Novo Nordisk Sues Eli Lilly Over Zepbound and Mounjaro Ads, Alleging Omitted GLP-1 Dosing Data

Novo Nordisk announced on July 21, 2026 that it has filed a lawsuit against Eli Lilly and Company and Lilly USA, LLC in the US District Court for the District of New Jersey, alleging that Lilly's nationwide direct-to-consumer advertising for Zepbound (tirzepatide) and Mounjaro (tirzepatide) violates federal and state false-advertising and unfair-competition statutes, including the Lanham Act.^1,2 The complaint contends that Lilly's campaigns mislead people living with obesity and type 2 diabetes by leaving out information about the most effective injectable doses of Wegovy (semaglutide) and Ozempic (semaglutide) currently on the market.³

The suit follows a formal cease-and-desist letter Novo Nordisk sent to Lilly over the advertisements. According to the complaint, Lilly declined to pull the ads down or issue a meaningful correction in response.

Novo Nordisk Inc., headquartered in Plainsboro, New Jersey, is the US affiliate of Novo Nordisk, the Denmark-based drugmaker. The US business has operated for roughly 40 years and employs about 10,000 people across more than 10 manufacturing, research and development, and corporate sites in 7 states and Washington, D.C. Globally, the company employs approximately 67,900 people and markets products in around 170 countries. Eli Lilly, the defendant, is headquartered in Indianapolis.

Zepbound-Wegovy Comparison Omits Newest FDA-Approved Dose

According to the complaint, 1 campaign compares the maximum tolerated dose of Zepbound (10 mg/15 mg) against a lower dose range of Wegovy, 1.7 mg/2.4 mg. The ads do not reference the 7.2 mg dose of injectable Wegovy, which the FDA approved in March 2026.

That approval was supported by the STEP UP trial, a 72-week study of 1407 adults with obesity (BMI of 30 kg/m2 or greater) without diabetes. Participants taking Wegovy 7.2 mg lost an average of 18.8% of body weight (about 47 pounds) compared with 3.9% (about 10 pounds) among those on placebo. The most commonly reported adverse reactions were nausea, vomiting, dysesthesia, constipation, abdominal pain, fatigue, headache, dizziness, hair loss, and flatulence.

Novo Nordisk's complaint also notes that no head-to-head clinical trial has directly compared the highest doses of Zepbound and Wegovy, which the company argues makes the comparative claims especially misleading. The campaign has run during widely viewed sporting broadcasts and on TikTok and Facebook, according to the company.

Mounjaro Ads Skip Newer Ozempic Maintenance Dose

A second campaign compares Mounjaro at its highest available dose, 15 mg, against injectable Ozempic at 1 mg. The complaint states that the FDA approved a higher, 2 mg maintenance dose of Ozempic more than 4 years ago, a dose the ads do not mention.

“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, said in a press release.¹ “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.”

Novo Nordisk is asking the court for a permanent injunction requiring Lilly to remove the disputed advertising from all platforms and to run a corrective campaign. The company has told Lilly that, absent a voluntary withdrawal of the ads, it intends to file a motion in the coming days seeking a preliminary injunction, along with evidence it says shows consumers have been confused and misled, to block the ads immediately.

Is There a Potential Impact on Drug Manufacturing?

The lawsuit is a private Lanham Act and state unfair-competition action, not an FDA enforcement proceeding, and its outcome (an injunction, corrective advertising, damages) would affect Lilly's marketing materials, not the FDA-approved product labels for Zepbound or Mounjaro. The complaint is about promotional omissions, not about what's approved. The doses at issue on both sides, Wegovy 7.2 mg and Ozempic 2 mg, are already FDA-approved and already reflected in each drug's label.^{4, 5}

The lawsuit does reflect the complexity of the GLP-1 market, and there have been regulatory actions involving promotional materials. The FDA's Office of Prescription Drug Promotion sent warning letters to Lilly, Novo Nordisk, and Hims & Hers over misleading GLP-1 promotion, part of a broader White House-directed crackdown that has included roughly 30 letters to telehealth and compounding operators and reported plans for dozens more.⁶ That history may point to a pattern of FDA concern about the category's advertising, even though the FDA isn't a party to this suit.

