The Mounjaro lawsuit landscape continues to evolve rapidly in 2026. MDL 3094 — formally known as In re: GLP-1 RAs Products Liability Litigation — now has 4,022 pending actions as of September 1, 2026, before Judge Karen S. Marston in the Eastern District of Pennsylvania. That figure represents a near-doubling from the 1,809 cases recorded in May 2025 and a jump from 3,063 in January 2026, signaling that this litigation is accelerating, not plateauing. With a critical Rule 702 hearing scheduled for September 10 through 18, 2026, no bellwether trial date on the calendar, and no settlement announced, the next ruling from Judge Marston could either reshape or effectively end thousands of claims. Here is what injured patients and their families need to understand right now.
MDL 3094 Case-Count Milestone: What 4,022 Cases Means for Plaintiffs
MDL 3094 consolidates product liability claims against Eli Lilly, the sole defendant for tirzepatide-based injuries. Both Mounjaro — FDA-approved for type 2 diabetes in 2022 — and Zepbound — FDA-approved for weight management in 2023 — contain the same active molecule, tirzepatide. Plaintiffs across both drug brands allege that Eli Lilly failed to adequately warn prescribers and patients about the risk of severe gastrointestinal injuries, including gastroparesis (stomach paralysis), ileus, and bowel obstruction.
The pace of new filings reflects the scale of public exposure. Mounjaro and Zepbound together generated $24.8 billion in revenue in just the first nine months of 2025, accounting for 54% of Eli Lilly’s total company revenue. That commercial dominance — built on tens of millions of prescriptions — is now the backdrop against which thousands of injured plaintiffs are seeking accountability. The federal court caseload statistics from uscourts.gov underscore how unusual it is for an MDL to more than double in under 16 months, placing this litigation among the most rapidly growing pharmaceutical mass torts in recent memory.
Important to note: compounded versions of tirzepatide purchased through telehealth platforms or compounding pharmacies are not eligible for inclusion in MDL 3094. Only patients who used FDA-approved Mounjaro or Zepbound manufactured by Eli Lilly may qualify as plaintiffs in this litigation. As of September 1, 2026, no settlement has been announced in MDL 3094, no class has been certified, and there is no claim form available.
The Rule 702 Hearing: The Most Consequential Pending Decision
No proceeding in the Mounjaro lawsuit carries higher stakes than the Rule 702 hearing scheduled for September 10 through 18, 2026. Under Daubert v. Merrell Dow Pharmaceuticals and Federal Rule of Evidence 702, federal judges serve as gatekeepers for scientific testimony — if Judge Marston rules that plaintiffs’ experts cannot reliably establish medical causation, thousands of cases could be dismissed before a single trial takes place. Eli Lilly has sought to exclude plaintiffs’ expert witnesses and, by extension, to dismiss entire categories of claims.
Daubert hearings in the broader GLP-1 MDL began in May 2025. Case Management Order No. 30, entered in January 2026, drove subsequent expert disclosures and Daubert briefing. Expert depositions concluded by the March 27, 2026 deadline, and summary judgment motions were filed by April 16, 2026. As of September 2026, no formal bellwether trial date has been set — meaning the outcome of the September Rule 702 hearing will dictate the litigation’s entire trajectory. Eli Lilly also raises a preemption defense, arguing that because Mounjaro’s labeling was approved by the FDA, state-law failure-to-warn claims are barred. That argument, if accepted, would be equally dispositive.
The hearing’s outcome is not merely procedural. A ruling favorable to plaintiffs would validate the scientific basis of their claims and put significant pressure on Eli Lilly to begin settlement discussions. A ruling favorable to Eli Lilly could effectively end the litigation for thousands of claimants. Observers across the plaintiffs’ bar are watching the September 2026 proceedings as one of the most consequential events in GLP-1 mass tort litigation to date.
