Activin-receptor fusion protein · Fact sheet
ACE-031
Also known as Ramatercept
ACE-031 is an experimental activin-receptor fusion protein studied to reduce growth-inhibiting signals in muscle. Its Duchenne muscular dystrophy study stopped because of nosebleeds and visible small-vessel changes; muscle-mass signals do not establish safe bodybuilding use.
What is ACE-031?
The protein combines part of activin receptor type IIB with an antibody Fc region. It traps several ligands, including myostatin-related signals.
Broad ligand binding is different from selectively blocking myostatin alone.
Benefits & claims
Interest centers on muscle wasting and whether inhibiting growth brakes can improve strength and function.
What the evidence supports
- The Duchenne study observed trends in lean mass, fat mass and walking performance.
- The walking comparison was not statistically significant.
- A later marmoset study is preclinical evidence and cannot resolve the human safety problem.
Research areas
- Duchenne muscular dystrophy
- Muscle mass
- Activin/myostatin pathway
Dosage & frequency
No established human regimenThe reviewed sources do not establish a human treatment amount or frequency for ACE-031. Animal and laboratory exposures are not human regimens.
How to read these amounts
An approved regimen belongs to a specific product, indication, and population. A study regimen describes what researchers tested; it does not establish a prescription or a safe self-use protocol. Products, routes, and formulations are not interchangeable. A prescriber uses the full label and individual clinical circumstances.
Personal accounts may describe amounts, schedules and outcomes beyond clinical research. They do not establish a regimen. Read the reported experiences
Formulations, interactions & practical context
- Identity and pharmacology
- The protein combines part of activin receptor type IIB with an antibody Fc region. It traps several ligands, including myostatin-related signals.
Formulation differences
- Broad ligand binding is different from selectively blocking myostatin alone.
Interactions & precautions
- The reviewed sources do not establish a comprehensive human interaction profile for this exact substance or combination.
What is still unresolved
- Meaningful functional benefit
- Vascular safety and ligand selectivity
- Whether any exact formulation can support a favorable human benefit-risk balance
Side effects & risks
- Epistaxis (nosebleeds) and telangiectasias (visible dilated small blood vessels) contributed to stopping the trial.
- Blocking multiple signaling ligands can produce effects outside muscle; long-term risks remain uncertain.
This is a summary of the cited evidence, not a complete product label. A lack of human safety data does not establish safety.
Clinical research
Early human evidenceHuman early-phase research found pharmacodynamic signals, but the Duchenne study did not show a statistically significant walking advantage and stopped early.
Studies
Stopped after the second dosing regimen because of vascular adverse events.
Preclinical muscle-mass and contractile findings.
Analytical detection paper; product identity is separate from clinical testing.
Personal experiences
Reports describe what someone noticed. They cannot establish cause, typical results, or how often a side effect happens. Amounts and schedules describe the individual account, not an effective or safe dose. Product identity and strength may be unverified, and missing details are left explicit.
No attributable personal accounts were found in the sources reviewed.
Approval status
ACE-031 has no FDA-approved product. The cited Duchenne trial was discontinued because of non-muscle safety concerns; recent primate research does not establish a restarted human program.
Referenced development program stopped
Approval covers the labeled product, use and population. A trial phase does not establish success; a stopped program is not ongoing research.
Open questions
- Meaningful functional benefit
- Vascular safety and ligand selectivity
- Whether any exact formulation can support a favorable human benefit-risk balance
Summary
A later marmoset study is preclinical evidence and cannot resolve the human safety problem.
Sources
Medical evidence and regulatory sources are listed here. Personal reports are linked separately in the experiences section.
- pubmedACE-031 Duchenne randomized study
Stopped after the second dosing regimen because of vascular adverse events.
- pubmedAnalysis of material labeled ACE-031
Analytical detection paper; product identity is separate from clinical testing.