Compounded GLP-1s: what the FDA says

What compounding is for, and what it is not

The FDA describes compounding as a way to treat a patient whom no approved medicine can serve: someone allergic to a dye in the approved product, for example, or a child or older adult who cannot swallow a tablet and needs a liquid ^[3]. Compounders may also prepare versions of a drug on the FDA’s shortage list when the conditions in federal law are met ^[3]. That second route is the one that made compounded semaglutide and tirzepatide so common from 2022, and it is the one that has since closed for both.

Compounded drugs are not FDA approved, and they are not generics either. A generic drug is approved under its own section of the law and must, among other things, establish therapeutic equivalence to the brand-name product ^[3]. Among the telehealth red flags the FDA lists is a claim that a compounded drug is the same as an approved one ^[1].

Federal law recognises two kinds of compounder: pharmacies and physicians under section 503A, overseen mainly by state boards of pharmacy, and FDA-registered outsourcing facilities under section 503B, which follow current good manufacturing practice ^[3]. The article on 503A and 503B compounding explains the difference.

How the shortage years ended: a timeline

Both injectable medicines were in shortage from 2022 because demand rose faster than supply ^[2]. The FDA’s own update page records each step since then; the table below lists the main ones. When a shortage is resolved, the FDA generally considers the drug commercially available, which limits how much a 503A pharmacy may compound copies of it ^[2].

The status of other GLP-1 medicines differs. On 20 October 2026 the FDA Drug Shortages Database listed liraglutide injection as currently in shortage, while semaglutide and tirzepatide injections did not appear among current shortages ^[7]. Listings change, so the database itself is the place to check on any given day.

What “essentially a copy” means in 2026

Under section 503A, a pharmacy compounds for an individual patient on a prescription and may not regularly, or in inordinate amounts, make what are essentially copies of a commercially available drug ^[2]. The FDA’s guidance treats a compounded product as such a copy when it has the same active ingredient in the same, a similar or an easily substitutable strength, and the approved product can be used by the same route, unless the prescriber decides and documents that a change makes a significant difference for a named patient ^[2].

The April 2026 update applied this to combinations. A product mixing semaglutide with another ingredient such as vitamin B12 may count as a copy when both are injected and each amount is within 10% of the strength of a commercially available product ^[2]. For now, the FDA says it does not intend to act against a pharmacy that fills four or fewer prescriptions of such a product in a calendar month ^[2].

Outsourcing facilities face a different limit: they may compound from bulk ingredients only if the substance is on the 503B bulks list or the drug is on the shortage list at the time ^[2][5]. The FDA’s April 2026 proposal would keep semaglutide, tirzepatide and liraglutide off that list. In the press release and Federal Register notices checked for this article it remained a proposal awaiting a final determination ^[5][6].

Ingredients the FDA has singled out

• Salt forms: semaglutide sodium and semaglutide acetate are different active ingredients from the base form in approved products. The FDA has no information that they behave the same and knows of no lawful basis for compounding with them ^[1][4].
• Added ingredients: some compounders add vitamin B12, vitamin B6, L-carnitine or NAD to semaglutide; the FDA notes that the safety and effectiveness of these combinations have not been established ^[4].
• Retatrutide and cagrilintide: under federal law neither may be used in compounding; neither is part of an approved drug, and the FDA has warned companies that marketed, supplied or repackaged retatrutide ^[1].
• Research-use products: the FDA has warned companies selling semaglutide, tirzepatide, retatrutide, survodutide or mazdutide labelled for research or not for human use, yet sold to consumers with dosing instructions ^[1].
• Imported ingredients: an FDA import alert (66-80) aims to keep GLP-1 active ingredients with possible quality problems out of the US, while allowing those from manufacturers that appear compliant ^[1].

Dosing errors: why vials and units cause confusion

Approved injectable semaglutide is dosed in milligrams, comes in standard strengths and, when the FDA wrote its 2024 alert, was sold only in prefilled pens. Compounded products may come in multiple-dose vials or syringes, in several concentrations, sometimes with instructions written in “units” whose volume depends on the concentration ^[4].

In the reports the FDA reviewed, many patients had no experience drawing medicine from a vial. Most errors involved drawing up more than prescribed, with people injecting five to 20 times the intended dose; in other cases clinicians converted milligrams into units or millilitres incorrectly, giving five to ten times the intended amount ^[4]. Reported effects included nausea, vomiting, abdominal pain, fainting, headache, dehydration, acute pancreatitis and gallstones ^[4].

The FDA has also received reports linked to doses beyond the approved labels: larger single doses, more frequent doses or faster increases ^[1]. It asks prescribers to be vigilant and encourages patients to ask their prescriber or the compounder how to measure the intended dose ^[1][4].

A study of the FDA’s adverse event database from 2018 to 2024 found 707 reports involving compounded products among 81,078 GLP-1 reports. Compounded products had higher reporting odds for preparation errors, contamination and hospitalisation ^[8]. Spontaneous reports cannot show cause and effect, and the authors say so ^[8].

Vials, storage and deliveries

The FDA generally recommends using a multiple-dose vial of a sterile medicine within 28 days of first use, because the risk of contamination rises after that. If medicine remains at day 28, it advises discarding the vial even when the compounder’s instructions allow longer, and using a new sterile needle and syringe for every dose ^[1].

Injectable GLP-1 medicines need refrigeration. After complaints of compounded products arriving warm or with too little ice, the FDA recommends not using one that arrives warm or poorly chilled ^[1].

Red flags the FDA lists for online sellers

• Claims that a compounded drug is the same as an FDA-approved one ^[1].
• Very deep discounts, or prices that look too good to be true ^[1].
• Medicine that differs from what you received before or from the website photo, or that arrives damaged or without instructions for use ^[1].
• No screening and prescription by a licensed doctor before the medicine is sent, and no licensed doctor to answer questions afterwards ^[1].
• Spelling errors or a wrong pharmacy address on the label, or a pharmacy name you suspect is fraudulent. The FDA knows of labels naming pharmacies that do not exist, or licensed pharmacies that did not make the product ^[1].

If you already use a compounded product

The FDA’s practical steps are short: get prescriptions from your doctor, fill them at a state-licensed pharmacy, and contact the compounder or telehealth platform with any question about the label or instructions ^[1]. Its BeSafeRx pages explain how to look an online pharmacy up in your state board of pharmacy’s licence database ^[9].

Useful facts to have ready for your prescriber or pharmacist are the product’s concentration, the dose in milligrams as well as in units, the date the vial was first used and where it came from. Whether to continue, change or stop a product is a decision for your prescriber. Problems, including suspected quality issues, can be reported to the FDA’s MedWatch programme online or by fax ^[1].

Ozempic® and Wegovy® are registered trademarks of Novo Nordisk A/S. Mounjaro® and Zepbound® are registered trademarks of Eli Lilly and Company. PepLabo is not affiliated with or endorsed by Novo Nordisk or Eli Lilly and Company, and does not sell, recommend or link to any compounded or approved medicine, pharmacy or telehealth company.