The impact of the lawsuit may be on the overall market going forward. Lilly may need to revise or pull the disputed ads regardless of how the litigation resolves, because a preliminary-injunction motion could force fast changes; closer FDA/OPDP attention to comparative dosing claims across the GLP-1 class, given the agency is already primed on this issue; and a precedent-setting effect for the category—comparative ads that don't reflect the newest approved doses become higher-risk from a liability standpoint, which could push both companies (and competitors entering the space) toward more conservative, label-aligned comparative.

Because the lawsuit doesn't touch production lines; chemistry, manufacturing, and controls filings; or supply agreements, its direct effect on manufacturing operations is minimal. But it may have a few indirect implications.

Both companies have spent the past 2 years pouring capital into expanding dosing options: Lilly has raised its Lebanon, Indiana investment past $9 billion largely to boost tirzepatide API and fill-finish capacity,⁷ and Novo Nordisk's roughly $16.5 billion Catalent acquisition (plus a related $11 billion site transfer) was explicitly aimed at growing Wegovy and Ozempic output.⁸ Novo's own investor guidance projects semaglutide manufacturing capacity growing about 50% from 2025 to 2027, concentrated specifically in fill-finish for higher-dose pens; the 2.4 mg and 7.2 mg Wegovy strengths and the 2 mg Ozempic pen have historically been the most fill-finish-constrained SKUs in the portfolio. The FDA's declaration that the Wegovy/Ozempic shortage had ended made it possible for these higher doses to be promoted at national scale.⁹ In that sense, the ad war is downstream of a manufacturing race: once fill-finish capacity caught up with demand for the newest, highest-potency doses, competition shifted from “can we make enough” to “whose highest dose wins the comparison.”

The market demand should see continued heavy capital allocation toward high-dose fill-finish and device (multi-dose pen) manufacturing on both sides, because dose strength has become the primary axis of both commercial and now legal competition. Second, this kind of dispute typically pushes companies to tighten internal coordination between manufacturing/supply planning, regulatory affairs, and commercial marketing, so that promotional claims don't reference doses that aren't yet fully available at scale or fail to reflect ones that are. Third, with the FDA already conducting a parallel crackdown on misleading GLP-1 promotion, manufacturers across the category may face more pressure to align launch communications timing with actual manufacturing ramp-up milestones rather than getting ahead of supply. All of this may reinforce dose-strength manufacturing capacity.¹⁰

References

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. An introduction to trademark law in the United States. Congress.gov. Accessed July 21, 2026. https://www.congress.gov/crs-product/IF12456
3. Zubulake Z. New Wegovy dose approved under FDA’s CNPV. PharmTech.com. March 20, 2026. https://www.pharmtech.com/view/new-wegovy-dose-approved-under-fda-s-cnpv
4. Constantino AK. Novo Nordisk sues Eli Lilly, alleging misleading GLP-1 advertising. CNBC. July 21, 2026. https://www.cnbc.com/2026/07/21/novo-nordisk-sues-eli-lilly-glp-1-ads.html
5. Silverman E and Chen E. Novo Nordisk sues Eli Lilly over GLP-1 drug ads it calls ‘deceptive’. STAT. July 21, 2026. https://www.statnews.com/pharmalot/2026/07/21/novo-nordisk-sues-eli-lilly-glp1-drug-ads/
6. Lavery P. Lilly, Novo, Hims get FDA warnings about misleading drug communications. PharmTech.com. September 16, 2025. https://www.pharmtech.com/view/lilly-novo-hims-get-fda-warnings-about-misleading-drug-communications
7. Lilly commits additional $4.5 billion across Indiana manufacturing sites, opens first dedicated genetic medicine facility. Press release. Eli Lilly. May 6, 2026. https://investor.lilly.com/news-releases/news-release-details/lilly-commits-additional-45-billion-across-indiana-manufacturing
8. Novo Holdings completes acquisition of Catalent. Press release. Novo Holdings. December 18, 2026. https://novoholdings.dk/news/novo-holdings-completes-acquisition-of-catalent
9. 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
10. GLP-1 Drug Manufacturing: Expansion & Tech Transfer. Intuition Labs. Accessed July 21, 2026. https://intuitionlabs.ai/articles/glp-1-drug-manufacturing-cdmo-tech-transfer