsAvoid

Follistatin-344 / other myostatin inhibitorsAvoid

NSAIDs (bleeding risk)Caution

IGF-1 LR3Caution

TB-500Monitor

BPC-157Compatible

How to Reconstitute & Inject

Use bacteriostatic (BAC) water only. Avoid saline — may cause precipitation. Refrigerate and use within 28 days.

1
Remove ACE-031 vial from refrigeration and allow to reach room temperature (15–20 minutes)
2
Clean vial top with alcohol swab and allow to air dry completely
3
Using a sterile syringe, draw the calculated volume of bacteriostatic water (BAC water)
4
Inject BAC water slowly down the side of the vial — do not aim directly at the powder
5
Gently swirl in circular motions — DO NOT shake vigorously as this degrades the peptide
6
Allow 2–3 minutes for full dissolution — solution should be clear and colorless
7
Draw calculated dose into an insulin syringe for subcutaneous injection
8
Inject into abdomen, thigh, or upper arm. Rotate injection sites to prevent lipodystrophy
9
Store reconstituted solution refrigerated (2–8°C) and use within 28 days

What to Expect

Week 1–2

Initial anti-inflammatory effects begin. Reduced pain and swelling in target area.

Week 2–4

Improved tissue mobility and reduced discomfort. Early healing acceleration.

Week 4–8

Significant recovery milestones. Stronger tissue repair and functional improvement.

Week 8–12

Near-complete healing in many cases. Improved strength and tissue integrity.

Side Effects & Safety

Bleeding-related adverse events — notably epistaxis (nosebleeds) and telangiectasias — that halted clinical development
Vascular remodeling effects attributed to off-target BMP9 inhibition
Increased bleeding risk when combined with anticoagulants, antiplatelets, or NSAIDs
Injection site reactions (redness, bruising, discomfort)
Human safety is not established — development was discontinued for safety and there is no approved dose

FDA Status & Regulatory Info

Research Only — Development Halted

ACE-031 (ramatercept) is a soluble ActRIIB-Fc fusion protein that traps myostatin and related TGF-β superfamily ligands to disinhibit muscle growth. Phase 1 healthy-volunteer data showed lean-mass and thigh-muscle volume increases, and Phase 2 work explored Duchenne muscular dystrophy — but clinical development was discontinued after bleeding-related adverse events (epistaxis, telangiectasias) linked to off-target BMP9 inhibition. Not FDA-approved; extreme caution.

Rx Required: No

503A Ban: No

Telehealth: N/A

Full FDA Status Tracker

Frequently Asked Questions

Research References

External links for education only. We do not control third-party content.