The FDA has sent a warning letter to Empower Pharmacy — the Houston-based operation widely described as the largest compounding pharmacy in the country — over its compounded semaglutide and tirzepatide products. The letter is dated September 18, 2026, was posted to the FDA's database on September 22, and by the end of the week had drawn coverage from CBS News, Endpoints and a wave of pharmacy-law analyses.
Every previous round of GLP-1 enforcement this year targeted marketers — telehealth sites and research-peptide storefronts. This one targets the manufacturing layer itself, and it goes after the specific formulation trick that has kept compounded GLP-1s on the market since the shortages ended: adding vitamin B12 or niacinamide and calling the result a different drug.
Research-context information only. This article reports on federal agency correspondence and news coverage of it as published. A warning letter states the FDA's allegations and is not a court finding. Semaglutide and tirzepatide are the active ingredients in FDA-approved products for type 2 diabetes and chronic weight management; compounded and research-peptide forms are not FDA-approved. Nothing here is medical or legal advice. Consult a licensed physician for personal medical decisions.
What the letter actually says
The letter — Warning Letter 738238, addressed to Empower Clinic Services, LLC dba Empower Pharmacy and its founder and CEO — names three product lines:
| Product cited | Strength | Format |
|---|---|---|
| Tirzepatide / niacinamide | 17 mg/mL + 2 mg/mL | 4 mL vial |
| Tirzepatide / niacinamide | 8 mg/mL + 2 mg/mL | 2.5 mL vial |
| Semaglutide / cyanocobalamin (B12) | 5 mg/mL + 0.5 mg/mL | 1 mL vial |
The FDA's charges run on two separate tracks.
Track one: the products are "essentially copies" of approved drugs. Section 503A of the Food, Drug and Cosmetic Act lets a licensed pharmacy compound a drug that already has an approved version only in limited circumstances — most relevantly, when a prescriber determines the compounded formulation produces a significant difference for a specific patient. The FDA reviewed Empower's records and found those prescriber determinations "repeated verbatim across many records," and said that generating prescriptions in ways that undermine individualized clinical judgment "call[s] the individualized nature of those determinations into question." Volumes were redacted, but the agency described output across four consecutive months of 2025 as "inordinate amounts."
Track two: sterile-manufacturing deficiencies. The letter cites inadequate smoke studies demonstrating unidirectional airflow in ISO 5 areas, media fills not run under worst-case conditions, gaps in environmental monitoring of aseptic processing areas, and a quality unit that failed to catch documentation discrepancies — including vial counts that didn't match records. BioSpace's coverage led with the statutory language the agency invoked: drugs prepared under insanitary conditions whereby they may have been "contaminated with filth."
The formal violations are adulteration under section 501(a)(2)(A), unapproved new drugs under section 505, and misbranding under section 502(f)(1). Empower was given 15 working days to respond, with the standard closing warning that failure to address the violations can lead to "seizure and injunction" without further notice.
Empower's public response, given to CBS News, was that it has "already remediated many of the issues outlined in the Warning Letter" and will "continue to work cooperatively with the agency to ensure patient access to quality compounded drug products."
The B12 loophole, explained
When the FDA declared the tirzepatide shortage resolved in December 2024 and the semaglutide shortage in February 2025, the legal basis for mass-compounding straight copies disappeared. The agency formally ended its enforcement discretion for compounded tirzepatide in March 2025 and for semaglutide in April 2025 — dates the Empower letter itself recites.
The industry's answer was reformulation. Add cyanocobalamin to semaglutide, or niacinamide to tirzepatide, obtain a prescriber's statement that the add-in makes a significant difference for the patient, and the product arguably stops being a copy. That formulation pattern — the exact one named in this letter — became the backbone of the post-shortage compounded GLP-1 market and the telehealth platforms built on it.
This letter is the FDA's most direct statement yet that it does not accept the workaround. The agency's reasoning, as Buchanan Ingersoll's pharmacy-law analysis puts it, is that a co-formulation with B12 or niacinamide remains an essential copy unless the significant-difference determination is genuinely individualized — and copy-pasted prescriber attestations across hundreds of records are evidence that it isn't. The Frier Levitt analysis reads the letter the same way: the scrutiny now falls on prescription documentation, production volume, and the role of third-party prescribing platforms, not just on what's in the vial.
Because the reasoning attacks the documentation pattern rather than anything unique to Empower, it applies to every 503A pharmacy running the same playbook. That is why the legal community treated a single warning letter as sector news.
What this means for compounded GLP-1 supply
The practical read from people who advise these businesses is evolution, not shutdown. Healthcare lawyer Darshan Kulkarni told CBS News he expects compounders to change marketing and documentation practices rather than halt production — while cautioning that "that avenue is definitely getting narrower."
Three distinct markets now exist for these two molecules:
- Compounded via telehealth or a 503A pharmacy. Still operating, but this letter squarely targets its legal basis. The realistic near-term effects are reformulations, stricter per-patient documentation, higher friction, and possible supply interruptions at pharmacies that draw FDA attention. Two pending decisions could tighten it further — the drug-vs-biologic reclassification case and the proposal to exclude GLP-1s from 503B compounding even if shortages return. State-level rules already vary widely; our state-by-state compounding law summary tracks that layer.
- FDA-approved products. The approved semaglutide and tirzepatide injections and the oral options remain the fully-inside-the-system route. Orforglipron, approved in April, runs $149-299/month at cash pricing and removed the injection barrier entirely.
- The research-use-only market. Peptide vendors sell semaglutide and tirzepatide labeled for research purposes only, not FDA-approved for human use — a different legal category from compounded drugs, covered by a different enforcement track. Vendors with published third-party COAs continue to list both compounds; our semaglutide buying guide and tirzepatide buying guide track current per-mg pricing across that market.
