Eli Lilly’s television advertisements say Zepbound users lost an average of 50 pounds, compared with 33 pounds for people taking Novo Nordisk’s Wegovy. Novo says the comparison became misleading because it did not account for the newest, higher-dose version of Wegovy.
A federal judge has now refused to stop the advertisements while the lawsuit proceeds.
That is a consequential victory for Lilly in the immediate advertising fight. But it is not a final decision declaring every claim in the campaign lawful or resolving the scientific argument between the companies.
What the ruling exposes is the difficult relationship between clinical-trial evidence, pharmaceutical marketing and the legal burden of proving that an advertisement causes harm.
Where the 50 Pounds Versus 33 Pounds Claim Came From
The central comparison is based on SURMOUNT-5, a randomized, open-label Phase 3b clinical trial sponsored by Eli Lilly and published in The New England Journal of Medicine in May 2025.
The trial enrolled 751 adults with obesity, or overweight with an associated medical condition, who did not have type 2 diabetes.
Participants were assigned to receive the maximum tolerated dose of tirzepatide, marketed as Zepbound, or semaglutide, marketed as Wegovy, over 72 weeks.
The tirzepatide group received 10 or 15 mg, while the semaglutide group received 1.7 or 2.4 mg.
Average weight loss was 20.2% with tirzepatide and 13.7% with semaglutide.
In absolute terms, participants lost approximately 50.3 pounds with Zepbound compared with 33.1 pounds with Wegovy.
These were genuine results from a controlled clinical study. The dispute is not that Lilly invented the numbers.
It is whether advertising those numbers after the treatment landscape changed created a misleading impression about the medicines available to patients.
The trial established that tirzepatide produced greater average weight loss than the semaglutide doses tested in SURMOUNT-5. It did not test every dose that would subsequently become available.
Why Novo Says the Advertisement Leaves Out an Important Dose
The timing of the advertising dispute matters.
On March 19, 2026, the US Food and Drug Administration approved Wegovy HD, a new 7.2 mg once-weekly semaglutide injection for eligible adults requiring additional weight reduction.
The approval was supported by Novo Nordisk’s STEP UP clinical research, which showed greater average weight loss with semaglutide 7.2 mg than with the previously approved 2.4 mg dose.
But SURMOUNT-5 had not included the 7.2 mg dose. It had been conducted before that higher-dose option received FDA approval.
Novo therefore argued that Lilly’s advertising continued to promote a comparison that no longer reflected the full range of approved Wegovy doses.
On April 22, Novo objected directly to Lilly and asked it to stop using the disputed comparison.
Lilly subsequently revised its advertising.
The updated commercial specified that the 33-pound Wegovy result came from doses up to 2.4 mg. Its written disclaimer also stated that Wegovy 7.2 mg had since been approved but was not evaluated in the study.
The revision became an important part of the legal record.
There is a scientific limitation on both sides. The STEP UP trial provides evidence about the newer Wegovy dose, but it was not a direct randomized comparison of Wegovy 7.2 mg against Zepbound.
Consequently, the existing trials do not establish which medicine produces greater average weight loss when Zepbound is compared directly with Wegovy 7.2 mg under the same study conditions.
That distinction is essential when a pharmaceutical advertisement turns a particular clinical-trial result into a broader superiority message.
Why the Judge Refused to Stop Lilly’s Advertisements
On October 26, US District Judge Zahid N. Quraishi denied Novo’s request for a preliminary injunction in the District of New Jersey.
The decision followed an evidentiary hearing conducted on August 27 and 28.
A preliminary injunction is a court order that can temporarily prevent certain conduct before the underlying lawsuit is fully resolved.
To obtain that remedy, Novo needed to satisfy legal requirements including a sufficient showing of likely irreparable harm.
Irreparable harm generally means an injury that cannot adequately be remedied through monetary damages.
Novo argued that Lilly’s advertising threatened future sales, damaged its goodwill and undermined its clinical reputation.
The judge found the evidence insufficient to establish the kind of immediate injury needed for a preliminary injunction.
Lilly introduced prescription-volume evidence indicating that prescriptions for Wegovy and Ozempic remained stable during the April-to-July period when the challenged advertising was running.
Novo also faced questions about its failure to supply evidence connecting the advertisements to measurable or imminent business harm.
The court noted that Novo’s witness had not attempted to determine the alleged harm, despite the company’s ability to conduct market research and assess the value of its goodwill.
The judge further concluded that Novo had not demonstrated why any substantial injury could not be compensated through monetary damages if it eventually prevailed.
That was sufficient to deny the request for immediate relief.
The legal principle is narrower than saying a company must always prove that a misleading advertisement has already cost it money.
Courts can consider several forms of injury, but the party seeking this extraordinary remedy must demonstrate harm that meets the applicable legal standard.
In this case, the judge concluded that Novo had not done so.
The Judge Also Examined Novo’s Advertising History
The ruling contained another significant finding that went beyond the immediate evidence of commercial harm.
Lilly argued that Novo’s previous advertising practices made it inappropriate for Novo to obtain the equitable relief it was requesting.
The argument concerned the legal doctrine known as unclean hands.
