Peps
What is ACE-031?
ACE-031, also called ramatercept, is a large lab-made protein rather than a short peptide. It works as a decoy receptor that binds myostatin and related signals that normally hold back muscle growth. It was tested in boys with Duchenne muscular dystrophy, but that phase 2 trial was stopped early because of nosebleeds and small dilated blood vessels (telangiectasias), and it has never been approved.
Biological role or research focus
Blocking myostatin and related muscle-limiting signals; development stopped.
A small safety trial that was stopped early, so the muscle and walking findings are trends, not proof of benefit. Several authors worked for the developer. The side effects that ended the trial were not related to muscle, and the results say nothing in favor of using ACE-031 for muscle building in healthy people.
Names you may encounter
Ramatercept · ACE031
Search terms can include brands, combinations, or historical names. They are not automatic product equivalents.
- Class / identity
- Large fusion protein made from the signal-binding part of the activin type IIB receptor (ActRIIB) joined to a human antibody fragment (IgG1 Fc); not a short peptide
- Research focus
- Blocking myostatin and related muscle-limiting signals; development stopped
- Featured evidence
- Human randomized phase 2 trial
- Source check
- October 15, 2026
What does the evidence show?
Evidence map
Every study featured on this page, grouped by what was actually tested. Human studies count most; animal and cell results often do not carry over to people.
| Study | Type | Population / model |
|---|---|---|
| ACE-031 in boys with Duchenne muscular dystrophy (stopped early) (2017) | Human randomized phase 2 trial | Boys with Duchenne muscular dystrophy who could still walk. |
Selected published evidence, with the population, findings, and limits kept together. These original summaries draw on publication abstracts; they are not a systematic review.
Human randomized phase 2 trial · 2017
ACE-031 in boys with Duchenne muscular dystrophy (stopped early)
What did this publication test, and what did it find?
- Population / model
- Boys with Duchenne muscular dystrophy who could still walk.
- Study design
- Randomized, double-blind, placebo-controlled trial in which successive groups received increasing dose levels of ACE-031 or placebo. Its main purpose was to check safety; secondary aims measured how the body handled the drug and its effects on muscle, fat and bone.
- Main finding
- ACE-031 was not linked to serious or severe adverse events, but the study was stopped after the second dose level because of nosebleeds and telangiectasias (small dilated blood vessels). Treated boys showed a trend toward keeping their 6-minute walking distance while the placebo group declined, which was not statistically significant, and trends toward more lean mass and bone density and less fat mass.
- Limits & context
- A small safety trial that was stopped early, so the muscle and walking findings are trends, not proof of benefit. Several authors worked for the developer. The side effects that ended the trial were not related to muscle, and the results say nothing in favor of using ACE-031 for muscle building in healthy people.
Read the original paper for methods, adverse events, funding, and conflicts of interest. Publisher access may require a subscription.
Registered human trials
No study naming ACE-031 as an intervention was found on ClinicalTrials.gov when we last checked (October 15, 2026). That means no registered human trial, not proof that none has ever been done elsewhere.
Search additional PubMed records ↗Risks & interactions
ACE-031 is a discontinued experimental protein drug. Its trial in boys with muscular dystrophy was stopped over nosebleeds and dilated blood vessels, and black-market products tested did not contain it.
Human data come from a single-dose study in 48 healthy postmenopausal women and a phase 2 trial in boys with Duchenne muscular dystrophy that was stopped early. Effects of longer use were never studied.
It isn't approved, so there is no official list of who should avoid it, and its human studies are too small to show who is most at risk. No condition is tagged, but that does not make it safe for anyone. If a condition applies to you, talk to a doctor or pharmacist first.
Who should not use it
There is no official list, because it has never been approved as a medicine. That is not a sign it is safe for anyone: its risks have not been studied enough to know who is most at risk.
Serious risks
- Nosebleeds (epistaxis) and telangiectasias (small dilated blood vessels) in boys with Duchenne muscular dystrophy, which led to the phase 2 trial being stopped
- Black-market products sold as ACE-031 contained a different receptor protein plus many unlisted proteins, or no receptor protein at all
Side effects reported in studies
- injection-site redness
Summarized from published studies with AI assistance; not reviewed by a clinician. Not a complete list, and not medical advice: talk to a doctor or pharmacist about your own situation. Checked 2026-10-10. Sources: ACE-031 phase 2 trial in Duchenne muscular dystrophy (Muscle Nerve, 2017) ↗ · ACE-031 single-dose study in healthy volunteers (Muscle Nerve, 2013) ↗ · Detection of black market ACE-031 (Drug Test Anal, 2025) ↗
Safety & what remains unknown
In boys with Duchenne muscular dystrophy, nosebleeds and telangiectasias (small dilated blood vessels) led to the trial being stopped. In healthy women given a single dose, redness at the injection site was reported. Effects of longer use are unknown, and black-market products tested by an anti-doping laboratory did not contain ACE-031.
Evidence boundaries
A small safety trial that was stopped early, so the muscle and walking findings are trends, not proof of benefit. Several authors worked for the developer. The side effects that ended the trial were not related to muscle, and the results say nothing in favor of using ACE-031 for muscle building in healthy people.
