Novo Nordisk has filed a lawsuit against Eli Lilly in the US District Court for the District of New Jersey, alleging that the company’s advertising for its obesity and diabetes medicines, Zepbound (tirzepatide) and Mounjaro (tirzepatide), violates federal and state false advertising and unfair competition laws, including the Lanham Act.
The Danish drugmaker claims Lilly’s nationwide direct-to-consumer advertising campaigns present false and materially misleading comparisons by omitting information about the highest approved injectable doses of Novo Nordisk’s medicines, Wegovy (semaglutide) and Ozempic (semaglutide).
According to Novo Nordisk, the lawsuit follows Lilly’s refusal to remove or meaningfully correct the advertisements despite receiving a formal cease-and-desist request from the company.
“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,” he added.
In its complaint, Novo Nordisk alleges that Lilly intentionally selected outdated clinical comparisons to portray its medicines as broadly superior while burying or omitting critical clinical context.
For Zepbound, Novo Nordisk argues that Lilly’s advertisements compare the maximum tolerated doses of Zepbound (10 mg and 15 mg) with lower doses of Wegovy (1.7 mg and 2.4 mg) and do not include the highest approved injectable dose of Wegovy, 7.2 mg, which the FDA approved in March 2026.
Novo Nordisk highlighted data from the STEP UP trial, a 72-week study evaluating the efficacy and safety of once-weekly Wegovy 7.2 mg compared with placebo and Wegovy 2.4 mg as an adjunct to lifestyle intervention in 1,407 adults with obesity without diabetes. At 72 weeks, participants receiving Wegovy 7.2 mg achieved a mean weight loss of approximately 19 per cent or about 47 pounds, compared with 3.9 per cent or about 10 pounds, in the placebo group.
The company also noted that no head-to-head clinical trial has compared the highest approved doses of Zepbound and Wegovy. It further alleged that the advertising campaign, which has aired during recent, widely viewed global sporting broadcasts and on TikTok and Facebook, has caused widespread consumer confusion.
Novo Nordisk also challenged Lilly’s advertising for Mounjaro, stating that it compares the medicine’s highest approved 15 mg dose with the 1 mg dose of Ozempic, despite the FDA having approved a higher, more effective 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 its allegedly misleading comparative advertising across all platforms and conduct a corrective advertising campaign.
Novo Nordisk also said it has informed Lilly that if the advertisements are not voluntarily withdrawn, the company intends to file a formal motion with the court in the coming days seeking a preliminary injunction to immediately block the campaigns, arguing that consumers are being confused and misled by Lilly’s ads.
