Molecular profile
- Entry type
- Peptide research profile
Dosing & scaling, explained
Amounts reported for ACE-031 are listed under Reported protocols, each with its source and study kind. No amount ladder is inferred from them. This is educational source context, not a protocol or recommendation.
No source-supported amount ladder is shown
Enter a target amount only from your own reviewed source. The calculator can convert it into concentration, volume and device markings, but it will not infer an amount from product availability or another compound.
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No independently verified schedule
Clinical context
Human study rows are described per source under Reported protocols; they belong to their trial populations and are not a general amount.
Storage, handling and interpretation
Product identity
Verify the exact compound, formulation and amount against the product label or certificate before calculation.
Storage & handling
Follow the product label, certificate and validated laboratory SOP; no universal storage assumption is applied here.
Prepared solutions
Label concentration and preparation date, use sterile technique where applicable, and follow a validated stability protocol.
Reported protocols for ACE-031
What published studies and recent community write-ups report about amounts, timing and course length. 4 clinical, 2 preclinical and 3 community-reported rows, each linked to its source. These are descriptions of what others report, not instructions, and nothing here is medical advice.
| Context | Dose | Frequency | Route | Course | Source |
|---|---|---|---|---|---|
| Clinical4 rows | |||||
| Phase 1 single ascending-dose study48 healthy postmenopausal women randomised 3:1 to ACE-031 or placebo | 0.02-3 mg/kg as a single dose | One dose | Subcutaneous | Single dose, assessed to day 29Not applicable | Muscle and Nerve (PubMed)2013 |
| Exposure rose in proportion to dose and the mean terminal half-life was 10-15 days, which is the Fc region at work. In the 3 mg/kg group, total body lean mass rose 3.3% on DXA and thigh muscle volume rose 5.1% on MRI by day 29, from one injection. Injection-site redness was the adverse event named. This is a single-dose result in postmenopausal women, not a repeated-dosing regimen. | |||||
| Registry record for the phase 1 study48 healthy postmenopausal volunteers | 0.02-3 mg/kg, single ascending dose | One dose | Subcutaneous | Single doseNot applicable | ClinicalTrials.gov2008 |
| The ClinicalTrials.gov entry for the study above is listed as completed, sponsored by Acceleron Pharma, which the registry now records as a Merck subsidiary. A second phase 1 record, NCT00952887, enrolled 70 volunteers. These are the only ACE-031 trials ever brought to completion. | |||||
| Phase 2 trial in Duchenne muscular dystrophy, halted24 ambulatory boys with Duchenne muscular dystrophy, randomised against placebo | 0.5 mg/kg or 1.0 mg/kg | 0.5 mg/kg once every 4 weeks, or 1.0 mg/kg once every 2 weeks | Subcutaneous | 12 weeks as plannedNone; dosing stopped after the second regimen | Muscle and Nerve (PubMed)2017 |
| No serious or severe adverse events occurred, but the study was stopped after the second dosing regimen because of epistaxis and telangiectasias, that is nosebleeds and dilated small vessels in the skin. Six-minute walk distance trended towards being maintained while the placebo group declined, and lean mass, bone mineral density and fat mass also trended favourably, none of it statistically significant. The authors state plainly that non-muscle adverse events, not a lack of effect, ended the trial. | |||||
| Registry record for the halted phase 2 trial24 boys with Duchenne muscular dystrophy | 0.5 mg/kg every 4 weeks or 1.0 mg/kg every 2 weeks, with matching-volume placebo | Every 2 or 4 weeks | Subcutaneous | 12 weeks plannedTerminated before completion | ClinicalTrials.gov2010 |
| The registry lists this study as terminated, with the reason recorded as being based on preliminary safety data, and an end date of June 2011. A companion extension study, NCT01239758, was terminated on the same grounds after enrolling 11 participants. No ACE-031 trial has been registered since. | |||||
| Preclinical2 rows | |||||
| Primate study in common marmosetsCommon marmosets randomised to ACE-031 or Tris-buffered saline vehicle | 3.0 mg/kg | Once weekly | Interscapular subcutaneous injection | 14 weeksNot applicable | PLOS One (PubMed Central)2026 |
| Lean body mass at the end of dosing was higher than baseline in treated marmosets but not in vehicle controls, biceps brachii fibre cross-sectional area rose in both type I and type II fibres, and extensor digitorum longus force rose when measured ex vivo. The authors report the drug was generally well tolerated in this species. The paper was published in 2026 by former Acceleron staff, long after the company abandoned the compound, and a marmoset dose does not translate to a person. | |||||
| Rat administration study of material sold online as ACE-031Rats given a single dose of a black-market product labelled ACE-031 | 10 mg/kg body weight | Single dose | Injection | Serum and urine sampled to 168 hoursNot applicable | Drug Testing and Analysis (PubMed Central)2025 |
