Mitigating loss of lean muscle in GLP-1 and dual GLP-1/GIP agonists: Pipeline opportunities and limitations

Glucagon-like peptide-1 (GLP-1) receptor and dual GLP-1/glucose-dependent insulinotropic polypeptide (GIP) agonists drive significant transformation in the landscape for type 2 diabetes and obesity management, yet 15-40% of weight loss in trials like STEP and SURMOUNT stems from lean muscle mass. This catabolic loss impairs glucose disposal, muscle strength, and physical function; elevating risks for the loss of force generating capacity in the skeletal muscles leading to sarcopenia, particularly in elderly patients. Unfortunately, current FDA guidelines emphasize total weight reduction over body composition, featuring an unmet critical need for elucidating strategies to preserve loss of lean muscle. This review will feature the emerging therapeutics to mitigate loss of lean muscle, including selective androgen receptor modulators, myostatin-targeting TGF-β inhibitors, and gene-silencing siRNA therapies. Despite promising preclinical and early clinical data, limitations persist, including reliance on parenteral biologics, limited mechanistic diversity, short trial durations, and sparse functional outcome data. Future research must prioritize precise muscle assessments, body composition, long-term trials, and accessible interventions integrating pharmacotherapy. These advances could redefine weight loss paradigms, ensuring therapeutic efficacy aligns with optimal body composition and patient outcomes.