Lilly and Novo add advertising-board challenges to their campaign against GLP-1 copycats

Eli Lilly and Novo Nordisk are adding a new tool to their multiyear campaign against unapproved copies of their GLP-1 drugs: challenges filed with BBB National Programs' National Advertising Division (NAD), a private group that resolves advertising disputes faster than a lawsuit can ^[1]. Novo has filed 130 federal lawsuits and five NAD challenges; Lilly has filed dozens of federal lawsuits and at least five NAD challenges ^[1][2].

The NAD has settled advertising disagreements since 1971, covering everything from cleaning products to infant formula, but the two drugmakers only started using it recently ^[1]. Unlike a court case, the burden in an NAD proceeding falls on the company being challenged to show it has a reasonable basis for its claim. The process is voluntary, and companies do not have to follow the NAD's recommendations, but the group can refer cases to the Federal Trade Commission, state attorneys general, or the FDA, and can flag ads to the social media platforms carrying them ^[1].

Two recent cases show how this has played out. Lilly's challenge against Noom targeted its "A Smaller Dose. A Smarter Start" tagline for a compounded GLP-1 product; the NAD found Noom had not adequately supported the claim, and Noom agreed to drop or modify it even though it disagreed with the finding ^[1][2]. Novo's case against Willow Health Services pushed the company to permanently stop making certain safety and efficacy claims about its compounded semaglutide, after the NAD referred the matter to the FTC and state attorneys general when Willow initially did not respond to the recommendations ^[1][2].

The push toward NAD challenges comes as FDA warning letters, more than 100 issued in the past year over misbranded compounded GLP-1 claims, have stayed narrowly focused on issues like active ingredients, branding, and product performance ^[1][2]. Lawyers quoted by Bloomberg Law said that narrow FDA focus is one reason companies are turning to the NAD instead ^[1]. The stakes for Lilly and Novo are large: Lilly's tirzepatide products (Mounjaro and Zepbound) reached $40 billion in sales, and Novo's semaglutide products (Ozempic, Wegovy, Rybelsus) generated $35 billion last year ^[1].

This is one part of a broader legal fight. Novo and Lilly have separately filed suit against FDA compounding rules, and Lilly has sued individual compounding pharmacies, including a New Jersey suit against Empower Clinic Services and an August 2026 suit against six companies over alleged sales of retatrutide, an experimental obesity drug not yet approved by the FDA ^[2]. The fight has also flipped direction at times: in January 2026, Strive Compounding Pharmacy filed a federal antitrust suit against both companies, alleging they used exclusive telehealth agreements to block patients from accessing compounded drugs ^[2].

Why it matters for patients

For people considering or using a compounded GLP-1 product, these actions could mean the marketing claims they see change over time, as companies like Noom and Willow Health Services have agreed to drop or modify statements about dosing, effectiveness, or comparability to FDA-approved drugs ^[1][2]. But the NAD has no legal authority to force compliance, so a company can simply ignore a recommendation, as Willow initially did before the case was referred to regulators ^[1]. That means an ad campaign that gets challenged is not the same as one that gets stopped by the government.

It also matters that FDA warning letters have focused narrowly on what compounded-drug ads should not say, such as false claims about active ingredients, rather than requiring specific disclosures about what they should say, according to a Yale researcher who studied these ads ^[1]. Patients evaluating compounded semaglutide or tirzepatide products may not get complete information through FDA enforcement alone.

What happens next

The NAD process typically takes a matter of months to reach a decision, faster than federal litigation, which can take years ^[1]. Novo's Willow Health Services case shows how a dispute can evolve: it began in December 2025, was referred to the FTC after Willow did not initially comply, and was confirmed resolved in July 2026 after Willow discontinued the claims ^[2]. More NAD challenges and federal lawsuits from both companies are likely as the broader legal fight over compounded GLP-1 drugs continues.