Weight Loss Wonders, Legal Woes: The Price of GLP-1 Popularity

Whether on an episode of South Park, news broadcasts, or testimonials with targeted ads on social media, it’s almost impossible to avoid being bombarded with information about GLP-1 (glucagon-like peptide-1) antagonist medications (“GLP-1 drugs”). GLP-1 drugs, such as Ozempic, Wegovy, Mounjaro, and Zepbound, which have soared in popularity over the recent years, were originally developed to treat type 2 diabetes, but have expanded into treatment for obesity and sleep apnea. Studies have shown that approximately 12% of Americans have used GLP-1 drugs, with approximately 6% currently using them.

On November 6, 2025, the U.S. government announced an agreement with drug manufacturers Eli Lilly and Novo Nordisk to significantly reduce the costs of GLP-1 for weight-loss drugs, including first-time Medicare coverage for these drugs. While this agreement paves the way for additional patient access to these medications, there is mounting legal scrutiny on multiple fronts. Will there be a price to be paid for the popularity of these drugs?

Product Liability Litigation

While clinical trials and post-market studies have identified several side effects of GLP-1 drugs, plaintiffs in recent lawsuits contend that manufacturers downplayed or failed to disclose certain serious risks, especially:

• Gastroparesis (delayed stomach emptying, possibly leading to severe vomiting or intestinal blockages)
• Vision loss, particularly NAION (non-arteritic anterior ischemic optic neuropathy--a condition of sudden, painless vision loss in one eye caused by a lack of blood flow to the optic nerve), alleged in cases involving semaglutide, Saxenda (liraglutide), and related drugs
• Gallbladder, kidney, psychiatric effects: Additional suits cite allegations of gallstones, kidney injury, and even psychiatric side effects (anxiety, depression), asserting that manufacturers did not fully inform doctors or patients.

Due to substantially similar allegations about GLP-1 drugs and claims of gastrointestinal issues, a large number of individual claims have been centralized in MDL-3094 (“In re: Glucagon-like Peptide-1 Receptor Agonists (GLP-1 RAs) Products Liability Litigation”), pending in the U.S. District Court for the Eastern District of Pennsylvania. The MDL focuses on claims that “defendants knew or should have known that their GLP-1 RA products can cause gastroparesis and other gastrointestinal injuries, whether defendants adequately warned plaintiffs or their prescribing physicians about the alleged dangers of these products, and whether defendants made false, misleading, or incomplete representations regarding the safety of these products.”

Theories of Liability & Key Defenses

Common claims raised in the GLP-1 litigation include failure to warn/inadequate label warnings, fraudulent misrepresentation/marketing, and design defects. Plaintiffs assert that drug labels lacked sufficient warning of risks of gastroparesis or NAION, or that serious symptoms were downplayed. In the MDL, Defendants have raised several defenses, including preemption, arguing that federal law (FDA-approved labeling) preempts certain state law claims and have also filed motions to dismiss on causal and diagnostic grounds, demanding proof of objective diagnostic testing. Expert discovery is to be completed by the end of March 2026. The first bellwether trials are set to take place in mid-2026.

Compounding Pharmacies/Regulatory Challenges

Not only are there claims by patients against the drug manufacturers, but there is also litigation commenced by the drug manufacturers against companies selling compounded or unapproved versions of GLP-1 drugs with added ingredients or for unapproved dosage forms that mimic the approved drugs.

Lawsuits have also been brought against FDA for decisions regarding compounding when shortages are declared (or ended), the removal of drugs from FDA’s shortage list, and whether compounding of certain GLP-1 drugs is lawful under sections 503A and 503B of the Food, Drug, and Cosmetic Act.

Conclusion

Litigation over GLP-1 medications is now in a critical pretrial phase. With almost 3,000 cases centralized in a major MDL, discovery in full swing, expert causation under scrutiny, and regulatory actions supplementing the legal claims, the next few months will be impactful.

Defendants are pressing procedural defenses (preemption, causation, adequacy of warnings) that, if successful, could narrow or curtail many claims. On the other hand, emerging evidence (regulatory and scientific) and public focus on adverse events may strengthen plaintiffs’ warning and failure-to-warn theories. The next 12-18 months — especially the Daubert rulings, early bellwether trials, and regulatory updates — are likely to shape outcomes significantly. We will be keeping an eye on same and anticipate reporting on significant developments as the MDL progresses.