ToolsDose math · Compounded vials
Tirzepatide Dose ↔ Unit Converter
mg ↔ units on a U-100 syringe, for compounded vials
Compounded tirzepatide comes in a multi-dose vial you reconstitute yourself and draw with an insulin syringe — so there is no fixed answer to “how many units?” until you know the vial’s concentration. This tool does that one piece of arithmetic: it takes the milligrams in the vial and the millilitres of bacteriostatic water you added to get a concentration in mg/mL, then converts a dose in milligrams to units (or units back to milligrams). It is a math converter, not a dose recommendation.
Read before you use this
This is a unit-conversion calculator only — not a dose recommendation and not medical advice. It does not tell you what dose to take, how to titrate, or whether compounded tirzepatide is appropriate for you. The FDA-approved brand products (Zepbound and Mounjaro) are fixed-dose pens and single-dose vials and are never measured in “units” — this converter applies only to compounded multi-dose vials drawn with an insulin syringe. Getting this conversion wrong has caused people to inject ten-fold overdoses. Confirm the result against your actual vial label and with your prescribing clinician and the compounding pharmacy before drawing or injecting anything. Tirzepatide is prescription-only.
Draw to
25units
That is 0.25 mL on a U-100 syringe, at a concentration of 10 mg/mL. Double-check against your vial and your clinician before drawing anything.
- Concentration
- 10
- mg / mL (vial ÷ BAC water)
- Volume to draw
- 0.25
- mL
- Units
- 25
- units (U-100)
How it is calculated. Concentration = vial total mg ÷ BAC water mL. On a U-100 insulin syringe, 100 units = 1 mL. For mg → units, units = (dose mg ÷ concentration) × 100; the reverse is mg = (units ÷ 100) × concentration. Worked example: a 10 mg vial reconstituted with 1 mL = 10 mg/mL; a 2.5 mg dose = 0.25 mL = 25 units.
Understand the dosing math before you draw
The number is the easy part. Why “units” depend entirely on concentration, how brand dosing differs, and the real-world risks of compounded vials are the parts that matter — read these next:
This converter is informational and not medical advice. It performs simple arithmetic (concentration = vial mg ÷ BAC water mL; units = dose ÷ concentration × 100) and makes no judgment about what dose is safe or appropriate for you. Concentrations are not standardized across compounding pharmacies or even across vials, and an error here can cause a large overdose — always verify against your vial label and your prescribing clinician. Tirzepatide is available by prescription after clinician review.