Branded tirzepatide (Zepbound) starts at 2.5 mg once weekly and rises in 2.5 mg steps at least four weeks apart, to a 15 mg maximum.[1] On a compounded vial, the units you draw depend on its concentration: at 10 mg/mL, 2.5 mg is 25 units on a U-100 syringe. Your prescriber and pharmacy set the dose and strength.
Two numbers get confused in almost every conversation about compounded tirzepatide. The dose is a weight of drug, in milligrams, and it is what the prescriber orders. The units are a volume marking on an insulin syringe, and they mean nothing until you know how many milligrams of tirzepatide are dissolved in each milliliter of your vial. This page lays out the labeled Zepbound schedule, then converts every step to units at three common concentrations, and back again. It is a reading aid for a prescription you already have, not a dosing plan. The semaglutide version of this chart, built on the Wegovy ladder, is our compounded semaglutide dosage chart.
What is the tirzepatide titration schedule on the label?
The FDA label for Zepbound sets one starting dose for every indication: 2.5 mg injected under the skin once weekly for four weeks. After that the dose goes to 5 mg, and from there it can rise “in 2.5 mg increments, after at least 4 weeks on the current dose.” The recommended maintenance doses for weight reduction are 5, 10 or 15 mg once weekly; for obstructive sleep apnea they are 10 or 15 mg. The maximum is 15 mg once weekly.[1] The 2.5 mg step is a tolerability ramp, not a treatment dose, and the in-between steps (7.5 and 12.5 mg) are rungs on the way to a maintenance dose. Our GLP-1 dose ladder draws the same schedule beside Wegovy, Ozempic and Mounjaro.
| Step | Weekly dose | Earliest timing on the label | Role on the label |
|---|---|---|---|
| 1 | 2.5 mg | Weeks 1–4 | Starting dose only |
| 2 | 5 mg | Week 5 | Maintenance option (weight reduction) |
| 3 | 7.5 mg | Week 9 at the earliest | Escalation step |
| 4 | 10 mg | Week 13 at the earliest | Maintenance option (weight reduction, sleep apnea) |
| 5 | 12.5 mg | Week 17 at the earliest | Escalation step |
| 6 | 15 mg | Week 21 at the earliest | Maintenance option; labeled maximum |
Compounded tirzepatide has no label of its own, so nothing obliges a prescriber to follow this ladder. It is the schedule the trials tested, so it is the natural reference point, but a prescriber can hold a step longer, step down, or use a dose between rungs. That decision belongs to the prescriber and you, and the pharmacy’s job is to put a known number of milligrams in each milliliter.
Why does a Zepbound dose never change volume, while a compounded dose does?
This is the detail most charts miss. Lilly makes a different product for every dose, and every product holds that dose in the same volume. Each single-dose Zepbound vial contains its dose in 0.5 mL, from “2.5 mg/0.5 mL” up to “15 mg/0.5 mL.” The multi-dose vials and KwikPens hold four doses each, at 0.6 mL per dose; the 2.5 mg version is 10 mg in 2.4 mL (4.17 mg/mL), and the 15 mg version is 60 mg in 2.4 mL (25 mg/mL).[1] So on the branded product, when your dose goes up, the concentration goes up and the volume stays put.
A compounded vial usually works the other way. One vial at one concentration often has to cover several dose steps, so when the dose goes up, the volume you draw goes up. That is why a compounded prescription is written in units, and it is why the same number of units can mean a different dose after a refill if the pharmacy, or the concentration, changes.
| Dose | Zepbound single-dose vial | Zepbound multi-dose vial or KwikPen (per dose) | Compounded vial at 10 mg/mL |
|---|---|---|---|
| 2.5 mg | 0.5 mL (5 mg/mL) | 0.6 mL (4.17 mg/mL) | 0.25 mL = 25 units |
| 5 mg | 0.5 mL (10 mg/mL) | 0.6 mL (8.33 mg/mL) | 0.5 mL = 50 units |
| 7.5 mg | 0.5 mL (15 mg/mL) | 0.6 mL (12.5 mg/mL) | 0.75 mL = 75 units |
| 10 mg | 0.5 mL (20 mg/mL) | 0.6 mL (16.7 mg/mL) | 1.0 mL = 100 units |
| 12.5 mg | 0.5 mL (25 mg/mL) | 0.6 mL (20.8 mg/mL) | 1.25 mL = 125 units |
| 15 mg | 0.5 mL (30 mg/mL) | 0.6 mL (25 mg/mL) | 1.5 mL = 150 units |
How many units is each tirzepatide dose at 5, 10 and 20 mg/mL?
