# Mounjaro & Zepbound Pens vs Compounded Vials **By TelosRX Editorial Team** ยท 2026-08-17 **A Mounjaro pen is Eli Lilly's prefilled tirzepatide injector, sold as a single-dose pen or as a four-dose KwikPen. Compounded tirzepatide from [Telos Rx](https://www.telosrx.com/pages/tirzepatide) instead ships as a vial with syringes, which changes handling, storage and dose flexibility.** Most articles cover the molecule and skip the container, which is the part you hold every week. This page is about formats: the single-dose pen, what the KwikPen changed, and how a vial with syringes differs. Technique lives in [how to inject tirzepatide](https://www.telosrx.com/blogs/glp1/how-to-inject-tirzepatide). ## Same Molecule, Several Containers Mounjaro and Zepbound are both tirzepatide, a dual GIP and GLP-1 receptor agonist from Eli Lilly. Mounjaro was approved in 2022 for type 2 diabetes. Zepbound was approved in November 2023 for chronic weight management, and in December 2024 for moderate to severe obstructive sleep apnea in adults with obesity. **The brand difference is the indication, not the drug.** Device format is a separate axis. The naming overlap is unpacked in [is Mounjaro tirzepatide](https://www.telosrx.com/blogs/glp1/is-mounjaro-tirzepatide-explained) and [is Zepbound the same as tirzepatide](https://www.telosrx.com/blogs/glp1/is-zepbound-the-same-as-tirzepatide). The current [Mounjaro prescribing information on DailyMed](https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=d2d7da5d-ad07-4228-955f-cf7e355c8cc0) lists prefilled single-dose pens, single-dose vials, multi-dose vials and single-patient-use KwikPens. So a vial is not automatically a compounded product. Lilly ships vials too. ## The Single-Dose Pen: One Device, One Injection The original Mounjaro pen and the Zepbound pen are single-dose autoinjectors. Each holds 0.5 mL and delivers one fixed strength: 2.5, 5, 7.5, 10, 12.5 or 15 mg. You use it once and discard it. The dose is set at the factory, so there is no dial and nothing to measure. A month means four separate pens, and stepping up titration means a new prescription at a new strength rather than a new setting. That fixed-strength design shapes the brand titration schedule: 2.5 mg weekly for four weeks, then 2.5 mg increments no sooner than four weeks apart, to a maximum of 15 mg weekly. The full ladder is in [tirzepatide dosage](https://www.telosrx.com/blogs/glp1/tirzepatide-dosage-schedule). Those figures describe the label, not instructions for you. ## The KwikPen: Four Weekly Doses in One Device The KwikPen is the newer multi-dose format, and the reason searches for the Mounjaro KwikPen climbed so fast. The [Zepbound prescribing information](https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=487cd7e7-434c-4925-99fa-aa80b1cc776b) describes the single-patient-use KwikPen as holding 2.4 mL, which provides four doses of 0.6 mL each. Per-injection strengths mirror the single-dose range, so a KwikPen holding four 2.5 mg doses is labelled 10 mg per 2.4 mL and one holding four 15 mg doses is labelled 60 mg per 2.4 mL. The Zepbound KwikPen and Mounjaro KwikPen share that architecture. **A KwikPen is still a fixed-strength device.** It cuts four objects in your fridge down to one, but it does not let you pick a dose between the labelled steps. Each pen is for one person and is never shared, even with a fresh needle. ## Compounded Tirzepatide: A Vial and Syringes Compounded tirzepatide is prepared by a licensed US compounding pharmacy against a prescription written for an individual patient. **It is not FDA-approved.** That is the most important sentence on this page, and it holds no matter how the medication is packaged. What arrives is a sealed vial of solution plus separate syringes. You draw the prescribed volume yourself rather than pressing a preloaded plunger, which is why compounded prescriptions are usually written in millilitres or units alongside the milligram figure. The arithmetic is in [tirzepatide dosing in mL](https://www.telosrx.com/blogs/glp1/tirzepatide-dosing-in-ml). That drawn-dose step is the practical difference. It adds a measurement task a pen removes, and in exchange allows a prescribed volume that need not land on a brand step. That is what makes [microdosed tirzepatide](https://www.telosrx.com/pages/microdosed-tirzepatide) and