Tirzepatide Reconstitution Calculator
Tirzepatide milligrams and syringe units are not interchangeable: units measure volume and depend on the labeled concentration. Approved tirzepatide presentations have product-specific instructions; they should not be treated as research powder to mix. This calculator illustrates concentration arithmetic, not a mixing prescription.
This is a unit converter. It converts an amount you already have into volume and syringe units. It does not tell you what to take, and it is educational only — not medical advice. Confirm every amount with your clinician and your product label.
Example mixes to try the converter
Examples only — not recommended amounts. These fill in a vial size and diluent volume only — never an amount to inject. Enter the dose your clinician gave you yourself.
Calculator inputs
Total compound in the vial.
Volume of bacteriostatic water you reconstitute with.
Enter your target dose as a number.
U-100 = 100 units per mL (standard). U-40 = 40 units per mL.
- Enter your target dose as a number.
Tirzepatide concentration reference (mg/mL)
What each vial size becomes at common bacteriostatic water volumes.
| Vial | + 1 mL | + 2 mL | + 3 mL | + 5 mL |
|---|---|---|---|---|
| 10 mg | 10.00 mg/mL | 5.00 mg/mL | 3.33 mg/mL | 2.00 mg/mL |
| 15 mg | 15.00 mg/mL | 7.50 mg/mL | 5.00 mg/mL | 3.00 mg/mL |
| 20 mg | 20.00 mg/mL | 10.00 mg/mL | 6.67 mg/mL | 4.00 mg/mL |
| 30 mg | 30.00 mg/mL | 15.00 mg/mL | 10.00 mg/mL | 6.00 mg/mL |
| 40 mg | 40.00 mg/mL | 20.00 mg/mL | 13.33 mg/mL | 8.00 mg/mL |
| 60 mg | 60.00 mg/mL | 30.00 mg/mL | 20.00 mg/mL | 12.00 mg/mL |
Tirzepatide dosing evidence
FDA-labeled dosing context. DoseRoutine performs arithmetic; it does not choose or recommend a dose. Your prescriber decides yours.
| Phase | Dose | Frequency | Notes |
|---|---|---|---|
| Initiation | 2.5 mg | Once weekly for 4 weeks | Initiation dose; not intended as maintenance. |
| Escalation | +2.5 mg steps | No sooner than every 4 weeks | Escalation depends on response and tolerability. |
| Maintenance | 5, 10, or 15 mg | Once weekly | Weight-management maintenance options in the current label. |
Sources
- Zepbound prescribing information — U.S. Food and Drug Administration
What trips people up
- Mixing 1 mL of BAC water per 10 mg of tirzepatide gives a tidy 10 mg/mL: 2.5 mg = 25 units, 5 mg = 50 units.
- Approved tirzepatide pens and vial presentations have their own instructions. Do not add diluent to a ready-to-use product or assume every vial requires reconstitution.
- The labeled schedule escalates no faster than every 4 weeks — most severe GI side effects in trials came from rushed titration. Compounded or research-grade tirzepatide is not FDA-approved, and obtaining it without a prescription may be illegal.
- Tirzepatide is a GLP-1/GIP dual agonist and slows gastric emptying, which can change how quickly oral medications are absorbed.
How the math works
- Concentration (mg/mL) = vial mg ÷ bacteriostatic water mL.
- Volume per dose (mL) = dose mg ÷ concentration.
- Syringe units = volume × 100 on a U-100 syringe, or × 40 on a U-40 syringe.
- Doses per vial = vial mg ÷ dose mg. Water volume never changes this number.
Tirzepatide calculator FAQ
How much BAC water do I add to a 30 mg tirzepatide vial?
Only the dispensing pharmacist or the exact product instructions can establish a preparation method. As a hypothetical calculation, 30 mg divided by 3 mL equals 10 mg/mL. This is not an instruction to add water to a tirzepatide product.
How many units is 5 mg of tirzepatide?
At 10 mg/mL it is 0.5 mL = 50 units on a U-100 syringe. At 20 mg/mL (30 mg + 1.5 mL) the same dose is 25 units. Concentration is the only thing that decides this.
How long does reconstituted tirzepatide last?
Use the exact product or pharmacy beyond-use and storage instructions. Stability depends on formulation, container, preparation, and handling. Neither this calculator nor the use of bacteriostatic water establishes a universal 28–30 day lifetime.
What's the difference between tirzepatide and semaglutide dosing?
They are not interchangeable. Tirzepatide runs 2.5–15 mg weekly; semaglutide runs 0.25–2.4 mg weekly. Do not convert one to the other by ratio — switch under clinical supervision.
Educational tool only — not medical advice. Verify every dose with your prescriber and follow sterile technique. See our medical disclaimer.
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Reviewed by the DoseRoutine editorial team. Last reviewed .