In a small study of boys with Duchenne muscular dystrophy, a drug called ACE-031 showed a hint of increasing muscle mass, decreasing fat, and improving bone density, but the results were not statistically reliable and the study ended early.
See the scientific wording
Subcutaneous administration of the myostatin inhibitor ACE-031 to ambulatory boys with Duchenne muscular dystrophy at doses up to 1 mg/kg every 2-4 weeks resulted in a non-significant trend toward pharmacodynamic effects on lean mass, fat mass, and bone mineral density, but the study was limited by early termination.
Strong evidence
Randomized trialsOne moderate-quality study supports this claim, so treat this as an early signal rather than settled science.
What the research says
1 study reviewedSupporting (1)
Randomized Controlled TrialHuman2017
The study gave boys the drug and saw small hints of muscle and bone improvement, but the results weren't strong enough to be sure, and the study had to stop early because of side effects, just like the claim says.
Contradicting (0)
No contradicting studies found yet
That doesn't mean it's settled — it just means no study has tested the opposite.
Quality-weighted scoring: we follow the GRADE framework — each study is rated High, Moderate, Low, or Very Low based on study design, methodology rigor, and risk of bias. A single high-quality RCT can outweigh several weaker observational studies.
Scores reflect study quality, not just count.
ACE-031 is a protein that grabs onto myostatin and similar signals in the blood. Myostatin normally tells muscles to stop growing. When ACE-031 binds myostatin, myostatin cannot reach muscle cells. This removes the brake on muscle growth, so muscles can make more protein and get bigger. At the same time, this signal change also affects fat and bone: it reduces fat storage and increases bone density. In boys with Duchenne muscular dystrophy, these effects were small and not strong enough to be certain, and the study was stopped early because of side effects.
Score breakdown, mechanism chain, raw evidence, ideal studies needed & 1 supporting study
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In a small study of boys with Duchenne muscular dystrophy, a drug called ACE-031 showed a hint of increasing muscle mass, decreasing fat, and improving bone density, but the results were not statistically reliable and the study ended early.
Mechanism
1 studyACE-031 works by grabbing myostatin, a protein that normally stops muscles from growing. When myostatin is blocked, muscles get the signal to grow bigger, and this also reduces fat and strengthens bones. However, in the study, the improvements were too small to be sure they were real, and the study had to stop early due to side effects.
ACE-031 is a protein that grabs onto myostatin and similar signals in the blood. Myostatin normally tells muscles to stop growing. When ACE-031 binds myostatin, myostatin cannot reach muscle cells. This removes the brake on muscle growth, so muscles can make more protein and get bigger. At the same time, this signal change also affects fat and bone: it reduces fat storage and increases bone density. In boys with Duchenne muscular dystrophy, these effects were small and not strong enough to be certain, and the study was stopped early because of side effects.
ACE-031 binds to myostatin and related ligands (activin A, GDF-11) in the circulation and extracellular space, preventing them from interacting with native activin receptors.
Blockade of ligand binding prevents activation of activin receptor type IIB (ActRIIB) on muscle and other cells.
Reduced ActRIIB signaling decreases phosphorylation of Smad2 and Smad3, relieving the negative regulation of muscle growth pathways.
Increased muscle protein synthesis and myogenesis lead to gains in lean body mass and potential improvement in muscle function.
Altered growth factor signaling secondary to myostatin inhibition reduces adiposity and increases bone mineral density.
Evidence from Studies
Supporting (1)
Community contributions welcome
Myostatin inhibitor ACE‐031 treatment of ambulatory boys with Duchenne muscular dystrophy: Results of a randomized, placebo‐controlled clinical trial
The study gave boys the drug and saw small hints of muscle and bone improvement, but the results weren't strong enough to be sure, and the study had to stop early because of side effects, just like the claim says.
Contradicting (0)
Community contributions welcome
Score Breakdown
No multi-axis breakdown available yet. The overall Pro / Against score above is the best signal.
- No clinical evidence is available; the score reflects mechanistic plausibility only.
What Would Prove This
Per GRADE and EBM methodology, here is what ideal scientific evidence would look like to definitively prove or disprove this claim, ordered from strongest to weakest.
Systematic Review and Meta-Analysis of Myostatin Inhibitors for Duchenne Muscular Dystrophy
Comprehensive literature search for randomized controlled trials and controlled clinical trials of myostatin inhibitors (including ACE-031) in boys with DMD, with meta-analysis of outcomes including lean mass, fat mass, and bone mineral density.
Double-Blind Placebo-Controlled RCT of ACE-031 in Ambulatory Boys with Duchenne Muscular Dystrophy
Randomized, double-blind, placebo-controlled trial in ambulatory boys with DMD (ages 5-15), with subcutaneous ACE-031 (1 mg/kg every 4 weeks) vs placebo for 12 months. Primary outcomes: change in lean body mass (DEXA), fat mass, and bone mineral density. Secondary: functional outcomes and safety. Adequate sample size for 80% power.
Long-Term Cohort Study of ACE-031 Treated Boys with DMD: Bone Density and Lean Mass Outcomes
Prospective cohort of ambulatory boys with DMD receiving ACE-031 (dose per protocol) followed for 24 months, with DEXA scans at baseline, 12, and 24 months. Comparator: matched cohort receiving standard care. Outcomes: change in bone mineral density Z-scores, lean mass, and incidence of fractures.
Case-Control Study: Lean Mass and Fat Mass in ACE-031 Treated vs Untreated DMD Patients
Retrospective case-control study: cases = boys with DMD who received at least 6 months of ACE-031; controls = matched (age, baseline BMI, steroid use) DMD patients not receiving the drug. Outcome: difference in lean mass and fat mass from DEXA scans. Data from clinical records.
In Vitro Study of ACE-031 Effect on Myoblast Differentiation and Adipogenesis
Primary human myoblasts and adipocyte precursors treated with ACE-031 at varying concentrations. Measure: myotube fusion index, myosin heavy chain expression, lipid accumulation, and markers of myostatin pathway inhibition.