Key takeaways
- Tirzepatide was on the FDA shortage list from December 2022 to December 19, 2024; while listed, 503A and 503B compounders could legally make copies of Zepbound and Mounjaro.
- After the grace periods ended (February 18, 2025 for 503A, March 19, 2025 for 503B), compounding a drug that is essentially a copy of an approved product became unlawful outside limited exceptions.
- A compounded version that differs in a way a prescriber documents as clinically necessary for a specific patient can still be lawful; 'personalized' doses and added vitamins are how providers try to fit that exception.
- Eli Lilly sued Mochi Health, Fella Health, Henry Meds and Willow in April 2025, alleging their marketing of compounded tirzepatide was unlawful; the cases were ongoing at our last review.
- For patients, the practical questions are whether the prescription documents a clinical reason, which pharmacy fills it, and whether the pharmacy is licensed in their state.
The short answer
Compounded tirzepatide is legal to dispense in 2026 when a licensed pharmacy compounds it for a specific patient on a prescription that documents a clinical reason the patient needs something other than the FDA-approved product. It is not legal to compound as a copy of Zepbound or Mounjaro, and it has not been since the grace periods after the shortage ended in early 2025. The whole 2026 telehealth market lives in the space between those two sentences.
How compounding law works
Section 503A of the Food, Drug, and Cosmetic Act permits a state-licensed pharmacy to compound a drug for an identified patient on a valid prescription, provided among other things that the compounded drug is not "essentially a copy of a commercially available drug product." Section 503B, added in 2013, permits FDA-registered outsourcing facilities to compound without patient-specific prescriptions, under current good manufacturing practice, with the same restriction on copies of approved products.
Both sections contain an exception: the restriction on copies does not apply to a drug that appears on the FDA's drug shortage list. That exception is why compounded semaglutide and tirzepatide exist at scale. Semaglutide entered the shortage list in March 2022 and tirzepatide in December 2022, and for the following two to three years compounders could lawfully produce copies.
The FDA's 2018 guidance documents define "essentially a copy." For 503A, a compounded drug is a copy if it has the same active ingredient, route, dosage form and strength as an approved product, unless the prescriber determines that a change produces a significant difference for the patient, and documents it. For 503B, the test is similar, with the added condition that the facility must obtain a statement from the prescriber about the clinical difference. Changing strength, removing an excipient a patient is allergic to, or combining with another ingredient can each qualify, if the change is clinically meaningful for that patient and not a device to evade the rule.
The timeline
December 2022. Tirzepatide added to the shortage list as demand for Mounjaro outran Lilly's supply.
October 2, 2024. The FDA removed tirzepatide from the shortage list, stating that Lilly's supply now met demand.
October 2024. The Outsourcing Facilities Association sued the FDA in the Northern District of Texas, arguing the determination was arbitrary. The FDA agreed to reconsider and said it would not enforce against compounders in the meantime.
December 19, 2024. After reconsideration, the FDA confirmed the shortage was resolved. It set enforcement-discretion periods: 503A pharmacies until February 18, 2025 and 503B facilities until March 19, 2025.
February 21, 2025. The FDA declared the semaglutide shortage resolved, with grace periods to April 22, 2025 (503A) and May 22, 2025 (503B).
March 2025. The Texas court declined to block the tirzepatide determination. Compounding copies of tirzepatide became unlawful for 503B facilities on March 19, 2025.
April 2025. Eli Lilly filed suits against Mochi Health, Fella Health, Henry Meds and Willow Health.
2025 to 2026. Telehealth prescribing of compounded tirzepatide continued, in modified forms, while litigation and FDA warning letters worked through the system.
April 30, 2026 (reported). According to a third-party comparison page dated June 2026 that we have not yet checked against the Federal Register, the FDA proposed removing tirzepatide from the 503B bulk drug substances list, with a comment period running to June 29, 2026. If accurate, the proposal concerns 503B bulk compounding, which had already wound down after March 2025, and does not change the 503A patient-specific pathway. No final rule had been issued as of that source's writing; we will update this timeline when we have confirmed the notice.
What "personalized" means
After March 2025, a compounded tirzepatide prescription had to differ from Zepbound in a clinically justified way. The market responded with three kinds of difference. Non-standard strengths and doses, for example 2 mg or 6 mg weekly rather than 2.5 or 5 mg, or vial concentrations that permit dose increments the pens do not offer. Added ingredients, most commonly vitamin B12 (cyanocobalamin or methylcobalamin), glycine, NAD+ or pyridoxine, presented as addressing nausea, fatigue or deficiency. Different dosage forms, such as sublingual drops and orally disintegrating tablets.