The conversion is one line: units = dose in mg ÷ concentration in mg/mL × 100. A U-100 insulin syringe holds 100 units per milliliter, so each unit is 0.01 mL. The table below runs that arithmetic for every labeled step at three concentrations, chosen to show how far the answer moves. They are examples. Compounding pharmacies make tirzepatide at many strengths, and the only concentration that matters is the one printed on your vial.
| Weekly dose | At 5 mg/mL | At 10 mg/mL | At 20 mg/mL |
|---|---|---|---|
| 2.5 mg | 50 units (0.5 mL) | 25 units (0.25 mL) | 12.5 units (0.125 mL) |
| 5 mg | 100 units (1.0 mL) | 50 units (0.5 mL) | 25 units (0.25 mL) |
| 7.5 mg | 150 units (1.5 mL)* | 75 units (0.75 mL) | 37.5 units (0.375 mL) |
| 10 mg | 200 units (2.0 mL)* | 100 units (1.0 mL) | 50 units (0.5 mL) |
| 12.5 mg | 250 units (2.5 mL)* | 125 units (1.25 mL)* | 62.5 units (0.625 mL) |
| 15 mg | 300 units (3.0 mL)* | 150 units (1.5 mL)* | 75 units (0.75 mL) |
Half-unit answers such as 12.5 or 37.5 units are real results of the math, and they are hard to measure on a syringe marked in 1- or 2-unit lines. If your prescription lands on one, ask the prescriber or pharmacist how they want it drawn, or whether a different concentration makes the dose easier to measure. Our reconstitution calculator does the same arithmetic for any concentration.
How many mg is 25, 50 or 75 units of tirzepatide?
Read the other way, the formula is mg = units ÷ 100 × concentration. This is the question behind searches like “50 units of tirzepatide”: 50 units is half a milliliter, and half a milliliter is 2.5, 5 or 10 mg depending on the vial. Without the concentration, a number of units is not a dose.
| Units drawn (U-100) | Volume | At 5 mg/mL | At 10 mg/mL | At 20 mg/mL |
|---|---|---|---|---|
| 10 units | 0.10 mL | 0.5 mg | 1 mg | 2 mg |
| 25 units | 0.25 mL | 1.25 mg | 2.5 mg | 5 mg |
| 50 units | 0.50 mL | 2.5 mg | 5 mg | 10 mg |
| 60 units | 0.60 mL | 3 mg | 6 mg | 12 mg |
| 75 units | 0.75 mL | 3.75 mg | 7.5 mg | 15 mg |
| 100 units | 1.00 mL | 5 mg | 10 mg | 20 mg (above the 15 mg labeled maximum) |
What dosing errors has FDA seen with compounded GLP-1s?
The errors FDA has documented come straight from the gap between units and milligrams. In a July 2024 alert about compounded semaglutide, the agency described patients who drew 50 units when they had been told to draw 5, prescribers who wrote 25 units when they meant 5 and 20 units when they meant 2, and patients who injected “five to 20 times more than the intended dose.” Some were hospitalized with vomiting, dehydration, pancreatitis or gallstones.[4] FDA’s running page on unapproved GLP-1s, current as of October 1, 2026, counts more than 730 adverse-event reports tied to compounded tirzepatide and 990 tied to compounded semaglutide as of May 31, 2026. It also notes reports from patients prescribed compounded products “in doses beyond what is in the FDA-approved drug label.”[5]
How long does a compounded tirzepatide vial last at each dose?
