Novo Nordisk seeks court order to stop Lilly's Zepbound and Mounjaro ads

Novo Nordisk told a federal court on July 24 that it wants Eli Lilly's Zepbound and Mounjaro commercials taken down while the two companies litigate whether those advertisements mislead viewers ^[1][2]. The step came three days after Novo sued Lilly in New Jersey, accusing it of false advertising and unfair competition ^[1][2].

Novo's lawyers notified the court that they will formally request a preliminary injunction on Aug. 17 ^[2]. If granted, the order would reach only the Lilly advertisements that make the comparisons Novo objects to ^[2].

Two claims sit at the center of the case. Lilly's ads say Zepbound produces "significantly more" weight loss than Wegovy, and that Mounjaro reduces A1C "significantly more" than Ozempic ^[2]. Novo argues both statements draw on trials that newer, higher-dose versions of its own medicines have left behind ^[1][2].

Those trials are SURMOUNT-5 and SURPASS-2. SURMOUNT-5 matched Zepbound at 10 mg and 15 mg against Wegovy at 1.7 mg and 2.4 mg ^[2]. Wegovy won FDA approval at a 7.2-mg dose in March 2026, which Novo calls its most effective dose and says makes the earlier comparison stale ^[2]. SURPASS-2, run in 2021, pitted Mounjaro's top 15-mg dose against 1 mg of Ozempic; the FDA cleared a 2-mg Ozempic dose the following year ^[2].

In its court papers, Novo said the Zepbound campaign expanded onto social media and generated roughly 700 million impressions beginning in April 2026, and that consumer surveys found more than 30% of people who saw the ad came away believing Zepbound causes substantially greater weight loss than Wegovy ^[2]. Novo also said Lilly turned down a cease-and-desist letter sent in April ^[2]. Lilly has since added small-print language to the Zepbound ad noting that a higher Wegovy dose has "since been approved" ^[2].

Lilly rejected the allegations, saying it stands behind its advertising and will "oppose this motion vigorously" ^[1][2]. A spokesperson said SURMOUNT-5 and SURPASS-2 are "the only head-to-head, randomized clinical trials directly comparing tirzepatide and semaglutide" ^[2]. The same spokesperson said Novo "has never tested its highest doses of semaglutide against Lilly's tirzepatide medicines in any clinical trial" and is using litigation to press comparisons it never put to the test ^[1][2].

John F. Kuckelman, Novo's general counsel, said the campaigns "selectively compare lower doses of Novo Nordisk's medicines against higher doses of Lilly's medicines, based on outdated studies," leaving patients with the mistaken impression that Lilly's drugs are vastly superior ^[2].

Reuters reported that the two companies are competing for a U.S. obesity drug market that analysts expect to be worth more than $100 billion by the end of the decade ^[1]. In the first quarter, Mounjaro sales reached $8.7 billion against about $4.2 billion for Ozempic, and Zepbound ranked fourth among brands in estimated national linear television ad spending in the second quarter at $67.8 million ^[2].

Why it matters for patients

The argument is about which doses the commercials compare, not about whether these medicines are approved. Novo contends the ads withhold information about higher-dose products now on the market; Lilly counters that the studies it cites are the only head-to-head randomized trials that exist between the two molecules ^[1][2].

Neither company has described a trial testing the highest approved doses of semaglutide against tirzepatide, and Novo has not said publicly that one is planned ^[1][2]. No change to FDA-approved labeling, insurance coverage or pharmacy supply has been reported in connection with the case ^[1][2].

What happens next

Novo intends to file its injunction motion on Aug. 17 ^[2]. No date for a court ruling on that request has been reported ^[1][2]. The underlying lawsuit also seeks a permanent order requiring Lilly to withdraw the campaigns and run corrective advertising ^[1].