| An Austrian doping-control laboratory bought 14 products sold online as ACE-031. Only 12 contained any protein reactive to activin receptor IIB antibodies, and mass spectrometry showed all 12 held full-length human activin receptor IIB rather than the Fc fusion that ACE-031 actually is; IdeS protease, which cuts IgG Fc regions, could not cut them. The products also carried many unrelated proteins. Giving black-market material to people was judged not ethically justifiable, so the administration arm used rats, where the protein was detectable in serum to 48 hours and never in urine. The paper also records ACE-031 as prohibited under section S4.3 of the WADA list. | |||||
| Community-reported3 rows | |||||
| Reference profile that declines to state amounts | No amount given; only the trials' 2 to 4 week interval and 10-15 day half-life | Not stated by the source | Subcutaneous | Not stated by the sourceNot stated by the source | Community resource2026 |
| This 2026 reference page argues that because development was stopped there is no validated regimen, no defined indication and no monitoring framework, and so deliberately gives no amounts, frequencies or schedules. It records ACE-031 by name under section S4.3 of the WADA Prohibited List as the worked example of a decoy activin receptor, prohibited in and out of competition. It also notes that a related trap from the same company, luspatercept, did reach approval, but for anaemia in beta thalassaemia rather than for muscle. | |||||
| Documentation of the grey-market vial against the trial figures | Trial figures restated: 0.02-3 mg/kg once, or 0.5-1.0 mg/kg every 2-4 weeks | Every 2 to 4 weeks in the trials | Subcutaneous | 12 weeks in the phase 2 trialNot described | Community resource2026 |
| This 2026 write-up stresses that every dose in the human literature is weight-based in milligrams per kilogram while the vials sold under the name carry a flat milligram label, and it calls its own vial page documentation rather than a protocol. It adds a detail from the doping-control analysis: among the 14 vials examined, one held follistatin and one held ipamorelin, an unrelated growth hormone secretagogue. This is a vendor-adjacent editorial source, not trial data. | |||||
| Community band reported against clinical amounts | 500-1500 mcg as a flat amount | Every 10 to 14 days | Subcutaneous | 12 weeks described, matching the halted trial10 weeks off described, with the page stating no cycling protocol is established | Community resource2026 |
| This community page records a flat 500-1500 mcg band and calculates it as roughly 50 to 400 times below the weight-based amounts used in the trials, then states that whether vascular risk scales with dose is unknown. It counts only about 15 to 30 people with documented personal experience, says forum discussion far outweighs actual use, and reports that some describe nosebleeds even at these amounts. It names April 2011 as when Acceleron halted the programme. These figures are community extrapolation from trial data, not a validated schedule. | |||||
How a course is commonly described
- Single doseClinical
The only well-measured human exposure is one subcutaneous injection. At 3 mg/kg, lean mass was already measurably higher by day 29, which is why the compound is still discussed more than a decade after it was abandoned.
- Weeks 1-6 of repeated dosingClinical
The phase 2 trial dosed every 2 or 4 weeks, which the 10-15 day half-life supports. This is the window in which the vascular signal appeared: nosebleeds and dilated skin vessels were reported on the more intensive regimen and were what stopped the study.
- Weeks 8-12Community-reported
Twelve weeks was the planned treatment period in the phase 2 trial and is the longest human exposure on record. Community pages describe the same 12-week frame at amounts far below the trial, and concede that any effect at those amounts is unmeasured.
- After stoppingClinical
The registry records both the phase 2 trial and its extension as terminated on preliminary safety data, with no ACE-031 study registered since. There is no established course, no approved indication and no monitoring framework to describe.
- ACE-031 has no PubChem compound record because it is a protein, not a small molecule. It also has no sequence that can be printed as a peptide: it is a homodimer of the activin receptor type IIB extracellular domain fused to human IgG1 Fc, expressed in mammalian cells, which is why the chemistry card on this page is empty.
- The programme stopped on safety, not on failure to work. The muscle signal was real and fast; the trap also binds BMP-9 and BMP-10, ligands that keep blood vessels quiet, which is the leading explanation offered for the nosebleeds and dilated vessels. No dose has been shown to separate the two effects.
- A 2025 doping-control analysis found that none of 14 products sold online as ACE-031 contained ACE-031; the 12 that contained anything held full-length activin receptor IIB without the Fc region, plus many unrelated proteins. The rows above record what sources report. ACE-031 is prohibited in sport at all times under WADA section S4.3 and is not approved by any regulator.
