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

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.

Work out syringe units with the dosing calculator

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

ACE-031: the short version

Sources

Sources checked: 2026-10-18.

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