Lilly and Novo take GLP-1 copycat fight to advertising review board

Eli Lilly and Novo Nordisk have filed 10 cases combined over the past year with BBB National Programs' National Advertising Division, a self-regulatory body that handles advertising disputes faster than litigation, according to Bloomberg Law ^[1]. The filings add a new front to the two companies' legal campaign against compounded and telehealth-sold versions of their GLP-1 drugs.

Novo has filed 130 federal lawsuits and five challenges with the National Advertising Division, or NAD, a Novo spokesperson said in an email ^[1]. Lilly has filed dozens of federal lawsuits and at least five NAD cases ^[1][2]. Lilly called the division "an independent authority whose mission is to build consumer trust in advertising" ^[1]. The financial stakes are large: Lilly's tirzepatide franchise reached $40 billion in sales and Novo's products generated $35 billion last year ^[1].

"They're using a lot of arsenals," said Alan Minsk, chair of the food and drug practice at Arnall Golden Gregory LLP ^[1]. "These are big bucks for the companies and they're trying to use all of their tools that they've got." ^[1]

How the cases work

The NAD has existed since 1971 and has settled disputes over products from bathroom cleaners to infant formula, but the GLP-1 makers turned to it relatively recently ^[1]. In a challenge, the burden is on the advertiser to show it has a reasonable basis for the claim at issue ^[1]. The division assigns an attorney to review the case, confers with the parties and drafts a decision or recommendation ^[1].

The process is voluntary. An advertiser does not have to take part or follow recommendations, and the NAD holds no legal authority ^[1]. It can escalate a matter to the FDA, the Federal Trade Commission or state attorneys general, and can report an ad to the social media platforms where it ran ^[1]. Decisions can be appealed to a board of academics and brand representatives ^[1].

"The options vary a lot in terms of cost, timeframe to a resolution, and effectiveness," said Ricardo Carvajal, a director at Hyman, Phelps & McNamara P.C. "But at the end of the day, we're talking about a matter of months to get to a final resolution in the form of an NAD case decision." ^[1]

The challenges largely began after the FDA determined that branded GLP-1s were available again following a shortage period, a finding that effectively prohibited mass production of cheaper copies that had been used by at least a million patients ^[1]. Compounders continue to make personalized versions ^[1].

Two decisions so far

In December 2025, Novo's challenge against Willow Health Services led the NAD to find the Texas telehealth company's safety, efficacy and superiority claims for its compounded semaglutide were unsubstantiated ^[2]. Willow did not provide a statement saying whether it would comply, so the NAD referred the matter to the FTC, state attorneys general and the platforms where the ads ran ^[1][2]. Willow later returned to the NAD after discussions with the FTC, and in July 2026 the NAD confirmed the company had permanently discontinued all the challenged claims, covering weight loss support, comparability to FDA-approved semaglutide, and effectiveness without diet or exercise ^[2].

In May 2026, Lilly's challenge against Noom led the NAD to recommend that the company modify or discontinue its "A Smaller Dose. A Smarter Start. Microdose GLP-1Rx Starts at $119" claim ^[2]. The NAD found the claim conveyed an unsupported message that a smaller dose itself provided a measurable health benefit ^[1][2]. Noom disagreed with the conclusion but voluntarily agreed to comply, and separately told the NAD it was permanently discontinuing other challenged claims covering dosing, efficacy and side effects, which the NAD did not review on the merits as a result ^[2].

Why it matters for patients

A decision against a compounded seller is not the same as a government finding that a product is unsafe or illegal. The NAD cannot order a company to stop selling, and a seller can decline to participate or ignore a recommendation ^[1]. The practical consequences are referrals to the FTC, state attorneys general or ad platforms, and removal of the disputed marketing ^[1].

The claims that have been dropped in these cases are specific: comparability to FDA-approved semaglutide, effectiveness without diet or exercise, and a health benefit from smaller "microdoses" ^[2]. People who see those claims on other sites are seeing language that has already been challenged and withdrawn elsewhere. Compounded drugs are not FDA-approved, and ads for them do not get the same government review as brand-name treatments ^[1][2].

The FDA has sent more than 100 warning letters in the last year over misbranded compounded GLP-1 claims, but enforcement has stayed narrow, focused on active ingredients, branding and product performance ^[1][2]. "FDA's warning letters, at least in this space for the telehealth and compounders, have been very narrow," said Dara Katcher Levy, a director at Hyman ^[1]. Ashwin Chetty, a doctor of medicine candidate at Yale School of Medicine who studied compounded GLP-1 ads, said enforcement "has really been focused on what these websites shouldn't say, and that absolutely is needed," but that there should also be guidance on what those websites should say ^[1].

What happens next

Several related matters remain unresolved. Lilly sued six companies, including compounding pharmacies, medical spas and online sellers, in August 2026 over alleged illegal sales of retatrutide, its experimental obesity drug that has not been approved by the FDA ^[2]. In January 2026, Strive Compounding Pharmacy filed a federal antitrust suit in the Western District of Texas against Lilly and Novo, alleging the drugmakers used exclusive agreements with telehealth platforms to bar those platforms from working with compounding pharmacies ^[2]. Outcomes in those cases have not been reported. The number of NAD challenges the companies plan to file next has not been disclosed.