Sources for this section (10)
- A single ascending-dose study of muscle regulator ACE-031 in healthy volunteers
- A Safety, Tolerability, Pharmacokinetic and Pharmacodynamic Study of ACE-031 (ActRIIB-IgG1) in Healthy Postmenopausal Volunteers (NCT00755638)
- Myostatin inhibitor ACE-031 treatment of ambulatory boys with Duchenne muscular dystrophy: Results of a randomized, placebo-controlled clinical trial
- Study of ACE-031 in Subjects With Duchenne Muscular Dystrophy (NCT01099761)
- Extension Study of ACE-031 in Subjects With Duchenne Muscular Dystrophy (NCT01239758)
- ACE-031, a soluble activin type IIB receptor, increases muscle mass and strength in the common marmoset (Callithrix jacchus)
- Gel Electrophoretic Detection of Black Market ACE-031
Plus 3 community resources (dosing guides, forum threads and vendor write-ups), reported above but not linked.
Overview
ACE-031, also called ramatercept, is a laboratory-built decoy receptor: the outer part of the human activin receptor type IIB joined to the Fc region of human IgG1, designed by Acceleron Pharma to soak up myostatin and the related signals that normally hold muscle growth back. Because it is a dimeric protein of roughly 58 kDa rather than a small molecule or a short peptide, PubChem holds no compound record for it, so this page carries no formula, molar mass, CAS number or structure. A single subcutaneous dose raised lean mass in healthy volunteers, but the phase 2 programme in boys with Duchenne muscular dystrophy was stopped early after nosebleeds and dilated skin vessels appeared; it was never approved anywhere, it is named on the WADA Prohibited List, and a 2025 doping-control analysis of 14 products sold online as ACE-031 found that not one of them actually contained it.
What researchers are exploring
These themes describe recurring questions in published research. They are not claims of effectiveness or recommendations for use.
- 1
Muscle & performance
Androgen receptor modulators, myostatin pathways and exercise-mimetic research.
- 2
Phase 1 single ascending-dose study
Exposure rose in proportion to dose and the mean terminal half-life was 10-15 days, which is the Fc region at work. In the 3 mg/kg group, total body lean mass rose 3.3% on DXA and thigh muscle volume rose 5.1% on MRI.
- 3
Registry record for the phase 1 study
The ClinicalTrials.gov entry for the study above is listed as completed, sponsored by Acceleron Pharma, which the registry now records as a Merck subsidiary. A second phase 1 record, NCT00952887, enrolled 70.
- 4
Phase 2 trial in Duchenne muscular dystrophy, halted
No serious or severe adverse events occurred, but the study was stopped after the second dosing regimen because of epistaxis and telangiectasias, that is nosebleeds and dilated small vessels in the skin. Six-minute.
- 5
Registry record for the halted phase 2 trial
The registry lists this study as terminated, with the reason recorded as being based on preliminary safety data, and an end date of June 2011. A companion extension study, NCT01239758, was terminated on the same.
- 6
Primate study in common marmosets
Lean body mass at the end of dosing was higher than baseline in treated marmosets but not in vehicle controls, biceps brachii fibre cross-sectional area rose in both type I and type II fibres, and extensor digitorum.
What the current evidence can support
Study models remain visible so laboratory and animal findings are not mistaken for established human outcomes.
- Human
Human studies and registrations
4 protocol rows on this page come from human trials, trial registrations, regulator labels or reviews of human data. Approval status and populations are stated per row.
- Animal
Preclinical models
2 protocol rows describe animal, cell or toxicology work. Amounts from these rows do not translate to people.
- Not graded
Community-reported use
3 rows record what blogs, vendor write-ups or forums describe for ACE-031. None has been verified against primary literature.
Identity, limitations and unknowns
Important limitations
- Every amount on this page is a report of what a source describes, not a protocol to follow.
- Preclinical and community rows do not establish a human amount, schedule or route.
- Formulation, purity and presentation vary by supplier and are not covered by the dossier.
Sources
7 curated references, each with its journal, year and study model, plus 3 community resources reported but not linked.
- A single ascending-dose study of muscle regulator ACE-031 in healthy volunteers
- A Safety, Tolerability, Pharmacokinetic and Pharmacodynamic Study of ACE-031 (ActRIIB-IgG1) in Healthy Postmenopausal Volunteers (NCT00755638)
- Myostatin inhibitor ACE-031 treatment of ambulatory boys with Duchenne muscular dystrophy: Results of a randomized, placebo-controlled clinical trial
- Study of ACE-031 in Subjects With Duchenne Muscular Dystrophy (NCT01099761)
- Extension Study of ACE-031 in Subjects With Duchenne Muscular Dystrophy (NCT01239758)
- ACE-031, a soluble activin type IIB receptor, increases muscle mass and strength in the common marmoset (Callithrix jacchus)
- Gel Electrophoretic Detection of Black Market ACE-031