Novo Nordisk filed a federal lawsuit against Eli Lilly on July 21, 2026, alleging that Lilly's nationwide direct-to-consumer advertising campaigns for Zepbound and Mounjaro mislead patients by omitting information about the most effective currently available doses of Wegovy and Ozempic. The complaint, filed in the US District Court for the District of New Jersey, alleges violations of the Lanham Act and state false-advertising and unfair-competition statutes.

The lawsuit follows a formal cease-and-desist letter Novo Nordisk sent to Lilly over the disputed ads. According to Novo, Lilly declined to pull the campaigns or issue a correction in response.

In a press release announcing the lawsuit, senior vice president and group general counsel for Novo Nordisk John F. Kuckelman said, “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. 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.”

What the ads say—and what they leave out

At the center of the complaint are two advertising campaigns. The first compares Zepbound at its maximum tolerated dose—10 mg and 15 mg—against a lower dose range of Wegovy, 1.7 mg and 2.4 mg, while making no mention of the 7.2 mg dose of injectable Wegovy that the FDA approved in March 2026. That approval was supported by the STEP UP trial, a 72-week study in which participants taking the higher dose lost an average of 18.8% of their body weight—roughly 47 pounds—compared with 3.9% on placebo. Novo Nordisk's complaint argues that, because no head-to-head trial has directly compared the highest doses of Zepbound and Wegovy, comparative claims that exclude the newer, higher-performing dose are especially misleading. The campaign has aired during nationally televised sporting broadcasts and on TikTok and Facebook.

The second campaign compares Mounjaro at its highest available dose, 15 mg, against injectable Ozempic at 1 mg—without mentioning the 2 mg maintenance dose of Ozempic that the FDA approved more than four years ago.

What is Novo asking the court to do

Novo Nordisk is seeking a permanent injunction requiring Lilly to remove the disputed advertising from all platforms and run a corrective campaign. The company has also notified Lilly that it intends to file a motion for a preliminary injunction in the coming days, accompanied by evidence it says demonstrates that consumers have been confused and misled—a move that could force immediate changes to Lilly's campaigns before the case is resolved.

The broader context

The lawsuit arrives at a moment when the GLP-1 market has shifted from a manufacturing race to a marketing war. The FDA's declaration² that the Wegovy and Ozempic shortage had ended—and the subsequent approval of the higher-dose 7.2 mg Wegovy formulation—made it possible for Novo to promote its most effective doses at national scale for the first time. The legal dispute is, in some ways, a downstream consequence of that shift: once fill-finish capacity caught up with demand for the newest formulations, the competition moved from supply to messaging.

The FDA's Office of Prescription Drug Promotion has already been active in the GLP-1 space, sending warning letters to Lilly, Novo Nordisk, and Hims & Hers over misleading promotional materials as part of a broader crackdown that has included roughly 30 letters to telehealth and compounding operators. That regulatory backdrop adds additional context to a lawsuit that, while a private action rather than an FDA enforcement proceeding, signals the intensity of the commercial rivalry now playing out in the GLP-1 category.

Lilly has not yet publicly responded to the complaint.

Sources

1. Novo Nordisk takes action to stop multiple misleading national GLP-1 advertising campaigns by Eli Lilly. Press Release. Novo Nordisk. July 21, 2026. https://www.novonordisk.com/content/nncorp/global/en/news-and-media/news-and-ir-materials/news-details.html?id=916584
2. FDA declares Wegovy and Ozempic shortage is over and that Novo Nordisk is fully meeting or exceeding nationwide demand for all doses. Novo Nordisk. Press release. February 21, 2025. https://www.prnewswire.com/news-releases/fda-declares-wegovy-and-ozempic-shortage-is-over-and-that-novo-nordisk-is-fully-meeting-or-exceeding-nationwide-demand-for-all-doses-302382370.html