21 July 2026

Novo Nordisk has filed a lawsuit against Eli Lilly and its U.S. subsidiary, Lilly USA, in the U.S. District Court for the District of New Jersey, alleging that the company's advertising campaigns for its obesity and diabetes medicines, Zepbound® (tirzepatide) and Mounjaro® (tirzepatide), violate federal and state false advertising and unfair competition laws.

The Danish pharmaceutical company argues that Lilly's direct-to-consumer advertisements present incomplete and misleading comparisons with Novo Nordisk's products, Wegovy® (semaglutide) and Ozempic® (semaglutide). According to the complaint, the advertisements fail to include information on the latest FDA-approved higher doses of Novo Nordisk's injectable therapies, potentially giving consumers an inaccurate impression of the relative effectiveness of the competing medicines.

Novo Nordisk stated that the legal action follows an unsuccessful attempt to resolve the issue through a formal cease-and-desist request, claiming Lilly declined to withdraw or substantially revise the advertisements.

The lawsuit alleges that Lilly relied on older clinical studies comparing the highest doses of Zepbound with lower doses of Wegovy, while omitting the newer 7.2 mg injectable dose of Wegovy, approved by the U.S. Food and Drug Administration in March 2026. Novo Nordisk maintains that this higher dose demonstrated significant weight-loss benefits and that no direct head-to-head clinical trial has compared the highest approved doses of the two medicines.

The complaint also challenges advertising for Mounjaro, alleging that Lilly compares its highest approved dose with a lower-dose version of Ozempic despite the availability of a higher FDA-approved maintenance dose of Ozempic that has been on the market for several years.

Novo Nordisk further contends that the advertising campaigns, which have appeared during major sporting events and across social media platforms including TikTok and Facebook, have contributed to consumer confusion regarding the comparative performance of the medicines.

Through the lawsuit, Novo Nordisk is seeking a permanent court order requiring Lilly to discontinue the disputed advertisements and launch a corrective advertising campaign. The company has also indicated it may seek a preliminary injunction to halt the campaigns while the case proceeds, arguing that consumers are being misled by the current promotional materials.

The case marks the latest legal dispute between the two pharmaceutical companies as competition intensifies in the rapidly expanding market for GLP-1-based treatments for obesity and type 2 diabetes.