Limited data exist on impact of semaglutide on lean mass and muscle function. The SEMALEAN study aims to evaluate these parameters in patients with obesity treated with Semaglutide (2.4mg).

This prospective study enrolled 115 patients with obesity between February 2022 and December 2023. Body weight, body composition (measured by DXA) and muscle function (handgrip strength) were assessed at baseline (M0), 7 months (M7), and 12 months (M12).

A total of 106 patients (68.9% female; mean BMI 46.3kg/m²) completed the study. Weight loss was significant, with mean reductions of 10% at M7 and 13% at M12; 59% of patients achieved ≥10% weight loss. Total fat mass decreased by 14% at M7 and 18% at M12, while lean mass initially declined (−3kg at M7) but stabilized thereafter. Handgrip strength improved significantly (+4.5kg at M12), and the prevalence of sarcopenic obesity decreased from 49% at baseline to 33% at M12. Subgroup analyses revealed greater weight and fat mass loss in women, while patients with type 2 diabetes or prior GLP-1 analog use showed attenuated responses. Patients with a history of bariatric surgery exhibited the most pronounced reductions in body composition parameters.

The SEMALEAN study highlights the significant impact of semaglutide 2.4mg on weight loss, fat mass reduction, and muscle function improvement, with preserved lean mass and metabolic efficiency. These findings underscore the importance of a comprehensive approach to obesity management, addressing not only weight loss but also functional and metabolic adaptation.