What is the false advertising fight between Novo and Lilly?
Novo sued Lilly on July 21, 2026 alleging ads compare Zepbound with 1.7 and 2.4mg Wegovy while concealing the 7.2mg dose approved in March 2026 — Lilly says it relies on SURMOUNT-5 data showing 47% less weight loss on 2.4mg Wegovy.
As Lilly overtook Novo in the obesity market, Novo sued Lilly on July 21, 2026 in New Jersey federal court under the Lanham Act. Novo alleges Lilly's ads for Zepbound and Mounjaro compare Lilly's highest doses with lower doses of Wegovy (1.7mg and 2.4mg) while omitting the 7.2mg Wegovy dose approved in March 2026, and that "Lilly knowingly cites outdated clinical trials." Novo says the ads have generated about 700 million impressions and it planned to seek a preliminary injunction. Lilly says its ads rest on SURMOUNT-5, which showed 2.4mg Wegovy produced 47% less relative weight loss than Zepbound, and notes Novo has never tested its highest doses head-to-head. The case shows how comparative claims have replaced supply as the main competitive battleground.