The Rising Burden of Obesity and the Emerging Role of Injectable Weight-Loss Therapies: A Systematic Literature Review

Obesity is a growing global health challenge, contributing to increased risk of type 2 diabetes, cardiovascular disease, and premature mortality. Injectable pharmacotherapies, including GLP-1 receptor agonists and dual incretin receptor agonists, have become key interventions for weight management. This systematic literature review evaluates the efficacy and safety of semaglutide, tirzepatide, and liraglutide in adults with overweight or obesity. A comprehensive search of PubMed, Scopus, Web of Science, and Google Scholar from 2015 to 2024 was conducted following PRISMA 2020 guidelines and Cochrane methodology. Twenty-three studies (18 randomized controlled trials, 5 observational studies) were included. Tirzepatide demonstrated the highest mean weight loss (20.1 kg), followed by semaglutide (14.9 kg) and liraglutide (8.4 kg). Gastrointestinal adverse events were the most common, generally mild to moderate, while serious adverse events were uncommon (