Key Mounjaro Lawsuit Statistics at a Glance
- 4,022 pending actions in MDL 3094 as of September 1, 2026
- 216 lawsuits within the MDL specifically alleging that GLP-1 products like Mounjaro may increase the risk of NAION (nonarteritic anterior ischemic optic neuropathy)
- September 10–18, 2026: Rule 702 hearing scheduled before Judge Karen S. Marston
- No settlement announced, no class certified, and no claim form available as of September 2026
- $24.8 billion in combined Mounjaro and Zepbound revenue in the first nine months of 2025
- MDL case count has more than doubled since May 2025, when 1,809 cases were pending
The Medicare Deal, FDA Label Changes, and a Growing Plaintiff Pool
Two significant developments outside the courtroom are shaping the future size and composition of MDL 3094. First, the Medicare pricing agreement reached under the Inflation Reduction Act is expected to dramatically expand patient access to tirzepatide-based medications. As millions of Medicare beneficiaries — many of them older adults with existing comorbidities — gain access to Mounjaro and Zepbound at reduced cost, the population of individuals potentially exposed to the drug’s gastrointestinal risks will grow substantially. Plaintiffs’ attorneys anticipate that the resulting wave of adverse events could fuel continued MDL growth well into 2027.
Second, the FDA’s December 2025 label update for GLP-1 receptor agonists added new safety language regarding gastrointestinal risks, which plaintiffs argue constitutes an implicit acknowledgment that prior labeling was inadequate. Defendants counter that the updated label was a routine pharmacovigilance measure and does not concede any failure to warn. Regardless of how courts ultimately interpret the label change, it has unquestionably become a central exhibit in expert reports filed ahead of the September 2026 Rule 702 hearing.
Adding further regulatory complexity, on April 30, 2026, the FDA published a proposed determination that semaglutide, tirzepatide, and liraglutide do not meet the statutory criteria for inclusion on the 503B Bulks List. If finalized, this determination would restrict compounding pharmacies from producing these drugs in bulk, effectively channeling more patients toward FDA-approved branded products — and potentially expanding the pool of future MDL plaintiffs who used manufacturer-produced tirzepatide rather than compounded alternatives.
How to Qualify Under Judge Marston’s Gastric Emptying Study Requirement
One of the most significant case management decisions Judge Marston has issued governs which plaintiffs may remain in MDL 3094. Her order requires that gastroparesis claimants produce objective medical evidence of delayed gastric emptying — typically a gastric emptying study, also known as a gastric emptying scintigraphy — to substantiate their injury. Plaintiffs who allege gastroparesis but cannot produce such a study face dismissal from the MDL, regardless of the severity of their symptoms.
This requirement has had a significant screening effect. Attorneys filing new cases in 2026 are advising clients to obtain gastric emptying studies before filing wherever possible, and to request that their treating physicians document the study results in the medical record with specificity. Plaintiffs alleging ileus or bowel obstruction — injuries that do not require a gastric emptying study for diagnosis — are not subject to the same documentation hurdle, though they must still produce medical records confirming the injury and its temporal relationship to tirzepatide use.
Prospective plaintiffs should also be aware of applicable statutes of limitations. Most states impose a two- to three-year window from the date of injury or discovery of injury within which a product liability claim must be filed. Given that Mounjaro received FDA approval in 2022 and Zepbound in 2023, some early users may be approaching or have already passed the limitations deadline in certain jurisdictions. Consulting with a qualified mass tort attorney as early as possible remains critical.
Vision-Loss, Antitrust, and the Expanding Legal Frontier
The gastrointestinal injury claims at the core of MDL 3094 are not the only legal frontier opening up around GLP-1 medications. As of September 1, 2026, there are 216 lawsuits within MDL 3094 specifically focused on whether GLP-1 products like Mounjaro may increase the risk of NAION — nonarteritic anterior ischemic optic neuropathy, a form of vision loss caused by reduced blood flow to the optic nerve. These cases were consolidated into the MDL after early studies raised preliminary concerns about a possible association between GLP-1 receptor agonist use and NAION risk. The scientific record on this question remains actively contested, and it is expected to be a subject of significant expert testimony during the September 2026 Rule 702 proceedings.
Separately, antitrust litigation has emerged targeting the pricing and market conduct of GLP-1 manufacturers, including claims related to pay-for-delay agreements and alleged efforts to suppress competition from generic and compounded alternatives. While these antitrust claims are proceeding in separate proceedings and do not directly affect the product liability plaintiffs in MDL 3094, they reflect the breadth of legal scrutiny now trained on the GLP-1 drug category as a whole.
