# What Is in a Compounded GLP-1 Vial: How to Read the Label By Ruth Calder, Enforcement Editor (https://glpwatchdog.org/authors/ruth-calder) | Published: 2026-08-14 | Updated: 2026-11-02 Canonical page: https://glpwatchdog.org/research/what-is-in-a-compounded-glp1-vial > An approved pen delivers a dose; a compounded vial delivers a concentration, and someone has to convert one into the other. This is how to read the label, not how to dose. ## Key points - An approved pen fixes both the concentration and the dose; a compounded vial fixes only the concentration, moving the arithmetic to the patient. - FDA has reports of patients administering five to twenty times the intended amount of compounded semaglutide, some seeking medical attention or hospitalized. - On a U-100 insulin syringe, one unit measures volume: one hundredth of a milliliter. A units instruction therefore does not carry across vials of different concentration. - A beyond-use date is counted from the date of compounding and is not an expiration date; 21 U.S.C. 353b(a)(10) lists what a 503B label must state, and there is no federal equivalent for a 503A vial. An approved GLP-1 pen delivers a dose. A compounded vial delivers a concentration, and someone has to turn that concentration into a dose. When the vial arrives by mail, that someone is usually you. FDA has collected reports of what happens next: patients who administered five to twenty times what was intended, some of whom sought medical attention or were hospitalized. > **This page teaches you to read a label. It prescribes nothing.** There is no dose here, no ladder and no volume to draw, deliberately. If your label does not match what you were told, or two documents disagree, do not resolve it with arithmetic of your own. Call the prescriber who wrote the prescription and the pharmacy that filled it, before the next injection. ## Concentration is not dose A dose is an amount of drug, written in milligrams. A concentration is how tightly that drug is packed into liquid, written in milligrams per milliliter. A vial labeled 2 mg/mL holds two milligrams of drug in every milliliter of solution. A vial labeled 5 mg/mL holds two and a half times as much in the same milliliter. Both vials can fill the same prescription. They cannot do it with the same volume. The approved products removed this problem by fixing both numbers. In its 2024 alert FDA described Wegovy as single-dose pre-filled pens that deliver a preset dose once weekly, Ozempic as multiple-dose pre-filled pens designed for once-weekly dosing, and Rybelsus as an oral tablet.[1] Wegovy’s current label also lists tablets and a multi-dose pen, and that pen still meters the dose: it delivers four fixed 2.4 mg doses.[6] The pen holds the concentration constant and does the measuring, and the strength is printed on a label FDA reviewed.[6][7] A compounded vial carries no such review. Compounded drugs are not FDA-approved, so nobody at FDA has checked the safety, effectiveness or quality of the one in your refrigerator.[3] Nothing about the vial format is dishonest, but it moves a calculation out of the factory and onto a kitchen table. FDA has said plainly what varies. Compounders offer semaglutide in different containers, including multiple-dose vials and prefilled syringes; concentrations may differ depending on the compounder; and a single compounder may offer several concentrations of its own.[1] So there is no standard vial to compare yours with. ## Why units are the part that catches people The syringe most people are sent with a compounded GLP-1 is an insulin syringe. Its barrel is marked in units, not milliliters. A U-100 syringe holds one milliliter across one hundred units, so a unit on that barrel is one hundredth of a milliliter. FDA's own alert spells the conversion out in passing when it describes patients instructed to draw a five-unit dose, which it writes as 0.05 milliliters.[1] > **A unit is a volume, not an amount of drug.** The syringe measures how much liquid you have drawn. How many milligrams are sitting in that liquid depends entirely on the concentration of the vial it came from. Draw the same number of units from two vials of different concentration and you get two different amounts of drug. That is why a units instruction does not travel. If a pharmacy changes its concentration, or your prescription moves to a different pharmacy, a number of units you remember from before describes a different amount of drug, and nothing on the syringe will tell you. FDA's reports include providers who made the conversion wrong in the same direction: one meant to prescribe five units and wrote twenty-five, and another prescribed twenty units instead of two, affecting three patients who received ten times what was intended and became nauseated and vomited.[1] The largest group of reports was simpler and harder to guard against. Most described patients drawing up more than the prescribed dose from a multiple-dose vial during self-administration, many of them unfamiliar with measuring from a syringe at all. In several, patients directed to give five units on a U-100 syringe gave fifty.