A systematic review and meta-analysis of the efficacy and safety of pharmacological treatments for obesity in adults

This systematic review and network meta-analysis evaluated the efficacy and safety of obesity management medications (OMMs) in terms of reducing body weight and impact on obesity-related complications. Here a Medline and Embase search was performed up to 31 January 2025 for randomized controlled trials comparing OMMs versus placebo/active comparators in adults. Primary endpoint was percentage of total body weight loss (TBWL%) at the end of the study. Secondary endpoints were TBWL% at 1, 2 and ≥3 years, lipid profile, blood pressure, hemoglobin A1c, fasting plasma glucose, mental health, serious adverse events, quality of life, cardiovascular morbidity and mortality, remission of obesity-related complications and all-cause mortality. Fifty-six clinical trials were identified—orlistat (22), semaglutide (14), liraglutide (11), tirzepatide (6), naltrexone/bupropion (5) and phentermine/topiramate (2)—enrolling 60,307 patients (32,598 OMM and 27,709 placebo). All OMMs showed a significantly greater TBWL% versus placebo (P < 0.0001), more than 10% for semaglutide and tirzepatide. Both tirzepatide and semaglutide showed normoglycemia restoration, remission of type 2 diabetes and reduction in hospitalization due to heart failure. Semaglutide was effective in reducing major adverse cardiovascular events and reducing pain in knee osteoarthritis. Tirzepatide was effective in remission of obstructive sleep apnea syndrome and metabolic dysfunction-associated steatohepatitis. These results support the need to individualize the selection of OMMs.