ACE-031 (1 mg Vial) Research Reference

Quickstart Highlights

ACE-031 (ramatercept) is a soluble decoy receptor: the extracellular domain of activin receptor type IIB fused to a human IgG1 Fc region, a recombinant protein of about 77 kDa rather than a small peptide. It binds myostatin, activins and GDF11 before they reach muscle and was studied by Acceleron in a Phase 1 trial in healthy women and a Phase 2 trial in Duchenne muscular dystrophy, which was terminated for vascular safety signals. This page presents no dosing schedule. It summarizes the clinical doses, explains why they do not translate to a 1 mg research vial, and records the single research-market figure that exists, as context only.

• Identity: A ~77 kDa recombinant ActRIIB-IgG1 Fc fusion protein (a biologic), not a small peptide; listed here as a 1 mg lyophilized vial.
• Dosing status: No established dosing schedule. Clinical doses ranged from 0.02 to 3 mg/kg (1.4–210 mg per dose for a 70 kg adult); the doses that produced effects or adverse events were 0.5–3 mg/kg, which is 35–210 mg per dose, or 35 to 210 times the entire 1 mg vial. No human data exist at research-market amounts.
• Evidence: Human RCT evidence of high quality at clinical doses (Phase 1, n=48; Phase 2 in DMD, terminated for safety in 2011 and discontinued in 2013), but zero evidence at sub-milligram doses, so confidence in any research-market figure is low.
• Storage: Lyophilized at −20 °C (−4 °F) or 2–8 °C (35.6–46.4 °F) depending on source; avoid freeze–thaw and shaking (protein aggregation); no validated beyond-use date after reconstitution.

Reference Overview

Concise summary of the clinical record; this is a reference, not a regimen.

• Goal: The clinical aim was to increase lean muscle mass by blocking myostatin and activin signaling at the ActRIIB receptor.
• Schedule: No schedule is presented. Clinical trials dosed subcutaneously once every 2–4 weeks for up to 12 weeks; the program was halted in 2011.
• Dose Range: Clinical: 0.02–3 mg/kg single dose (Phase 1) and 0.5 mg/kg every 4 weeks or 1.0 mg/kg every 2 weeks (Phase 2); no validated dose exists at the 1 mg vial scale.
• Evidence: Human RCT evidence of high quality at clinical doses (Phase 1, n=48; Phase 2 in DMD, terminated for safety in 2011 and discontinued in 2013), but zero evidence at sub-milligram doses, so confidence in any research-market figure is low.

Research Dosing Context

What the literature and dosing sources contain, and how it relates to a 1 mg vial; no dose is recommended.

• Phase 1 (Attie 2013): Single ascending subcutaneous doses of 0.02, 0.05, 0.1, 0.3, 1.0 and 3.0 mg/kg in 48 healthy postmenopausal women; exposure was linear with dose and the half-life was 10–15 days.
• Phase 2 (Campbell 2017, NCT01099761): 0.5 mg/kg every 4 weeks or 1.0 mg/kg every 2 weeks for 12 weeks in boys with Duchenne muscular dystrophy; higher planned cohorts were never dosed.
• Scale versus the vial: For a 70 kg adult the doses that produced effects or adverse events were 35–210 mg (0.5–3 mg/kg), so one 1 mg vial is about 0.5% of a single 3 mg/kg dose; the lowest Phase 1 cohort (0.02 mg/kg, about 1.4 mg) showed no effect.
• Research-market figure: One site’s calculator lists 500 mcg subcutaneously twice weekly (1 mg/week, one vial per week) for up to 12 weeks. No other source offers a figure, no rationale is given, and this page does not present it as a schedule or convert it to syringe units.
• Frequency in trials: Every 2–4 weeks, matched to the long half-life; the twice-weekly research-market figure has no pharmacokinetic basis.
• Diluent: Sources disagree: one says sterile water only and use immediately, another uses bacteriostatic water at 5 mg/mL. Fc-fusion proteins are sensitive to agitation, so swirl and never shake.
• Vial size: The Amino Labs listing says 1 mg while the product URL says 10 mg; confirm the label before any calculation.

Storage Instructions

Proper storage preserves product quality and efficacy.

• Lyophilized: −20 °C (−4 °F) or below per one source, 2–8 °C (35.6–46.4 °F) per others; dry, dark and desiccated. Avoid freeze–thaw cycles, which can aggregate the protein.
• Reconstituted: No validated beyond-use date. One source says use immediately and do not store; others refrigerate at 2–8 °C (35.6–46.4 °F) without giving a day count. The 28-day convention for small peptides is unvalidated for a 77 kDa protein.
• Handle gently: swirl to dissolve, never shake, and avoid mechanical stress or agitation during transport.
• Allow vials to reach room temperature before opening to minimize condensation uptake.

