The Study
Antibody blockade of activin type II receptors preserves skeletal muscle mass and enhances fat loss during GLP-1 receptor agonism
This study looked at how two drugs affected mice that were overweight. It saw that when they gave both drugs, the mice kept more muscle and lost more fat. But this doesn't mean it will work the same way in people — it’s just a first look in mice.
Analysis score
Maximum 72 for a cohort study.
Where the score came from
Scientists tested a drug that makes muscles grow and a weight-loss drug together in obese mice to see if they could lose fat without losing muscle.
Where does this study sit?
Reviews of RCTs (Meta-analyses)
Max 100Randomized Trials
Max 90Reviews of Cohort Studies
Max 85Cohort Studies
Max 72Reviews of Case-Control Studies
Max 63Case-Control Studies
Max 58Cross-Sectional & Case Series
Max 50Expert Opinion
Max 518 / 100
Quality score
Groups of people are followed over time to see who develops an outcome. Strong for identifying risk factors and associations, but cannot prove causation as firmly as RCTs.
Key takeaways
Summary
Based on the study abstract and findings.
- 1Yes — preserving muscle while losing more fat could help people stay stronger and burn more calories long-term, reducing weight regain.
- 2The muscle drug alone made muscles 8–10% bigger and fat 30% smaller.
- 3The weight-loss drug alone lost 10% muscle and 50% fat.
- 4Together, they kept all the muscle and lost 70% fat.
- 5Mice also ran 13% better.
Score breakdown, methodology, conflicts of interest, evidence analysis & raw study data
Publication
Journal
Molecular Metabolism
Year
2024
Authors
Elizabeth Nunn, Natasha Jaiswal, M. Gavin, Kahealani Uehara, Megan Stefkovich, Karima Drareni, Ryan P. Calhoun, Michelle Y. Y. Lee, Corey D. Holman, Joseph A. Baur, Patrick Seale, Paul M. Titchenell
Related Content
Claims (7)
Using a GLP-1 receptor agonist together with a myostatin pathway inhibitor leads to a reduction in body fat and either no change or an increase in lean tissue mass.
Bimagrumab blocks specific proteins called activin A and GDF8 that control the growth and maintenance of muscle and fat tissue.
In obese mice on a restricted diet, treatment with bimagrumab increases lean body mass by 8–10% and decreases fat mass by 30%; when combined with semaglutide, lean mass is maintained and fat mass decreases by 70% over 14 days.
In obese mice, blocking ActRII increases muscle mass even when the Akt1 and Akt2 signaling genes are removed, showing that muscle growth in this case does not require Akt signaling.
In mice made obese by diet, a combination of two drugs called bimagrumab and semaglutide increases their maximum oxygen uptake during exercise by about 13% compared to untreated mice, and this improvement is linked to an increase in muscle mass.
In obese mice treated with semaglutide, bimagrumab prevents a 10% reduction in muscle mass in four specific leg muscles that normally occurs with semaglutide treatment alone.
Not medical advice. For informational purposes only. Always consult a qualified healthcare professional before making health decisions.