The intersection of these parallel legal tracks — product liability, vision loss, and antitrust — means that the overall legal landscape surrounding Mounjaro and tirzepatide in 2026 is considerably more complex than a single MDL statistic conveys. For injured plaintiffs, the most immediate and consequential development remains the September 2026 Rule 702 hearing and whatever ruling Judge Marston issues in its aftermath.
Frequently Asked Questions About the Mounjaro Lawsuit
What injuries qualify for inclusion in the Mounjaro lawsuit MDL?
MDL 3094 currently encompasses claims involving gastrointestinal injuries alleged to be caused by tirzepatide, the active ingredient in both Mounjaro and Zepbound. The primary qualifying injuries are gastroparesis (stomach paralysis), ileus, and bowel obstruction. Plaintiffs alleging gastroparesis must provide objective medical documentation, typically a gastric emptying study, as required by Judge Marston’s case management orders. Additionally, 216 lawsuits within the MDL involve claims that GLP-1 products may cause NAION, a serious vision-loss condition. Only patients who used FDA-approved, Eli Lilly-manufactured Mounjaro or Zepbound are eligible — users of compounded tirzepatide from pharmacies or telehealth platforms do not qualify.
What is the current status of the Rule 702 hearing in MDL 3094?
A Rule 702 (Daubert) hearing is scheduled for September 10 through 18, 2026, before Judge Karen S. Marston in the Eastern District of Pennsylvania. The hearing will determine whether plaintiffs’ expert witnesses can offer admissible testimony on medical causation — specifically, whether tirzepatide can cause the gastrointestinal and other injuries alleged. If Judge Marston excludes plaintiffs’ experts, thousands of cases could be dismissed. If she allows the experts to testify, the litigation advances toward potential bellwether trials and, eventually, settlement negotiations. As of September 2026, no settlement has been announced and no trial date has been set.
How much could a Mounjaro lawsuit settlement be worth?
No settlement has been announced in MDL 3094 as of September 2026, and it would be premature to project specific settlement values before the Rule 702 hearing concludes and bellwether trials are scheduled. In comparable pharmaceutical mass torts, individual settlement amounts have ranged from tens of thousands to several hundred thousand dollars depending on injury severity, duration of drug use, medical expenses, lost wages, and other damages. Cases involving permanent injuries — such as long-term gastroparesis requiring surgical intervention, or permanent vision loss from NAION — typically command higher individual values. Plaintiffs should discuss the specific facts of their case with a qualified attorney rather than relying on generalized projections.
How does the 2026 Medicare deal affect the Mounjaro lawsuit?
The Medicare pricing agreement is expected to significantly expand access to tirzepatide-based medications among older Americans, potentially exposing millions of additional patients to the drug. From a litigation standpoint, this means the pool of individuals who may experience adverse events — and who may qualify as future plaintiffs — is likely to grow substantially in 2026 and beyond. It also means Eli Lilly’s financial exposure could increase as total patient volume rises, a factor that may eventually influence the company’s willingness to negotiate settlements. In the near term, however, the most immediate effect on existing plaintiffs is the acceleration of new case filings, which has already pushed MDL 3094 to 4,022 pending actions as of September 1, 2026.
Does the December 2025 FDA label update help plaintiffs in the Mounjaro lawsuit?
The December 2025 FDA label update, which added new safety language regarding gastrointestinal risks associated with GLP-1 receptor agonists, has become a significant piece of evidence in MDL 3094. Plaintiffs argue that the updated label demonstrates that the prior labeling was inadequate and that Eli Lilly knew or should have known about these risks earlier. Defendants counter that routine label updates do not constitute admissions of prior inadequacy and that the FDA’s original labeling met all applicable standards. Judge Marston’s ruling on Eli Lilly’s preemption defense — which argues that FDA approval of the original label bars state-law failure-to-warn claims — will be critical in determining how much weight the December 2025 update ultimately carries in this litigation.
Victoria Chambers is a mass tort and class action research analyst with extensive knowledge of multi-district litigation (MDL), defective product cases, dangerous drug lawsuits, and toxic exposure claims across the United States. Victoria is not an attorney and the information provided is for educational purposes only.