Under that doctrine, a court may deny certain equitable remedies when the party seeking them has engaged in closely related improper conduct.
The judge examined Novo’s earlier advertising comparing Ozempic with Lilly’s diabetes drug Trulicity.
After higher doses of Trulicity had been approved, Novo continued using comparative claims derived from the earlier SUSTAIN-7 trial without acknowledging that those newer doses had not been evaluated.
The judge found the similarity to Novo’s present complaint significant.
In the October 26 opinion, he wrote that Novo “turns a blind eye to its own advertising history.”
The court also noted that Novo had stopped the earlier advertisements only days before filing its lawsuit against Lilly.
On this separate ground, the judge indicated that he would also exercise his discretion to deny the preliminary injunction.
That does not establish a final false-advertising judgment against Novo in a separate case.
It demonstrates how a company’s previous marketing conduct can influence a court’s decision about whether it should receive an immediate equitable remedy.
The irony was difficult to ignore. Both companies have used clinical-trial comparisons to compete for patients, and the dispute exposed how each has handled newer doses of rival medicines.
What the Ruling Does and Does Not Decide
There is a distinction between refusing to issue a preliminary injunction and deciding the ultimate merits of a false-advertising lawsuit.
The October 26 opinion addressed Novo’s request to prevent Lilly from continuing the challenged marketing before the case was resolved.
The court did not issue a final judgment resolving whether the advertisements violate the Lanham Act or applicable state law.
However, the judge did express skepticism about Novo’s preliminary case.
He noted that the challenged advertising disclosed the existence of Wegovy 7.2 mg and that the higher dose had not been evaluated in SURMOUNT-5.
He also questioned the strength of Novo’s consumer-confusion evidence and the extent to which its arguments accounted for physicians’ role in prescribing these medicines.
Those observations are meaningful, but they were made at an early procedural stage rather than following a completed trial on the merits.
Novo said it was disappointed with the decision and maintained that the central question of misleading advertising remained unresolved.
Lilly welcomed the ruling and denied wrongdoing.
The immediate consequence is clear: the preliminary injunction was denied, leaving Lilly free from the advertising restriction Novo had requested.
But the order itself does not prevent the underlying legal claims from proceeding through further litigation.
A court can refuse to stop an advertisement without delivering a final verdict on the advertisement itself.
What Patients Should Take From the Zepbound Versus Wegovy Advertising Fight
For patients, the most useful lesson is not which pharmaceutical company won a legal argument about television advertising.
It is how much context a clinical-trial number needs before it becomes meaningful.
An average weight-loss figure does not predict what any particular individual will experience.
Results can vary with treatment dose, baseline weight, duration, adherence, other medical conditions and tolerability.
The 50-pound-versus-33-pound comparison describes the results of SURMOUNT-5 among its studied participants and dose groups.
It should not be interpreted as a universal prediction for every patient taking Zepbound or Wegovy.
Nor does the existence of a higher Wegovy dose automatically establish that it is superior to the Zepbound doses studied.
The newer Wegovy dose has its own evidence and safety considerations. A scientifically defensible comparison requires attention to which treatments were actually studied together.
For patients considering these medicines, practical decisions also depend on approved indications, insurance coverage, cost, contraindications and adverse effects.
Both tirzepatide and semaglutide can cause gastrointestinal side effects, and their prescribing information includes important safety warnings.
Those clinical issues should be discussed with an appropriate healthcare professional rather than resolved through advertising slogans.
The commercial stakes are nevertheless enormous. Lilly and Novo are competing across injectable obesity treatments, diabetes medicines and newer oral formulations.
As Grey Pepper’s analysis of Lilly’s third-quarter results explored, sales growth and pricing pressure are shaping the next stage of that competition.
The companies are also competing to define how oral medicines should be evaluated, an issue examined in our report on indirect comparisons involving Lilly’s and Novo’s oral treatments.
That broader market makes comparative advertising valuable. It also makes accurate descriptions of clinical evidence particularly important.
For Lilly, the October ruling removed the immediate threat of a court order stopping the disputed campaign.
For Novo, it exposed weaknesses in the evidence presented in support of urgent judicial intervention.
For patients, the more enduring issue is whether promotional claims provide enough information to interpret the research behind them.
The advertising contest is about market share. The decision in the examination room should still be about evidence, safety, coverage and individual medical needs.
Sources and Further Reading
- US District Court, District of New Jersey: Novo Nordisk Inc. v. Eli Lilly and Company, Opinion, October 26, 2026, Document 66.
- US Government Publishing Office: Official Court Opinion Record, Civil Action No. 26-9027, October 26, 2026.
- Reuters: US Judge Refuses to Block Eli Lilly Weight-Loss Drug Ads, October 26, 2026.
- PharmaVoice: Court Rejects Novo Bid to Block Lilly Obesity Drug Ads, October 28, 2026.
- US FDA: Approval of Wegovy HD 7.2 mg, March 19, 2026.
- The New England Journal of Medicine: Tirzepatide as Compared with Semaglutide for the Treatment of Obesity, SURMOUNT-5, May 11, 2025.