Each of these can be legitimate for an individual patient. A patient who vomits at 5 mg but tolerates 3.75 mg has a documented reason for a non-standard strength. A patient with B12 deficiency might reasonably receive B12. The legal problem arises when the same "personalized" formulation is prescribed to thousands of patients through a questionnaire, marketed on a homepage before any clinician has seen the patient, and offered at doses that track the approved schedule with a cosmetic change. The FDA has said that it does not regard changes made to evade the copy restriction as satisfying the standard, and has issued warning letters to compounders on that basis.
The Lilly lawsuits
In April 2025 Lilly filed complaints in federal court against four telehealth companies. The allegations, in summary: that the defendants marketed compounded tirzepatide as equivalent to or better than Zepbound without evidence; that their "personalized" dosing was a pretext for selling copies; that added ingredients such as vitamins were included without clinical basis and marketed with unsupported claims; that some products were tested and found to deviate from labelled potency or to contain impurities; and that the corporate entities, rather than independent clinicians, were effectively directing prescribing. The claims are brought under the Lanham Act (false advertising), state unfair-competition law and, in some complaints, allegations of the unlawful corporate practice of medicine.
The defendants have contested the claims and, in public statements, defended personalized compounding as lawful when clinically directed. As of our last review the cases were proceeding; no judgment had established a rule for the industry. We note the litigation on each defendant's provider page and do not adjust rankings for it, because the rankings are computed from price data and a lawsuit is not a price. A patient choosing one of these providers should know that the formulations they prescribe are the subject of active litigation and that an adverse outcome could change what they can dispense.
Lilly and Novo Nordisk have also sent cease-and-desist letters and filed suits against med-spas, pharmacies and smaller telehealth operators, and the FDA has issued warning letters to compounders over salt forms and marketing claims. The pressure runs in one direction.
What it means for a patient
The legality of a compounded prescription is, in practice, the responsibility of the prescriber and the pharmacy, not the patient. But a patient has a stake in it, because a prescription that does not meet the standard can be interrupted by a warning letter or a court order, and because the providers most aggressive in circumventing the rule are not necessarily the ones most careful about quality. Four questions are worth asking any provider before paying:
- What is the clinical reason my prescription differs from Zepbound, and is it documented in my chart?
- Which pharmacy will fill it, in which state, and is it licensed to ship to mine?
- Is the pharmacy 503A or 503B, and if 503B, is it on the FDA's registered list?
- If your ability to dispense this formulation changes, what happens to my prescription and my prepaid plan?
A provider that answers all four is operating in the open. A provider that cannot answer the first is a provider whose prescriptions may be copies; the compounding pharmacy guide covers the second and third.
What could change
Three things could reshape the market. A ruling in the Lilly cases that defines what personalization is permissible. FDA enforcement that moves from warning letters to seizures or injunctions against specific compounders. Or continued reductions in brand-name self-pay prices, which fell substantially in late 2025 and which, if they fall further, will make the legal question moot for many patients because the approved product will be close enough in price. The brand versus compounded article tracks that gap. We update this article when any of the three moves.
Frequently asked questions
Is compounded tirzepatide legal in 2026?
It is legal when a state-licensed 503A pharmacy or FDA-registered 503B facility compounds it on a valid prescription that documents a patient-specific clinical reason it differs from the approved product. Compounding a copy of Zepbound or Mounjaro has not been lawful since the shortage grace periods ended in February and March 2025.
Why can telehealth companies still sell compounded tirzepatide?
Because they prescribe versions that differ from the approved products, typically in strength, dosing schedule or added ingredients, and assert that the difference is clinically necessary for each patient. Whether that practice meets the legal standard is what Eli Lilly's 2025 lawsuits contest.
What did Eli Lilly sue over?
Lilly alleged that the defendants marketed compounded tirzepatide, including personalized doses and vitamin-added formulations, in ways that were false or misleading and that amounted to selling unapproved copies after the shortage ended. The companies have contested the claims.
Sources
- FDA. Clarification of FDA's Determination on the Tirzepatide Shortage. December 19, 2024.
- FDA. FDA clarifies policies for compounders as national GLP-1 supply begins to stabilize. February 21, 2025.
- 21 U.S.C. § 353a (section 503A) and § 353b (section 503B), Federal Food, Drug, and Cosmetic Act.
- FDA. Compounded Drug Products That Are Essentially Copies of a Commercially Available Drug Product Under Section 503A. Guidance for Industry, January 2018.
- FDA. Compounded Drug Products That Are Essentially Copies of Approved Drug Products Under Section 503B. Guidance for Industry, January 2018.
- Outsourcing Facilities Association v. FDA, N.D. Tex., filed October 2024 (tirzepatide shortage challenge).
- Eli Lilly and Company v. Mochi Health Corp. et al.; v. Fella Health; v. Henry Meds; v. Willow Health. Complaints filed April 2025.
- FDA. FDA's Concerns with Unapproved GLP-1 Drugs Used for Weight Loss. 2025.
Citations are to primary sources (peer-reviewed trials, FDA labeling and announcements, and provider pricing pages). See our sources policy and corrections log.