Eli Lilly's tirzepatide (Mounjaro) outperformed semaglutide in the SURMOUNT-5 trial, with participants losing 20.2% weight vs 13.7% on semaglutide at 72 weeks. 64.6% achieved over 15% weight loss on tirzepatide. Results were shared at ECO 2025 and published in The New England Journal of Medicine.