ACE-031

Early human

Recombinant ActRIIB-Fc fusion protein; myostatin/activin signaling decoy receptor · Also known as ACVR2B-Fc, ActRIIB-Fc, Ramatercept

Overview

ACE-031 (ramatercept) is a recombinant fusion protein combining the extracellular domain of the activin receptor type IIB (ActRIIB) with an antibody Fc region, designed to act as a 'decoy' that soaks up myostatin and related TGF-beta proteins to release the brake on muscle growth. It is not FDA-approved, and importantly its development was discontinued: a Phase 2 trial in boys with Duchenne muscular dystrophy was halted in 2011 over safety signals (nosebleeds and small dilated blood vessels, telangiectasias, attributed to off-target effects on related signaling proteins), and the developers ended the program in 2013. So while early data suggested it could increase muscle and lean mass, the human story is one of a stopped program rather than a proven therapy. Any current 'ACE-031' offered for sale is unapproved.

Commonly Reported Uses

These are uses commonly discussed or marketed by users and vendors — not a list of proven or approved benefits, and not a recommendation.

Duchenne muscular dystrophy / muscle-wasting disease (investigational; trials halted, never approved)
Muscle growth and lean-mass gain (marketed claim; based on a discontinued program, not approved)
Strength and body recomposition (marketed claim; human evidence from a halted trial only)

What to Track

Data points you and your clinician might monitor. For observation only — not a diagnostic protocol.

InBody/DEXA — skeletal muscle mass and lean body mass against a baseline
Smart scale — weight and body-fat % trend
Subjective daily check-ins — including bleeding/nosebleeds or skin vascular changes, which were the trial safety signals
WHOOP — recovery score and HRV trend
Labs — a clinician-monitored panel if exposure is being watched

Sources & References

Quick Reference

Class: Recombinant ActRIIB-Fc fusion protein; myostatin/activin signaling decoy receptor
Evidence Level: Early human
Reported Uses: 3 listed
Tracking Metrics: 5 suggested
Citations: 3 sources

Safety & legal notes

NOT FDA-approved; clinical development was discontinued. The Phase 2 Duchenne trial was halted in 2011 after vascular adverse events (epistaxis/nosebleeds and telangiectasias) linked to off-target inhibition of related BMP signaling, and the program was ended in 2013. Long-term human safety is therefore not established. Prohibited in sport at all times under the WADA Prohibited List (S2: Peptide Hormones, Growth Factors) as an agent that modifies myostatin function. Educational information only, not medical or legal advice. Consult a licensed clinician.

Track your protocol in Peplens

Connect your InBody, Whoop, smart scale, and nutrition data. See your Overlay — all metrics, one clear read.

Get started free →

← All entries

Educational disclaimer

EDUCATIONAL INFORMATION ONLY — NOT MEDICAL ADVICE. The information in this dataset is compiled from published research, regulatory filings, and reputable secondary sources for educational purposes. It does not constitute medical, legal, or professional advice and is not a substitute for consultation with a licensed healthcare provider. Many compounds listed here are NOT approved by the U.S. Food and Drug Administration (FDA) for human use; some are sold only as research chemicals, some are available only via compounding pharmacies with a prescription, and many are prohibited in competitive sport under the World Anti-Doping Agency (WADA) Prohibited List. Regulatory status changes frequently — the 2026 FDA compounding reclassification is an active, evolving situation and reclassification is NOT the same as FDA approval. Individual results vary. Always consult a qualified, licensed healthcare provider before starting, stopping, or modifying any peptide, supplement, or health protocol. Peptide OS is a personal data-tracking tool and an educational publisher; it does not sell, prescribe, dispense, or facilitate the sale of any drug or peptide.