ACE-031: research
An experimental muscle-growth protein whose Duchenne program stopped over bleeding concerns.
Also called: Ramatercept, ACE031, ActRIIB-IgG1, ActRIIB-Fc.
Myostatin pathway · Soluble activin receptor IIB–IgG1 Fc fusion protein.
Four registrations: two published randomized trials, a 70-person multiple-dose trial and an 11-person extension. The last two lack posted results; extension participants overlap the Duchenne trial.
Studies
- Single dose in 48 women. rct, n=48, 48 healthy postmenopausal women aged 45–75. At 3 mg/kg, lean mass rose 3.3% and thigh volume 5.1% at day 29. (source)
- Multiple doses in 70 women. rct, n=70, 70 healthy postmenopausal women. Completed multiple-dose study has no posted results or located full publication. (source)
- Duchenne randomized trial. rct, n=24, 24 ambulant boys with Duchenne muscular dystrophy on stable corticosteroids. Nosebleeds and visible small blood vessels prompted stopping after two dose regimens. (source)
- Duchenne extension, stopped early. open-label, n=11, 11 participants from the core Duchenne study. Extension stopped on preliminary safety data; no results were posted. (source)
- What the receptor binds. in-vitro, Purified receptor domains and signaling assays. The receptor binds several growth signals; it is not a muscle-only myostatin blocker. (source)
- Marmoset muscle study. animal, n=12, 12 healthy common marmosets, six male and six female. Muscle changes in primates do not override the human vascular safety signal. (source)
- Testing 14 online products. in-vitro, n=14, 14 market products sold as ACE-031. None contained ACE-031; 12 contained a different receptor protein. (source)
ACE-031 dosage
Typical reported dose: 100 mcg in each shoulder, one time
- Single-dose lower boundary: 0.02 mg/kg once once, under the skin. Studied in a trial. Studied in: Healthy postmenopausal women aged 45–75. (source)
- Single-dose 1 mg/kg cohort: 1 mg/kg once once, under the skin. Studied in a trial. Studied in: Healthy postmenopausal women aged 45–75. (source)
- Single-dose 3 mg/kg cohort: 3 mg/kg once once, under the skin. Studied in a trial. Studied in: Healthy postmenopausal women aged 45–75. (source)
- Duchenne 0.5 mg/kg: 0.5 mg/kg every four weeks every four weeks, under the skin. Studied in a trial. Studied in: Boys with Duchenne muscular dystrophy on stable steroids. (source)
- Duchenne 1 mg/kg: 1 mg/kg every two weeks every two weeks, under the skin. Studied in a trial. Studied in: Boys with Duchenne muscular dystrophy on stable steroids. (source)
- Reported shoulder test injections: 100 mcg in each shoulder; 200 mcg total one reported test session, into muscle. Reported by users, rare report. Studied in: Adults discussing self-use for muscle growth. (source)
These are doses reported in labels, trials or user reports, not a personal plan. Check the source behind each one.
ACE-031 side effects and risks
Reported side effects
- Nosebleeds: Duchenne: 1/9 at 0.5 mg/kg; 5/9 at 1 mg/kg; 0/6 placebo., moderate. Stop further exposure and contact a clinician; persistent heavy bleeding needs urgent care. (source)
- Visible small blood vessels on skin: Duchenne: 0/9 at 0.5 mg/kg; 5/9 at 1 mg/kg; 0/6 placebo., moderate. A program-stopping vascular signal; seek review if new spots or bleeding occur. (source)
- Injection-site redness: Duchenne: 3/9 at 0.5 mg/kg; 6/9 at 1 mg/kg; 3/6 placebo., mild. Worsening warmth, fever or spreading redness needs assessment. (source)
- Headache: Duchenne: 1/9 at 0.5 mg/kg; 3/9 at 1 mg/kg; 1/6 placebo., mild. Severe headache with weakness, fainting or vision change needs urgent care. (source)
- Pain, warmth and flu-like symptoms after market products: Isolated self reports; rates and actual product identity unknown., moderate. Stop further use and seek care for persistent fever, severe pain or systemic illness. (source)
Stop and get help if
- Nosebleed lasting over 10–15 minutes, heavy bleeding, dizziness or trouble breathing: Stop further exposure and get urgent care; call emergency services for heavy bleeding or fainting.
- Breathing trouble or swelling of the face or tongue after injection: Call emergency services now.
- Fever with worsening painful injection-site swelling: Stop injections and seek urgent assessment.
Who should avoid it
- pregnant: No pregnancy safety data or validated fetal exposure limits; reproductive-age pregnancy was not studied.
- breastfeeding: No breastfeeding or infant-exposure safety data were found.
- tryingToConceive: Activin pathways affect reproduction; human fertility safety and washout remain unknown.
- under18: The pediatric program stopped for vascular safety concerns; community protocols are restricted to adults.
