The Study
OR09-08 Muscle Loss With Weight Loss Is Modulated by Age, Sex, and Protein Intake and May Affect Glucose Homeostasis in Adults With Obesity
This study looked at people who were already taking a weight-loss medicine or trying to lose weight with diet, and noticed that those who lost more muscle tended to be older, female, or ate less protein. But it didn’t make people take the medicine—it just watched what happened. So we can’t say the medicine caused the muscle loss, only that it happened together.
Analysis score
Maximum 72 for a cohort study.
Where the score came from
When people with obesity take semaglutide to lose weight, they often lose nearly half their weight as muscle and bone — not just fat.
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 554 / 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.
- 1Losing muscle while losing weight may make it harder to control blood sugar and could weaken bones over time, even if the scale goes down.
- 2Half (47.5%) of weight lost on semaglutide was muscle/bone; older people, women, and those eating less protein lost more muscle; more muscle loss meant worse blood sugar control.
Score breakdown, methodology, conflicts of interest, evidence analysis & raw study data
Publication
Journal
Journal of the Endocrine Society
Year
2025
Authors
Melanie S Haines, L. Dichtel, Caitlin C Dobbie, Samantha Wasserman, Abeer Bader, Megan Mirgorodsky, Chika V Anekwe, G. Curtis, W. P. Dutton, G. O'brien, F. C. Stanford, K. Miller
Related Content
Claims (6)
Among adults with obesity, those using semaglutide lose a greater percentage of their weight from lean tissue (47.5%) than those using only diet and lifestyle changes (34.8%).
In adults with obesity taking semaglutide, those who lose more muscle mass over three months tend to have lower protein intake, are older, or are female, and also show less improvement in blood sugar control.
In adults with obesity taking semaglutide, greater loss of lean mass is linked to increased bone breakdown (measured by CTX) and higher overall bone density, while bone formation (measured by P1NP) remains unchanged.
In adults with obesity, losing weight with semaglutide is less closely tied to losing muscle mass compared to losing weight with diet and lifestyle changes alone.
Among adults with obesity losing weight with semaglutide, those who consume more protein lose less muscle mass than those who consume less protein.
When people lose weight using GLP-1 agonists, about half of the weight lost comes from muscle and bone tissue.
Not medical advice. For informational purposes only. Always consult a qualified healthcare professional before making health decisions.