[1] In one, a patient could not get clear dosing instructions from the telemedicine provider who wrote the prescription, searched online for medical advice, and took five times the intended amount.[1] Reported consequences included nausea, vomiting, abdominal pain, fainting, headache, [migraine](https://glpwatchdog.org/research/glp1-and-migraine), dehydration, acute pancreatitis and gallstones, with some patients hospitalized. Semaglutide's half-life is about a week, so FDA notes that observation and treatment after an overdose may need to be prolonged.[1] ## Two vials, one prescription, different volumes Put the two facts together and the practical trap appears. Suppose your prescription is unchanged and your pharmacy changes, or your pharmacy reformulates. If the new vial is twice the concentration of the old one, the same prescribed milligram amount now lives in half the volume, and therefore in half the number of syringe units. Drawing to the mark you are used to would deliver twice the drug. Do not recalculate anything yourself; treat a new vial as a reason to ask again. When the box changes, the number on the syringe is the last thing to assume is unchanged, and the pharmacy that prepared it should tell you how it is meant to be measured. FDA's advice to patients is exactly that: talk to your health care provider or compounder about how to measure and administer the intended dose.[1] When a seller names several pharmacies, ask which one is filling your order each time. [Madison Meds](https://glpwatchdog.org/reviews/madison-meds) lists five partner compounding pharmacies, from [Epiq Scripts](https://glpwatchdog.org/pharmacies/epiq-scripts) to Striker Pharmacy. [Vita Stack Health](https://glpwatchdog.org/reviews/vita-stack-health) names three: EPIQ Scripts, Foothills Pharmacy and Emerald Compounding Pharmacy. The terms at [DTC Clinic](https://glpwatchdog.org/reviews/dtc-clinic) name RedRock Pharmacy, Precision Compounding Pharmacy and [Triad Rx](https://glpwatchdog.org/pharmacies/triad-rx). [Embody](https://glpwatchdog.org/reviews/embody) names four partner pharmacies for its compounded semaglutide and tirzepatide, among them Red Rock Compounding Pharmacy and Triad Rx. Some prescriptions come with no scheduled conversation in which to ask. [Bliv](https://glpwatchdog.org/reviews/bliv), for example, prescribes compounded semaglutide through an online intake with no phone or video visit, so if a refill arrives in a different vial, the question about measuring it is one you will have to raise yourself. Your bill will not warn you either. [Yucca Health](https://glpwatchdog.org/reviews/yucca-health), [Gimme Care](https://glpwatchdog.org/reviews/gimme-care) and [RxSaludable](https://glpwatchdog.org/reviews/rxsaludable) charge the same price at every dose, as do [Precision Telemed](https://glpwatchdog.org/reviews/precision-telemed) and [Blue Haven RX](https://glpwatchdog.org/reviews/blue-haven-rx), so a step up the ladder or a new vial can arrive with an identical invoice. Under flat pricing, the label is the only paperwork that changes. Precision Telemed also lists a certificate of analysis among its features, so ask to see it beside the label. [Trinity Meds](https://glpwatchdog.org/reviews/trinity-meds) ships its injections with a kit of syringes, needles and alcohol swabs, and names the four pharmacies that may have prepared it. ## What the label should state Federal law sets an explicit list for drugs from a 503B outsourcing facility. Under 21 U.S.C. 353b(a)(10), the label must carry the statement “This is a compounded drug” or a comparable statement identifying it as one, the name and address and phone number of the outsourcing facility, and for the drug itself the lot or batch number, the established name, the dosage form and strength, the statement of quantity or volume, the date it was compounded, the expiration date, storage and handling instructions, the National Drug Code if there is one, the statement “Not for resale”, and a list of active and inactive ingredients with the quantity or proportion of each.[2] That list describes a complete label well, but it binds outsourcing facilities only. A 503A pharmacy compounding for one identified patient works to state board requirements and USP standards instead, and there is no equivalent federal enumeration for the vial it sends you. Which route your seller uses is covered in [which GLP-1s can be compounded](https://glpwatchdog.org/research/which-glp1-can-be-compounded), and the pharmacy behind each seller we can trace is in our [pharmacy register](https://glpwatchdog.org/pharmacies). - **The strength, as a concentration.** Milligrams per milliliter, and the total volume in the vial. This is the number that changes what a syringe unit means. - **Every ingredient, active and inactive.** If a vitamin or a preservative is in there, it belongs on the label with its own quantity. - **A lot or batch number.