Ozempic Maker Novo Nordisk Sues Eli Lilly For Deceptive Advertising

Ozempic drugmaker Novo Nordisk sued rival GLP-1 manufacturer Eli Lilly in federal court Tuesday, accusing the company of using “intentionally selected outdated studies” to curate allegedly misleading ad campaigns that exaggerate the efficacy of Lilly’s products.

Novo Nordisk said it filed a lawsuit in New Jersey federal court on Tuesday, accusing Eli Lilly of violating state and federal false advertising and unfair competition laws.

The lawsuit accuses Lilly of a “nationwide pattern of deceptive advertising” that “confuses consumers,” and Novo Nordisk said it chose to sue after Lilly did not pull its ads following a cease-and-desist request.

Novo says an ad campaign crafted by Lilly uses an outdated dose of Novo’s Wegovy to compare it unfavorably to Lilly’s Zepbound, accusing the company of withholding information about a higher dose of Wegovy approved by the Food and Drug Administration in March.

Lilly’s ad comparing Zepbound and Wegovy is “especially misleading because there is no head-to-head clinical trial comparing the highest doses of these two medicines,” Novo says.

Novo also pointed to an ad campaign Lilly ran comparing Ozempic unfavorably with Lilly’s Mounjaro, accusing the campaign of comparing a high dose of Mounjaro to a lower dose of Ozempic, despite a higher dose being FDA approved.

Forbes has reached out to Novo Nordisk and Eli Lilly for comment.

Novo says it is seeking a permanent injunction from the court that would require Lilly to pull its “misleading comparative advertising” campaigns and conduct a “corrective advertising campaign.” If Lilly does not voluntarily pull these ads, Novo says it will seek a preliminary injunction, a temporary court order that would block the ads from airing.

700 million. That’s how many impressions Lilly garnered on its Zepbound ad campaign since it began airing in late April, Novo Nordisk alleged in the lawsuit. Novo says the “breadth” of the advertising campaign is causing “competitive harm” and the “false superiority messages are reaching a large, ever-growing audience of prospective patients.”

Novo Nordisk’s lawsuit cites a study that shows its higher 7.2 milligram dose of Wegovy, approved by the FDA in March, helps patients lose an average of 47 pounds, while one in three participants lost about 62 pounds. Novo’s suit says the trial showed results that are “clinically consistent” with Lilly’s most “methodologically rigorous” trial of Zepbound. Novo’s general counsel John Kuckelman told CNBC it “may have been accurate” for Lilly to boast about Zepbound’s greater efficacy before the 7.2 milligram dose of Wegovy became available, but it is “no longer accurate to say that.” Novo’s suit says Lilly acknowledges a higher dose of Wegovy in a brief footnote in the television ad, but it says the footnote is “ambiguous, confusing, virtually illegible, and wholly inadequate.”

Novo Nordisk and Eli Lilly, chief rivals in the booming GLP-1 industry, have struggled for dominance over the obesity medication market, with Novo’s market share slipping from an early lead. Lilly now captures a greater share of prescriptions, CNN reported in February, and BMO analysts said last year they expected Lilly’s drugs to “continue to take incremental U.S. share from Novo’s” GLP-1 medications. “While Novo had the headstart with approval of semaglutide, we believe that this first mover advantage has waned, with Lilly's tirezepatide taking share rapidly,” the analysts wrote. CNBC reported in February Novo Nordisk was bracing for a 5% to 13% decline in sales and profit for 2026, while Lilly expected about a 25% boost in sales. Earlier this year, Novo Nordisk said it would slash prices on its flagship medications in 2027 as it tries to win over customers.