- bleedingDisorder: Nosebleeds and visible small blood vessels stopped the Duchenne study.
- other: A history of hereditary bleeding-vessel disease raises concern with the observed vascular adverse effects.
- other: Severe allergic-reaction history was excluded from the first human trial.
- activeCancer: Healthy-volunteer studies excluded malignancy; safety during active cancer is unknown.
- cancerHistory: Prior malignancy was generally excluded from healthy-volunteer studies.
- surgeryPlanned: Bleeding risk and long exposure matter; the extension excluded planned surgery. No validated washout exists.
- heartCondition: Significant heart disease outside the Duchenne diagnosis was excluded; safety is uncertain.
- kidneyDisease: Significant kidney disease was excluded; no validated dose adjustment exists.
- liverDisease: Significant liver disease was excluded; no validated dose adjustment exists.
- testedAthlete: ACE-031 is prohibited in and out of competition under WADA S4.3.
Interactions
- Anticoagulants: Bleeding risks may add up. This is a precaution from the trial signal, not a measured interaction.
- Antiplatelets and NSAIDs: These drugs can increase bleeding. Combined risk with ACE-031 has not been measured.
- Other activin or myostatin blockers: Overlapping signaling blockade has unknown safety. No human trial validates this stack.
- Erythropoiesis-stimulating drugs: These medicines were excluded in the multiple-dose trial; the clinical interaction is unknown.
Product quality risks
- None of 14 tested market products contained ACE-031; 12 held full-length receptor without the Fc fusion.
- One product contained follistatin and one ipamorelin. The 12 receptor products contained many extra proteins.
- A wrong receptor protein cannot inherit the trial molecule’s dose, activity or 10–15-day half-life.
- No sterility or endotoxin guarantee follows from identity or purity testing.
How ACE-031 works
ACE-031 is a decoy receptor that traps myostatin, activins and related signals before they reach cells. This can increase muscle size. It also affects signals outside muscle, which helps explain concern about blood-vessel changes and bleeding.
- Myostatin / GDF-8 and activins: Traps ligands that normally restrain muscle growth.
- BMP and other TGF-beta family signals: Broad binding can affect tissues beyond muscle; vascular effects are a safety concern.
Half-life: Mean terminal half-life 10–15 days after a single subcutaneous trial dose.
Gaps: No approved label, established clinical-practice protocol or validated bodybuilding schedule was found. The 70-person multiple-dose trial and 11-person extension have no posted results or located full publications. Only the 0.02–3 mg/kg single-dose range and 1/3 mg/kg subgroups were confirmed from accessible primary records. Intermediate single-dose cohorts, per-arm placebo changes and full adverse-event tables remain unverified. Human weekly, daily, alternate-day and intramuscular use lack matching controlled dose data. No safe washout, reproductive safety, organ-disease dose adjustment or interaction rates are established. There is no matched route-and-frequency human ceiling for the reported intramuscular test dose. The proposed alternate-day Reddit schedule lacks a stated route and was not converted into a protocol. Grey-market identity failure makes self-reports and dose comparisons especially unreliable. No representative community prevalence, compound-specific poison-center series or validated storage protocol was found.
Related to ACE-031
- Follistatin-344: Human gene-therapy findings do not establish a dose for follistatin-344 protein vials.
- Ipamorelin: An experimental peptide that triggers growth hormone release.
- Hexarelin: A peptide that releases growth hormone; repeated use can weaken the response.
Sources
- 503B Bulk Drug Substances List, FDA · FDA · 2026
- Bulk Drug Substances Nominated for Use in Compounding Under Section 503A of the Federal Food, Drug, and Cosmetic Act, FDA · FDA · 2026
- Bulk Drug Substances Used in Compounding Under Section 503A of the FD&C Act, FDA · FDA · 2026
- Cellulitis, NHS · NHS · 2026
- Find product information about medicines, Medicines and Healthcare products Regulatory Agency · MHRA · 2026
- Medicines, European Medicines Agency · European Medicines Agency · 2026
- Pyrogen and Endotoxins Testing: Questions and Answers, FDA · 2026
- The 2026 Prohibited List, World Anti-Doping Agency · WADA · 2026
- Therapeutic Goods (Poisons Standard—October 2026) Instrument 2026, Australian Government · Australian Government · 2026
- Anaphylaxis, NHS · NHS · 2023
- Definition of the Term “Biological Product” Final Regulatory Impact Analysis, FDA · 2020
- Australian Register of Therapeutic Goods (ARTG), Therapeutic Goods Administration · TGA
- Mixing, Diluting, or Repackaging Biological Products Outside the Scope of an Approved Biologics License Application Guidance for Industry, FDA
- Nosebleed, NHS
- Search criteria - Drug Product Database online query, Health Canada · Health Canada
Sources checked: 2026-10-18.
Information only, not medical advice. Peptifacts does not sell anything and does not link to sellers.