Regulatory status
- U.S. FDA approval
- Not approved
No FDA-approved drug containing this substance found in Drugs@FDA (openFDA, checked October 15, 2026). Its development for Duchenne muscular dystrophy was stopped. source - FDA compounding (503A bulk list)
- Not on FDA’s compounding lists
Not found on FDA's 503A category 1, 2 or 3 lists (updated May 14, 2026) or the category 2 safety-risk page (checked October 15, 2026). source - World Anti-Doping Agency (2026)
- Prohibited, named on the list · S4.3 Agents preventing activin receptor IIB activation
Named explicitly ("ACE-031") as an example of a decoy activin receptor. source
Other notes
- The phase 2 trial in Duchenne muscular dystrophy (NCT01099761) and its extension study (NCT01239758) were terminated in 2011 "based on preliminary safety data"; no later ACE-031 trials are registered (checked October 15, 2026). source
- An anti-doping laboratory found that 14 black-market products sold as ACE-031 did not contain ACE-031 (2025). source
Checked October 8, 2026. Rules change; follow the source links for the current status. Regulatory tracker.
This is not a complete list of contraindications, interactions, or adverse effects. Medicine labels apply to specific products and indications; research-use listings are not interchangeable with approved medicines.
Research context & identity
This profile covers a discontinued investigational drug. ACE-031 was developed by Acceleron Pharma for Duchenne muscular dystrophy; its phase 2 trial and extension study were terminated in 2011 based on preliminary safety data, and no later human trials are registered on ClinicalTrials.gov (checked October 15, 2026). It is not approved anywhere. The World Anti-Doping Agency names ACE-031 on its Prohibited List as an example of a decoy activin receptor, and sellers list it as a research chemical.
In an earlier single-dose study in 48 healthy postmenopausal women, ACE-031 was generally well tolerated, with redness at the injection site among the reported side effects. In the highest dose group, lean body mass rose by about 3% and thigh muscle volume by about 5% after four weeks.
An anti-doping laboratory analysis of 14 black-market products sold as ACE-031, published in 2025, found that none contained ACE-031 itself. Twelve contained the full-length activin type IIB receptor protein together with many other proteins, and two contained no receptor protein at all.
Source: A single ascending-dose study of muscle regulator ACE-031 in healthy volunteers · 2013 ↗
Source: Gel electrophoretic detection of black market ACE-031 · 2025 ↗
Source: ClinicalTrials.gov · ACE-031 studies · checked October 15, 2026 ↗
New editorial updates
New source discoveries
Links appear automatically. Unreviewed discoveries are not verified medical findings.
Sources & supplier listings
Listings are grouped by the vendor’s stated identity. Blends and modified derivatives are labeled separately. Inclusion is not a quality assessment or an endorsement.
Some seller links are affiliate links, and codes such as PEPSRADAR credit PepsRadar; PepsRadar may earn a commission. Affiliate disclosure. For laboratory research use only. Not for human consumption.
ACE-031 (ramatercept) (1 mg)
Disguised Alpha · Vendor-labeled research use only
$59.99 · from $59.99/mg
Listed in stock · Snapshot 2026-10-15
Options may vary. Shipping and tax excluded.
10% off with code PEPSRADAR · PepsRadar earns a commission on this code
Catalog checked 2026-10-04. Seller listings retain their stated intended use. Shops covered: BioLongevity Labs, BioLongevity Supplements, American Peptides, PSPeptides, Alera Research, Pinnacle Peptide Labs, Certified Pep, Peptide.Express, Purgo Labs, Offline Peptides, Ascension Peptides, OMNI Peptides, Disguised Alpha. This is not a market-wide comparison. Affiliate participation does not determine evidence or editorial coverage.
Biology & proposed mechanism
Myostatin and related signaling proteins act through the activin type IIB receptor to limit muscle growth. ACE-031 contains the outer, signal-catching part of that receptor fused to an antibody fragment, so it binds these signals before they reach muscle. Because it is not specific to myostatin, it also binds related signals, and its effects reach beyond muscle: in the featured trial, trends were seen in fat mass and bone density as well as lean mass.
What are people discussing?
No editorial transcript note has been reviewed for this profile yet. Below are the matching video records available for exploration; title and caption matches are not verified claims.
Questions worth asking
- Is ACE-031 a peptide?
- What material, population, and route were actually studied?
- A small safety trial that was stopped early, so the muscle and walking findings are trends, not proof of benefit. Several authors worked for the developer. The side effects that ended the trial were not related to muscle, and the results say nothing in favor of using ACE-031 for muscle building in healthy people.
- What adverse effects, uncertainty, and conflicts of interest does the original source report?
Watch the source discussions
0 matching video records · 0 with captions indexed.
Across the full library, 29 caption files are indexed from 18,167 inventoried videos. Most transcripts remain unreviewed. Select a thumbnail or timestamp to watch inside PepsRadar. Thumbnail images load from YouTube.
No matching video has been identified in the current snapshot.
Frequently asked questions
Is ACE-031 a peptide?
Not in the usual sense. It is a large engineered protein built from part of a receptor joined to an antibody fragment, far bigger than the short peptides covered on most of this site. It is included because sellers list it alongside peptides.
Does the publication verify a supplier’s product?
No. The tested material and a commercial listing need separate identity and batch checks. A research-use disclaimer does not establish clinical suitability.
References & editorial record
- PubMed · PMID 27462804 ↗
- A single ascending-dose study of muscle regulator ACE-031 in healthy volunteers · 2013 ↗
- Gel electrophoretic detection of black market ACE-031 · 2025 ↗
- ClinicalTrials.gov · ACE-031 studies · checked October 15, 2026 ↗
Source notes checked 2026-10-15. Original PepsRadar summaries. Not reviewed by a medical professional. Topic grouping is editorial navigation, not a treatment recommendation. Video notes specify which excerpts were reviewed; no full transcripts are published.