Tirzepatide Dose Calculator

Compounded tirzepatide comes as a liquid in a vial with a concentration printed on the label, in milligrams per milliliter. Doses are drawn with a U-100 insulin syringe, whose markings are a volume scale: 100 units is 1 mL, so each unit is 0.01 mL. Converting a dose is one line of arithmetic: divide the dose in mg by the concentration in mg/mL to get milliliters, then multiply by 100 to get units.

The same draw holds a different amount of medication at a different concentration, which is the whole reason the concentration field comes first. 25 units is 2.5 mg from a 10 mg/mL vial and 5 mg from a 20 mg/mL vial. If you were switched to a new vial, a new pharmacy, or a different strength, re-run the number rather than reusing last month's units.

It does not choose or adjust a dose. Dose escalation for these medications follows the label ladder and your prescriber's judgement; the dose chips on the calculator are the label strengths for reference only. It also does not apply to the branded pens: Zepbound, Mounjaro, Wegovy, and Ozempic pens deliver a set dose without any unit conversion, and the Zepbound single-dose vials are drawn in full as their instructions describe.

Compounded GLP-1 products are not FDA-approved, and the FDA has received reports of dosing errors with compounded injections, including confusion between units and milligrams. Those reports are the reason this page exists: check the math, then confirm it with the pharmacy that dispensed your vial. Compounded semaglutide and tirzepatide are a US-only option.

The same label ladder at the concentrations pharmacies most often dispense. Cells over 100 units do not fit a single 1 mL insulin syringe. Read the mg/mL on your own vial and use that column; the calculator above handles any other concentration.

The units are the easy part to lose track of. What matters over a course of treatment is the record: which mg dose you took, on which day, in which injection site, and what happened afterwards. GlucoPal logs compounded tirzepatide and semaglutide by mg dose alongside the branded pens, sends a reminder for the weekly draw, keeps an injection-site rotation map, and turns the history into a doctor-ready PDF for your next appointment.

It is free to download and use, with no account required, and it keeps this calculator company: work out the draw here, log the dose there.

The Zepbound label starts at 2.5 mg once weekly for four weeks, then 5 mg, with optional steps of 2.5 mg at intervals of at least four weeks up to 15 mg. Compounded tirzepatide prescriptions typically follow the same ladder. At 10 mg/mL the six strengths are 25, 50, 75, 100, 125, and 150 units; at 17 mg/mL they are about 14.7, 29.4, 44.1, 58.8, 73.5, and 88.2 units; at 20 mg/mL, 12.5, 25, 37.5, 50, 62.5, and 75 units.

When a dose steps up, the units step up with it at the same concentration, and a new vial at a different concentration resets the whole table. The calculator's ladder table re-computes for whatever concentration you enter, so a step-up is a matter of reading the next row, not re-doing the arithmetic.

The FDA-approved Zepbound vials sold through LillyDirect are single-dose: 2.5 mg, 5 mg, 7.5 mg, 10 mg, 12.5 mg, and 15 mg, each in 0.5 mL. Because the volume is the same for every strength, the draw is always the full vial, 50 units on an insulin syringe, and the strength is set by which vial you were dispensed. The instructions for use cover the draw; there is nothing to convert.

The label describes the vials as single-dose with no preservative, to be discarded after use. That is why this page does not include a vial-splitting tool: the arithmetic would be easy, but it would be arithmetic for something the label says not to do.

Some pharmacies dispense tirzepatide as a lyophilized powder with a stated milligram strength and written reconstitution instructions, and the concentration only exists once the bacteriostatic water is added. Switch the calculator to “I mix a powder vial” and enter the mg on the vial and the mL of water the instructions specify: 30 mg in 3 mL is 10 mg/mL, 30 mg in 1.5 mL is 20 mg/mL. Adding more water lowers the concentration and raises the units per dose; it never changes the dose itself. This mode is for a prescription vial with instructions from the dispensing pharmacy, not for research-use products, which are not medicines.

Write the resulting concentration on the vial. The next time you draw, it is the number you need, and a vial reconstituted differently from the last one is the most common way the same units end up holding a different dose.