** Without it a recall cannot reach you and a complaint cannot be traced. - **The date compounded and the beyond-use date.** Two dates, not one. - **Storage and handling instructions**, including whether it is refrigerated and what to do if it was not. - **The pharmacy's name, address and telephone number.** If the vial names no pharmacy, you cannot verify anything about who made it. See [how to verify an online GLP-1 pharmacy](https://glpwatchdog.org/research/how-to-verify-an-online-glp1-pharmacy). ## Beyond-use dating is not an expiration date A manufactured drug carries an expiration date supported by stability testing of that product in that container. A compounded preparation carries a beyond-use date, which USP defines as the date or time after which the preparation may not be stored or transported, calculated from the date or time of compounding.[4] It is a limit on the preparation, set by the pharmacy, and it is generally much shorter than an expiration date because it has to account for chemical degradation, microbial growth and the integrity of the container all at once.[4] The standards that govern how those dates are assigned, USP General Chapters <795>, <797>, <800> and <825>, became official on November 1, 2023.[5] For sterile preparations the permitted dating depends heavily on the conditions the pharmacy compounded under and on what testing it performed, which is why two pharmacies can lawfully assign very different dates to superficially similar vials. Read your two dates as two different pieces of information, and read the storage line with them. A beyond-use date assumes the storage conditions on the label were kept. If a shipment sat warm, or arrived without a cold pack that the label implies it should have had, that is a call to the pharmacy rather than a judgment call for you. ## What B12 and other additions change Many compounded vials contain more than the GLP-1. FDA has stated it is aware of compounders adding cyanocobalamin (vitamin B12), pyridoxine (vitamin B6), [levocarnitine](https://glpwatchdog.org/research/l-carnitine-injections-evidence) and nicotinamide adenine dinucleotide to semaglutide products, and that the safety and effectiveness of combining semaglutide with other ingredients has not been established.[1] No approved semaglutide injection contains a vitamin at all. We go through the three explanations offered for the B12 pairing, and which of them has a document behind it, in [why compounded semaglutide is mixed with B12](https://glpwatchdog.org/research/semaglutide-compounded-with-b12). Seller listings often show the combination before the label does. [VitaStir](https://glpwatchdog.org/reviews/vitastir) sells semaglutide with B12 and tirzepatide with glycine and B12 as home kits, [Alegro Health](https://glpwatchdog.org/reviews/alegro-health) sells a semaglutide starter course with B12, and [HumeCare+](https://glpwatchdog.org/reviews/humecare) lists tirzepatide with vitamin B12 and glycine. For label reading, a combination vial does one specific thing: it puts a second number on the label. The concentration of the GLP-1 and the concentration of the added ingredient are separate figures, and a milligram figure printed alone can belong to either. If your label carries a strength that does not identify which ingredient it describes, that ambiguity is the pharmacy's to resolve, not yours. > **Check which molecule the label names.** FDA has said it received reports that some compounders may be using salt forms (semaglutide sodium and semaglutide acetate) and has been explicit that the salt forms are different active ingredients from the base form used in the approved drugs.[1] The agency has separately warned about unapproved and counterfeit GLP-1 products reaching patients, and its instruction for buying at all is to use a state-licensed pharmacy.[8] A label naming a salt form is not naming the same substance as the approved product, so raise it with the prescriber before the vial is opened. ## When the label and the instructions disagree Do not reconcile it yourself. Photograph the vial label, the carton and any instruction sheet, then contact both the pharmacy named on the label and the clinician who wrote the prescription, and do not inject until they agree. In the errors FDA documented, the wrong number came from a patient measuring a dose on their own or a provider converting milligrams to units.[1] 1. **Stop before the injection.** A missed timing question is a question for the prescriber; a wrong amount cannot be taken back. 2. **Photograph everything**, including the lot number and both dates. 3. **Call the pharmacy named on the label** and ask what concentration this vial is and how the prescribed amount is meant to be measured from it. 4. **Call the prescriber** and confirm the prescription against what the pharmacy said. 5. **Report it to FDA** through MedWatch if a dosing error or an adverse event occurred. FDA asks patients, providers and compounders alike to report these.