Core Viewpoint - The emergence of GLP-1 receptor agonists, such as Semaglutide developed by Novo Nordisk, marks a new era in safe and effective weight loss, initially intended for type 2 diabetes treatment but showing significant weight reduction effects in non-diabetic patients [2][3]. Group 1: GLP-1 Receptor Agonists - GLP-1 receptor agonists primarily reduce caloric intake, potentially mediated by activating GLP-1 receptors in the central nervous system, leading to significant weight loss [2]. - These drugs are generally considered safe but may cause gastrointestinal side effects, including nausea, vomiting, and diarrhea [2]. - A major challenge with GLP-1 receptor agonists is the difficulty in maintaining weight loss long-term due to metabolic adaptation, which reduces energy expenditure and can lead to weight regain upon discontinuation [2]. Group 2: NN501 Development - A new peptide analog, NN501, developed by researchers from the University of Manchester and Novo Nordisk, shows weight loss effects comparable to Semaglutide but operates through a different mechanism, primarily increasing energy expenditure via sustained fatty acid oxidation rather than reducing food intake [3][5]. - NN501 does not produce significant gastrointestinal side effects or muscle loss, and weight rebound after discontinuation is less pronounced compared to GLP-1 receptor agonists [5][7]. - This new treatment could serve as a viable alternative or complementary therapy for obesity management [7].