the [microdosing tirzepatide schedule](https://www.telosrx.com/blogs/glp1/microdosing-tirzepatide-schedule) possible. ## Device Comparison: Pen, KwikPen and Vial Single-dose pen (Mounjaro / Zepbound) KwikPen (Mounjaro / Zepbound) Compounded tirzepatide vial **Format** Prefilled autoinjector, single use Prefilled multi-dose pen, one patient Sealed vial plus syringes **Doses per device** 1 4 weekly doses Varies by prescription and vial **Volume per dose** 0.5 mL, preset 0.6 mL, preset (2.4 mL total) Drawn to the prescribed volume **Labelled strengths** 2.5, 5, 7.5, 10, 12.5 or 15 mg Same strengths, four doses each Set by the pharmacy preparation **Dose flexibility** None; strength changes by prescription None; four identical doses Volumes between brand steps possible **Measuring required** No No Yes, drawn into the syringe **Label storage, unopened** Refrigerate 2 to 8 C; up to 21 days total below 30 C Refrigerate 2 to 8 C; discard after 30 days at room temperature Per the pharmacy label supplied **Label storage, after first use** Not applicable Discard 30 days from first use, or after 4 doses Beyond-use date set by the pharmacy **What ships to you** One pen per dose, needle built in One pen per four weeks, plus needles Vial, syringes, wipes, sharps guidance **Regulatory status** FDA-approved FDA-approved Not FDA-approved; compounded under federal regulations No row there says one device works better in the body. The molecule goes in subcutaneously either way. What differs is packaging, measurement, storage rules and dose granularity. If a vial and syringe format suits how you would rather manage a weekly dose, the next step is a written intake reviewed by a licensed provider. Compounded tirzepatide at Telos Rx is as low as $139 per month as of publication, with flat pricing that does not rise with your dose. [See compounded tirzepatide](https://www.telosrx.com/pages/tirzepatide) ## Storage Is Where the Formats Diverge Most The labels treat single-use and multi-use containers differently, and the numbers matter before a heatwave or a flight. A single-dose pen or vial is refrigerated at 2 to 8 degrees Celsius, and may sit below 30 degrees Celsius for up to 21 days total before it is discarded. An unopened KwikPen or multi-dose vial is also refrigerated, and is discarded after 30 days at room temperature. Once used, the label directs discarding it after a total of 30 days at room temperature, 30 days from first use, or after four weekly doses, whichever comes first, even if solution remains. **Compounded vials carry their own beyond-use date on the pharmacy label.** That date is set by the preparing pharmacy for that preparation, so the printed label, not a brand insert, governs your vial. ## Semaglutide Devices Follow a Different Pattern Multi-dose pens are not new to this drug class. The [Ozempic injection label](https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=adec4fd2-6858-4c99-91d4-531f5f2a2d79) describes 3 mL single-patient-use pens delivering several weekly doses, for example a 4 mg per 3 mL pen supplying four 1 mg doses. Semaglutide arrived with a multi-dose pen; tirzepatide started single-dose and added the KwikPen later. Semaglutide has since moved past the pen as well: it is now supplied as oral tablets under both the Ozempic and Wegovy names alongside the injections, so a brand name alone no longer tells you the format. Compounded semaglutide, like compounded tirzepatide, is not FDA-approved and is typically supplied as a vial. And on formats: there is no FDA-approved tirzepatide pill. Orforglipron, brand Foundayo, is an approved oral GLP-1 but a different molecule, as covered in [tirzepatide pills and oral tirzepatide](https://www.telosrx.com/blogs/glp1/tirzepatide-pills-oral-guide) and [what is semaglutide](https://www.telosrx.com/blogs/glp1/what-is-semaglutide-complete-guide). ## Choosing Between Formats Is a Clinical Conversation Format preference is real, but it is not the whole decision. Both brands carry a boxed warning about thyroid C-cell tumours seen in rodents, and both are contraindicated with a personal or family history of medullary thyroid carcinoma or MEN 2. Neither is for use in pregnancy. Common adverse effects are gastrointestinal: nausea, vomiting, diarrhea and constipation, usually