Divide the total milligrams in the vial by your weekly dose. A vial with 2 mL at 10 mg/mL holds 20 mg in total. The catch is the beyond-use date: a multi-dose compounded vial carries a date set by the pharmacy, and it can arrive before the drug runs out. Discard the vial on that date even if some is left. Storage and beyond-use dates are covered in our guide to how to store peptides.
| Weekly dose | Doses from a 20 mg vial (2 mL at 10 mg/mL) | Left over |
|---|---|---|
| 2.5 mg | 8 weekly doses | None |
| 5 mg | 4 weekly doses | None |
| 7.5 mg | 2 weekly doses | 5 mg |
| 10 mg | 2 weekly doses | None |
| 12.5 mg | 1 weekly dose | 7.5 mg |
| 15 mg | 1 weekly dose | 5 mg |
What if you miss a dose, or a step makes you too sick?
The Zepbound label gives two rules that prescribers often carry over to compounded tirzepatide. A missed dose should be taken “as soon as possible within 4 days (96 hours)”; if more than four days have passed, skip it and take the next dose on the usual day. The injection day can move, as long as doses are at least 3 days (72 hours) apart. And if a maintenance dose is not tolerated, the label says to “consider a lower maintenance dosage.”[1] Stepping back down is a normal part of titration. Nausea, vomiting and diarrhea are most common in the weeks after a dose increase; our Zepbound side effects guide covers the timeline. Whether to restart at the same dose after several missed weeks is a question for your prescriber, because tolerance to the GI effects fades.
Which tirzepatide dose produced which weight loss in the trials?
The maintenance doses on the label are the three that SURMOUNT-1 tested. In that 72-week trial of 2,539 adults with obesity or overweight, mean weight change was −15.0% at 5 mg, −19.5% at 10 mg and −20.9% at 15 mg, against −3.1% with placebo (P < 0.001 for each dose).[2] The step from 10 to 15 mg added less than the step from 5 to 10 mg, which is one reason many patients stay at a middle dose. SURMOUNT-4 tested what happens after the climb: people who had lost 20.9% over a 36-week lead-in and stayed on tirzepatide lost a further 5.5%, while those switched to placebo regained 14.0% (difference −19.4%, 95% CI −21.2% to −17.7%).[3] These are results for branded tirzepatide made under Lilly’s process. No compounded product has been tested against them. For how long-term dosing is handled, see GLP-1 maintenance dosing.
| Arm (SURMOUNT-1, 72 weeks) | Mean weight change | 95% CI |
|---|---|---|
| Placebo | −3.1% | −4.3 to −1.9 |
| Tirzepatide 5 mg | −15.0% | −15.9 to −14.2 |
| Tirzepatide 10 mg | −19.5% | −20.4 to −18.5 |
| Tirzepatide 15 mg | −20.9% | −21.8 to −19.9 |
Is compounded tirzepatide still allowed in 2026?
Only narrowly. FDA declared the tirzepatide shortage resolved on December 19, 2024. The grace period for state-licensed 503A pharmacies ended February 18, 2025, and the one for 503B outsourcing facilities ended March 19, 2025. A 503A pharmacy may still compound tirzepatide for an individual patient when the prescriber documents a clinically significant difference for that patient, such as a different strength or a removed ingredient.[6] In February 2026 FDA said it intends to restrict tirzepatide and other GLP-1 ingredients bound for mass-marketed compounded drugs, and that sellers may not call compounded products generic versions of, or the same as, approved drugs.[7] The full picture is in our compounded versus branded GLP-1 explainer.
What does each route cost?
Price depends on route more than dose. Branded Zepbound self-pay is priced by dose step, while many compounded programs charge one monthly price across doses. Our tirzepatide cost guide breaks down each route, and cheapest tirzepatide covers what a low headline price can leave out. To compare telehealth services side by side, see tirzepatide providers or, if price comes first, the lowest published tirzepatide prices.
The bottom line
The label gives the milligrams: 2.5 mg to start, 2.5 mg steps at least four weeks apart, and a 15 mg ceiling. A compounded vial adds a second number, its concentration, and only the two together tell you how many units to draw. Write both on your prescription, check them against the vial each refill, and treat any mismatch as a reason to call the pharmacy rather than to guess.