Research
Macro partitioning
GLP-1 receptor agonists cause a reduction in lean body mass (25-45% of total weight loss), which may impact mobility and metabolic rate, particularly in older adults or those with sarcopenic obesity.
When you lose weight on GLP-1 medications, you lose both fat and some muscle. About a quarter to half of your total weight loss might be muscle. This can affect your strength and metabolism, especially if you are older. To protect your muscles, focus on eating enough protein and doing resistance exercises (like weight lifting) while on the medication.
GoodQualifiesMEDIUM confidence
Evidence from dual-energy X-ray absorptiometry and MRI sub-studies suggests that 25–45% of total weight loss with semaglutide and tirzepatide may come from reductions in lean body mass... the decline in lean mass may have implications for mobility, metabolic rate, and physical function, particularly in older adults or those with sarcopenic obesity.
Why this rating
Based on DEXA and MRI sub-studies.
Source
The expanding role of GLP-1 receptor agonists: a narrative review of current evidence and future directions
Areesha Moiz et al. · EClinicalMedicine · 2025
narrative_reviewCited 68×
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