Novo Nordisk has filed a lawsuit against Eli Lilly, accusing the drugmaker of running false and misleading advertising campaigns for its blockbuster diabetes and obesity drugs, Zepbound and Mounjaro.

 

The lawsuit, filed in the U.S. District Court for the District of New Jersey, alleges multiple violations of federal and state false advertising and unfair competition laws, including the Lanham Act. 

 

Novo Nordisk claims Lilly's nationwide direct-to-consumer advertising misleads millions of Americans living with obesity and type 2 diabetes by failing to include key information about the most effective injectable doses of Wegovy (semaglutide) and Ozempic (semaglutide).

 

The legal action comes after Novo Nordisk said Lilly refused to remove or meaningfully correct the advertisements despite receiving a formal cease-and-desist request.

 

“As new and more effective treatment options become available, people deserve accurate information that reflects the latest scientific evidence and helps them make informed care decisions," said John F. Kuckelman, senior vice president and Group General Counsel, Novo Nordisk. 

 

"Healthcare companies have a responsibility to keep their public claims accurate and current — ineffective, fine-print disclaimers do not fix the misleading impression created by major national campaigns.”

 

According to the complaint, Lilly's advertising campaigns rely on outdated clinical comparisons that pit the company's highest-dose medicines against lower doses of Novo Nordisk's competing treatments, creating what Novo Nordisk describes as a misleading impression of overall product superiority while omitting critical clinical context.

 

For Zepbound, Novo Nordisk alleges Lilly compares the maximum tolerated dose of 10/15 mg of Zepbound with Wegovy at 1.7/2.4 mg but excludes the highest injectable dose of Wegovy—7.2 mg—which was approved by the FDA in March 2026 and demonstrated an average reduction in body weight of approximately 19% (about 47 pounds). 

 

Novo Nordisk also argues the advertisements fail to disclose that no head-to-head clinical trial has compared the highest doses of the two medicines. The company says the campaign has appeared during major global sporting broadcasts and across TikTok and Facebook, contributing to widespread consumer confusion.

 

Novo Nordisk also challenges Lilly's advertising for Mounjaro, alleging it compares the drug's highest 15 mg dose with a lower 1 mg dose of injectable Ozempic, despite the FDA approving a higher 2 mg maintenance dose of Ozempic® more than four years ago.

 

Through the lawsuit, Novo Nordisk is seeking a permanent injunction requiring Lilly to withdraw the challenged advertisements across all platforms and launch a corrective advertising campaign. 

 

The company also said it has informed Lilly that, unless the advertisements are voluntarily withdrawn, it intends to ask the court in the coming days for a preliminary injunction to immediately halt the campaigns, arguing that consumers are being confused and misled.