worst during titration. Pancreatitis and gallbladder disease are less common but serious. Those apply to a Mounjaro injection, a Zepbound injection and a compounded tirzepatide injection alike, because the molecule is the same. Telos Rx is an online-first, asynchronous telehealth service: you complete a written intake and a licensed provider reviews it without a scheduled appointment. Any prescription is subject to medical approval by a licensed provider, and approval is not guaranteed. Starting from zero, read [how to start GLP-1 therapy](https://www.telosrx.com/blogs/glp1/how-to-start-glp1-therapy-step-by-step) and [how to get tirzepatide online safely](https://www.telosrx.com/blogs/glp1/how-to-get-tirzepatide-online-safely). ## Keep Reading - [What Is Tirzepatide?](https://www.telosrx.com/blogs/glp1/what-is-tirzepatide-complete-guide) - [Tirzepatide Cost Compared](https://www.telosrx.com/blogs/glp1/tirzepatide-cost-price-guide) - [Tirzepatide Titration Schedule](https://www.telosrx.com/blogs/glp1/tirzepatide-dosage-schedule) - [Injection Technique](https://www.telosrx.com/blogs/glp1/how-to-inject-tirzepatide) - [Tirzepatide Side Effects](https://www.telosrx.com/blogs/glp1/tirzepatide-side-effects-guide) - [Mounjaro vs Ozempic](https://www.telosrx.com/blogs/glp1/mounjaro-vs-ozempic-comparison) ## Frequently Asked Questions ### Is the Mounjaro pen the same as the Zepbound pen? The device design and the active molecule are the same, because both are tirzepatide from Eli Lilly. What differs is the approved indication. Mounjaro is approved for type 2 diabetes, Zepbound for chronic weight management and for moderate to severe obstructive sleep apnea in adults with obesity. ### How many doses are in a Mounjaro KwikPen? Four. The label describes the single-patient-use KwikPen as containing 2.4 mL, which provides four doses of 0.6 mL each. All four are the same strength, so a KwikPen labelled 60 mg per 2.4 mL delivers four 15 mg injections. The Zepbound KwikPen matches. ### Is a Mounjaro shot the same as a Zepbound shot? Chemically, yes. A Mounjaro shot and a Zepbound shot both deliver tirzepatide subcutaneously once a week. The difference is which population the FDA approved the brand for, and which strengths and devices a prescription specifies. A licensed provider decides which product and format suits an individual. ### Does compounded tirzepatide come in a pen? Compounded tirzepatide is usually supplied as a vial with separate syringes rather than a prefilled pen. Compounded preparations are not FDA-approved and are not required to match a brand device or concentration. What you receive is set by the prescription and the preparing pharmacy, not brand packaging. ### How is a dose measured from a compounded vial? You draw the prescribed volume into a syringe, which is why compounded prescriptions are usually written in millilitres or units as well as milligrams. That extra step is the tradeoff for a format prescribable between fixed brand strengths. Always follow the exact instruction on your pharmacy label. ### Do you have to refrigerate a KwikPen? The label directs storing an unopened KwikPen or multi-dose vial in a refrigerator at 2 to 8 degrees Celsius, and discarding it after 30 days at room temperature. After first use, discard it after 30 days from first use or four weekly doses, whichever comes first. _TelosRX is LegitScript-certified. Compounded medications are not FDA-approved and are prepared under federal compounding regulations. Approval is subject to evaluation by a licensed provider; approval is not guaranteed. Individual results vary. TelosRX operates as an online-first, asynchronous telehealth service._ Want to see which format fits how you would manage a weekly dose? Start with the [compounded tirzepatide page](https://www.telosrx.com/pages/tirzepatide), compare [microdosed tirzepatide](https://www.telosrx.com/pages/microdosed-tirzepatide), then complete the written intake at [start.telosrx.com](https://start.telosrx.com/start-online-visit/weightloss). A licensed provider reviews every request, and approval is not guaranteed. **Tags:** compounded tirzepatide, GLP-1, injection devices, KwikPen, Mounjaro, tirzepatide, weight management, Zepbound --- > Source: [Telos RX](https://www.telosrx.com/blogs/glp1/glp1-pens-vs-vials-guide)