[1] > We track which pharmacy stands behind each seller we can trace, and what FDA has published about them, in our [pharmacy register](https://glpwatchdog.org/pharmacies) and our [warning letter register](https://glpwatchdog.org/fda-warning-letters). What no public register carries is the concentration in the vial you were sent. That number exists only on your label and in the pharmacy's records, which is why the label is the document that matters. ## Frequently asked questions ### My vial is labeled in mg/mL and my instructions are in units. Which do I follow? Neither, until they have been reconciled by the people responsible for them. Units measure volume on the syringe and milligrams per milliliter describe the vial, so translating between them requires knowing the exact concentration of the vial in your hand. Call the pharmacy named on the label and the prescriber, and do not inject until both agree. ### Why does my new vial look like a different amount of liquid than the old one? Compounded products are not standardized between pharmacies, and a single compounder may offer more than one concentration. A different concentration means the same prescribed amount occupies a different volume. Treat a change of vial, pharmacy or formulation as a reason to have the measurement explained again rather than carried over. ### What is a beyond-use date and why is it so much sooner than an expiration date? USP defines it as the point, counted from the time of compounding, past which the preparation may not be stored or transported. It runs shorter than the expiration date on a manufactured drug because it has to cover chemical stability, microbial growth and the container closure together, without the product-specific stability testing behind an approved drug's date. ### Does B12 in the vial make the medication work better? That has not been established. FDA has said the safety and effectiveness of combining semaglutide with other ingredients has not been established, and no approved semaglutide injection contains a vitamin. What the addition definitely does is put a second ingredient and a second number on the label, which is a reason to read it carefully. ### The vial does not name a pharmacy. What now? Then there is no one to ask the concentration question of, and no license to look up. Federal law requires an outsourcing facility to put its name, address and telephone number on the label. A vial that names nobody should go to the prescriber before it goes anywhere near a syringe. ## References 1. U.S. Food and Drug Administration FDA alerts health care providers, compounders and patients of dosing errors associated with compounded injectable semaglutide products. FDA Human Drug Compounding. 2024. https://www.fda.gov/drugs/human-drug-compounding/fda-alerts-health-care-providers-compounders-and-patients-dosing-errors-associated-compounded 2. Office of the Law Revision Counsel, U.S. House of Representatives 21 U.S.C. 353b(a)(10): Outsourcing facilities — Labeling of drugs. United States Code. 2025. https://www.law.cornell.edu/uscode/text/21/353b 3. U.S. Food and Drug Administration Compounding and the FDA: Questions and Answers. FDA Human Drug Compounding. 2025. https://www.fda.gov/drugs/human-drug-compounding/compounding-and-fda-questions-and-answers 4. United States Pharmacopeia USP Compounding Standards and Beyond-Use Dates (BUDs). USP Compounding Standards. 2019. https://www.usp.org/sites/default/files/usp/document/our-work/compounding/usp-bud-factsheet.pdf 5. United States Pharmacopeia Compounding Standards Updates. USP Compounding. 2023. https://www.usp.org/compounding/updates 6. Novo Nordisk Pharmaceutical Industries, Lp WEGOVY (SEMAGLUTIDE) INJECTION, SOLUTION WEGOVY (SEMAGLUTIDE) TABLET. DailyMed Structured Product Label. 2026. https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=ee06186f-2aa3-4990-a760-757579d8f77b 7. Eli Lilly and Company MOUNJARO (TIRZEPATIDE) INJECTION, SOLUTION MOUNJARO KWIKPEN (TIRZEPATIDE) INJECTION, SOLUTION. DailyMed Structured Product Label. 2026. https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=d2d7da5d-ad07-4228-955f-cf7e355c8cc0 8. U.S. Food and Drug Administration FDA's Concerns with Unapproved GLP-1 Drugs Used for Weight Loss. FDA Drug Alerts and Statements. 2026. https://www.fda.gov/drugs/drug-alerts-and-statements/fdas-concerns-unapproved-glp-1-drugs-used-weight-loss --- Cite as: GLP Watchdog, Ruth Calder, "What Is in a Compounded GLP-1 Vial: How to Read the Label", published 2026-08-14, updated 2026-11-02. https://glpwatchdog.org/research/what-is-in-a-compounded-glp1-vial Canonical HTML page: https://glpwatchdog.org/research/what-is-in-a-compounded-glp1-vial Medical disclaimer: Nothing here is medical advice. We report on this subject; we do not treat anyone. Whether to begin a medication, supplement, or treatment, whether to adjust it, and whether to stop are questions for a clinician licensed to answer them, who knows your history.