GLP-1 medicines and lean mass
GLP-1 medicines are studied mainly for their effect on body weight. Researchers also ask how much of that weight loss comes from lean mass (muscle and other non-fat tissue), because losing lean mass is a different outcome from losing fat.
What one meta-analysis found
A systematic review and meta-analysis of randomised controlled trials searched PubMed, MEDLINE, the Cochrane Library and CINAHL from their start up to October 2022. It included 36 studies: 21 on GLP-1 receptor agonists and 15 on SGLT2 inhibitors. Populations included people with obesity, type 2 diabetes, type 1 diabetes, and polycystic ovary syndrome.
- For GLP-1 receptor agonists, the pooled estimate was a loss of lean body mass of 1.51 kg (95% confidence interval −2.00 to −1.01 kg).
- Across GLP-1 receptor agonists and SGLT2 inhibitors combined, lean mass accounted for 28% of the overall weight lost (95% confidence interval 22% to 34%).
The authors recommend monitoring body composition during treatment. They also note that combined approaches may help preserve lean mass during weight loss.
Questions to ask of any study on this topic
- How was lean mass measured? The review's sub-group analysis separated studies by measurement technique, so the method matters.
- Which population was studied? Results from people with obesity may differ from results in people with diabetes.
- How long did the trial run, and were there exercise or protein guidance arms?
- Was there a control group, and how many people completed the study?
Your own clinician is the right place to discuss any medicine decision, including questions about muscle health.
Educational content. Not medical advice.