Overweight or obese adults lost more weight and shed pounds faster using Eli Lilly's Mounjaro than those taking Novo Nordisk's popular rival weight loss drug, according to an analysis of health records and other data. Within one year of starting treatment, 42.3% of those taking tirzepatide - the active ingredient in Mounjaro and Zepbound - had lost at least 15% of their weight, compared with 19.3% among patients taking semaglutide - the main ingredient in Wegovy and Ozempic, the study published on medRxiv in advance of peer review found. After accounting for individual risk factors, patients taking Mounjaro were 76% more likely to lose at least 5% of their body weight, more than twice as likely to lose at least 10%, and more than three times as likely to lose at least 15%, compared to patients taking Ozempic, the report said.