Court finds no proximate cause in Lilly's suit against a compounded tirzepatide telehealth platform

Courts are reaching different conclusions on whether Eli Lilly can sue telehealth companies that sell compounded tirzepatide, the active ingredient in Lilly's Mounjaro and Zepbound. On August 29, 2025, a federal court in the Central District of California ruled in Eli Lilly & Co. v. Willow Health Services that the requirement for a physician's prescription broke the legal chain between the company's marketing and any harm to Lilly, defeating the drugmaker's false-advertising claims. About eight months later, a different federal court reached the opposite result in a similar case against another telehealth company, Mochi Health Corp. The full text of the Willow Health Services ruling was not available for this story, so its exact reasoning is not yet confirmed here beyond what is summarized above.

In the Mochi Health case, filed in the Northern District of California, Lilly accused the company of running a scheme to steer customers toward compounded versions of Mounjaro and Zepbound instead of Lilly's FDA-approved products ^[1]. Lilly's amended complaint says Mochi Health changed the doses of its compounded tirzepatide several times without a documented clinical reason: it allegedly moved away from doses of 2.5 mg, 5 mg, 7.5 mg, 10 mg, 12.5 mg, and 15 mg before December 2024, changed them again in March 2025, and altered both the doses and the formulation in September 2025 after starting a new relationship with Lexington Compounding Pharmacy ^[1]. Lilly also alleges the compounded products contained added ingredients such as niacinamide, glycine, and pyridoxine that varied by pharmacy and were not meant to have a therapeutic purpose, but instead reflected the company's business arrangements ^[1].

Lilly's Lanham Act claim says Mochi Health falsely told consumers its compounded drug was safe and effective based on studies of Lilly's own FDA-approved products, falsely implied FDA approval, and called the product "personalized" ^[1]. Lilly points to research showing higher rates of side effects such as abdominal pain, diarrhea, nausea, suicidality, and cholecystitis tied to compounded versions, arguing that blending its brand name with an inferior product harms its reputation ^[1].

On the question of standing, the court found Lilly had adequately alleged economic injury because Mochi Health allegedly controls the physicians who write the prescriptions — hiring them, training them, and setting treatment protocols — and can unilaterally change dosing, which the court said supports a plausible claim that Mochi Health diverts sales away from Lilly's approved drugs ^[1]. That reasoning lets Lilly's case proceed past the motion-to-dismiss stage, in contrast to the outcome in the earlier Willow Health Services matter.

Why it matters for patients

The split between these two rulings means the legal rules for telehealth platforms that sell compounded tirzepatide are still unsettled. For patients, that uncertainty could affect what compounded products remain on the market, how they are advertised, and what those platforms are allowed to say about safety or FDA status going forward. The Mochi Health order does not decide whether Lilly will ultimately win; it only allows the case to continue past an early motion to dismiss ^[1]. Nothing in the available record addresses the clinical safety of any specific compounded product beyond the general adverse-event studies Lilly cited ^[1].

What happens next

The Mochi Health case now moves forward on Lilly's Unfair Competition Law, Lanham Act, and conspiracy claims, based on the court's order on the motion to dismiss the First Amended Complaint ^[1]. No trial date or further schedule is included in the available text. It is not yet known from the sources reviewed how the Willow Health Services case will proceed or whether either ruling will be appealed.