For Weight Loss: Why Do GLP-1 Agonists Work, and How Can We Make Them Work Better?

Glucagon-like peptide 1 receptor agonists (GLP-1RAs) have revolutionized the management of not only type 2 diabetes but also obesity. However, even with rapid therapeutic advances in GLP-1RAs, questions regarding the fundamental principles of GLP-1-mediated weight loss and the enhanced efficacy of next-generation therapies remain. In this comprehensive review article, we first examine the milestones of GLP-1, from its initial discovery and biological characterization to its successful translation into clinical therapy. Furthermore, this review highlights the latest clinical trial data, specifically HbA1c reduction, weight-loss efficacy, and safety profiles, while exploring current pipelines of major pharmaceutical companies. Additionally, we delineate the mechanistic principles underlying the efficacy of GLP-1 single- and multi-receptor agonists and address challenges in mitigating side effects of GLP-1RAs. Finally, we analyze the rapidly evolving landscape of next-generation, incretin-based combination therapies. With an abundance of GLP-1- related therapies already available or in development, we assess how future GLP-1 multi-receptor agonists can achieve enhanced efficacy and how leveraging weight-loss biology, such as set-point theory, can improve therapeutic outcomes.