Novo Nordisk has sued Eli Lilly in a New Jersey federal court, alleging that Lilly’s advertising for its obesity drug Zepbound and diabetes drug Mounjaro is “deliberately false” and misleads consumers about comparative efficacy versus Novo’s Wegovy and Ozempic.

The Danish drugmaker claims Lilly cited outdated trial data to assert superior weight‑loss and blood‑sugar results, and that a tiny disclaimer added after a cease‑and‑desist letter does not cure the deception. John Kuckelman, Novo’s general counsel, said the company received no response to its April demand.

Novo seeks a permanent injunction, corrective advertising, and all profits Lilly earned from the disputed ads. Lilly has not yet filed a defense. The suit underscores the intensifying rivalry as both firms roll out oral weight‑loss pills that could broaden market uptake.

The litigation follows Lilly’s current market lead in both diabetes and obesity injectables, though Novo’s Wegovy pill launched in the US in January, ahead of Lilly’s oral option in April. Analysts say the outcome could shape advertising standards across the booming weight‑loss sector.