Important Notes

Practical considerations for consistency and safety.

• ACE-031 is a biologic (Fc-fusion protein), so handling conventions for small peptides (bacteriostatic water, 28-day refrigerator life, insulin-syringe dosing) are unvalidated for it.
• Never approved in any jurisdiction, including by Health Canada or the FDA; not legally marketed for human use in Canada or the US; sold for research use only.
• Prohibited by WADA (S4, myostatin inhibitors) for tested athletes.
• Clinical development was halted in April 2011 after epistaxis, gingival bleeding and telangiectasias in the DMD trial and formally discontinued in May 2013; the successor compound ACE-083 was also discontinued.
• The vascular adverse events are mechanistic (trapping of BMP9 and BMP10), not formulation artefacts, so they cannot be assumed absent at lower doses; equally, no effect of any kind has been shown at sub-milligram doses.
• Evidence caveat: the clinical trials are well documented but their doses are 35–210 times a 1 mg vial; the 500 mcg twice-weekly figure is a single calculator’s default with no study behind it.
• Dosing sites disagree with the primary literature on Phase 2 doses (0.5 and 1.0 mg/kg per ClinicalTrials.gov versus 1–3 mg/kg or 0.5–2.5 mg/kg on various sites) and on route (one site lists IV; the trials were subcutaneous).
• Standard subcutaneous practice applies to any research injection: use a new sterile syringe each time and dispose in a sharps container, and rotate sites (abdomen, thighs, upper arms) to reduce local irritation.

How This Works

ACE-031 is the extracellular domain of activin receptor type IIB (ActRIIB) fused to the Fc portion of human IgG1. Circulating as a decoy receptor with a 10–15 day half-life, it binds myostatin, activins and GDF11 before they can reach ActRIIB on muscle, removing their brake on muscle growth. In the Phase 1 trial, a single 3 mg/kg dose raised lean body mass by 3.3% and thigh muscle volume by 5.1% within 29 days, with biomarker changes suggesting improved bone and fat metabolism, and exposure rose linearly with dose. The same decoy also traps BMP9 and BMP10, ligands that maintain blood-vessel integrity. That off-target binding produced nosebleeds, gum bleeding and telangiectasias in the Phase 2 Duchenne trial, and the data safety monitoring board stopped dosing in 2011. Both the effects and the adverse events were observed at milligram-per-kilogram doses; nothing is known about the pharmacology of a 1 mg vial in a human adult.

Potential Benefits & Side Effects

Observations from the Phase 1 and Phase 2 clinical literature; none apply to research-market doses.

Potential Benefits:

• Lean body mass +3.3% and thigh muscle volume +5.1% at day 29 after a single 3 mg/kg dose in a Phase 1 trial of 48 healthy postmenopausal women.
• About 1.0 kg of lean mass gained at 3 mg/kg, as reported by dosing sites summarizing the Phase 1 data.
• Serum biomarker changes suggesting improved bone and fat metabolism in Phase 1, with non-significant trends to higher bone mineral density and lower fat mass in the Phase 2 DMD trial.
• A non-significant trend toward preserved 6-minute walk distance in the Phase 2 DMD trial.
• No benefit of any kind has been demonstrated at the sub-milligram doses sold on the research market.

Potential Side Effects:

• Epistaxis (nosebleeds), telangiectasias and gingival bleeding: the vascular signals that stopped the Phase 2 trial, attributed to off-target trapping of BMP9 and BMP10.
• Injection-site erythema (Phase 1).
• Headache, reported by one dosing site.
• Phase 2 reported no serious or severe adverse events, yet the data safety monitoring board stopped dosing after the second regimen.
• Unknown risks at any dose outside the trials; no long-term human safety data.

Lifestyle Factors

Complementary strategies for lean-mass goals, which stand on their own evidence.

• Progressive resistance training (2–3 sessions per week) is the evidence-based route to lean-mass gain and the context in which all myostatin-pathway research is interpreted.
• Spread adequate protein intake across meals and keep overall energy intake sufficient to support muscle protein synthesis.
• Sleep 7–9 hours; recovery and anabolic hormone release depend on it.
• Track lean mass with consistent measurements (circumference, photographs or DXA where available) rather than scale weight alone.
• Anyone who notices nosebleeds, gum bleeding or new small visible vessels during any myostatin-pathway research should stop and seek medical review, since these were the dose-limiting signals in the trials.

Recommended Source

We recommend Amino Labs for high-purity ACE-031 (1 mg vials).

Note: Product availability and specifications subject to change. Verify current product details on supplier website.

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