Abstract
Obesity affects over 2 billion adults globally, with projections indicating that nearly two-thirds of adults will be affected by 2050. Glucagon-like peptide-1 receptor agonists (GLP-1RAs) have transformed obesity treatment, achieving weight loss previously considered attainable only with bariatric surgery. However, GLP-1-based therapies have revealed important limitations, including weight loss plateaus, substantial inter-individual variability, and weight regain upon discontinuation, underscoring the need for next-generation approaches. Existing reviews have focused predominantly on approved GLP-1RAs, with limited synthesis of emerging multi-receptor agonists, oral formulations, and body composition-targeted agents, while guidance on treatment personalization and sequencing strategies remains limited. This review examines the evolving landscape of obesity pharmacotherapy beyond injectable GLP-1RAs. Oral GLP-1 agonists, including orforglipron, offer comparable efficacy to injectables while potentially improving global accessibility by eliminating cold-chain requirements and simplifying manufacturing. Multi-receptor agonists represent the most transformative developments: triple agonists such as retatrutide achieve weight reductions of 20-24%, while dual GLP-1/glucagon agonists like survodutide and mazdutide show strong efficacy with particular promise for metabolic-associated steatotic liver disease. Maridebart cafraglutide, combining GLP-1 agonism with glucose-dependent insulinotropic polypeptide (GIP) antagonism, enables once-monthly dosing. The amylin pathway has re-emerged through long-acting analogs (cagrilintide, eloralintide) and unimolecular co-agonists (amycretin), achieving weight reductions up to 24% via distinct neuroendocrine circuits. Body composition optimization through agents like bimagrumab addresses lean mass preservation during potent anorectic therapy. Personalized approaches, including setmelanotide for monogenic obesity, exemplify precision pharmacotherapy. Collectively, these advances signal a shift from appetite-centric weight loss toward integrated metabolic, neuroendocrine, and body-composition-focused disease modification. The next epoch of obesity pharmacotherapy will be defined by multi-receptor strategic combinations, targeted approaches to preserve lean mass, and personalized treatment algorithms. Critical priorities include phenotype-stratified trials, long-term safety surveillance, pediatric obesity research, and implementation science to ensure equitable global access. Balancing pharmacologic innovation with sustainable, equitable implementation remains the defining challenge ahead.