South American Sciences · Nov 6, 2026
LOSS OF MUSCLE MASS DURING TREATMENT WITH GLP-1 AGONISTS
By Bomfim BO, Shimasaki KHDC, Vasconcelos JGG et al.
Treatment with glucagon-like peptide-1 receptor agonists promotes weight reduction but may be accompanied by a decrease in lean mass, raising concerns about preserving muscle health. This narrative review aimed to analyze changes in lean and muscle mass during treatment in adults with overweight or obesity, considering their possible functional repercussions and monitoring strategies. Clinical trials, body composition analyses, systematic reviews, and consensus statements identified in scientific sources available online were analyzed. The synthesis indicated that weight loss occurs predominantly through fat reduction, although it may also involve an absolute loss of lean mass. However, this change does not necessarily correspond to an equivalent loss of skeletal muscle, nor does it establish, in isolation, a diagnosis of sarcopenia. The heterogeneity of methods and the limited availability of functional assessments hinder conclusions about long-term muscular effects. Nutritional monitoring, ensuring adequate protein intake, and resistance exercise are relevant strategies for muscle preservation. It is concluded that treatment assessment should integrate body composition, strength, and functionality, especially in vulnerable individuals, and that long-term studies are needed to clarify the clinical relevance of the observed changes.