Tirzepatide Reconstitution Calculator
Enter your tirzepatide vial size, the bacteriostatic water you added, and your provider-directed dose. Get the exact insulin-syringe units to draw — live on the syringe below — plus the FDA-label titration schedules for reference. It’s the same math built into the PeptideWiz app.
Common vial sizes
Common provider-directed doses
To draw a dose of 2.5 mg, pull the plunger to 50.0 units.
Not medical advice. This calculator performs arithmetic on the numbers you enter. It does not recommend a dose, confirm that tirzepatide or any protocol is safe or appropriate for you, or replace your provider. Always verify everything with a licensed medical professional.
Tirzepatide mixing quick-reference
The water volume you add sets the concentration — it never changes the dose itself, only how big the draw is on the syringe. Here’s how a 10 mg vial reads on a U-100 insulin syringe at three common water volumes:
| Water added | Concentration | 2.5 mg dose | 5 mg dose | 7.5 mg dose |
|---|---|---|---|---|
| 1 mL | 10,000 mcg/mL | 25 units | 50 units | 75 units |
| 2 mL | 5,000 mcg/mL | 50 units | 100 units | 150 units* |
| 3 mL | 3,333 mcg/mL | 75 units | 150 units* | 225 units* |
* Exceeds a 1 mL (100-unit) U-100 syringe. Higher doses may need a split draw or less water (a higher concentration keeps the draw smaller) — the calculator warns whenever a draw overfills your syringe. Using a 5, 15, or 30 mg vial? Tap the preset above — the calculator redoes every number instantly.
Tirzepatide titration schedules (FDA label, for reference)
Branded tirzepatide is titrated stepwise so the body can adjust. These are the FDA-approved schedules for Zepbound and Mounjaro, shown for reference only — compounded tirzepatide dosing varies, and your prescriber’s plan always takes precedence.
Zepbound (weight management) — once weekly
Increase in 2.5 mg increments after at least 4 weeks at a dose; maintenance doses are 5, 10, or 15 mg.
| Weeks | Weekly dose | Units at 5,000 mcg/mL |
|---|---|---|
| 1–4 | 2.5 mg (starting dose, not for maintenance) | 50 units |
| 5+ | 5 mg (maintenance option) | 100 units |
| If needed, after ≥4 weeks | 7.5 mg | 150 units |
| If needed, after ≥4 weeks | 10 mg (maintenance option) | 200 units |
| If needed, after ≥4 weeks | 12.5 mg | 250 units |
| Maximum | 15 mg (maintenance option) | 300 units |
Mounjaro (type 2 diabetes) — once weekly
Increase in 2.5 mg increments after at least 4 weeks, only as needed.
| Weeks | Weekly dose | Units at 5,000 mcg/mL |
|---|---|---|
| 1–4 | 2.5 mg | 50 units |
| 5+ | 5 mg | 100 units |
| If needed, after ≥4 weeks | 7.5 mg | 150 units |
| If needed, after ≥4 weeks | 10 mg | 200 units |
| If needed, after ≥4 weeks | 12.5 mg | 250 units |
| Maximum | 15 mg | 300 units |
The units column assumes a 10 mg vial with 2 mL of bacteriostatic water (5,000 mcg/mL). At this concentration, doses above 5 mg exceed a single 1 mL U-100 syringe — a higher concentration (less water) keeps the draw smaller; the calculator warns when a draw exceeds your syringe. A different vial or water volume changes every unit figure — use the calculator above with your own numbers.
How to reconstitute a tirzepatide vial
- Gather supplies. The lyophilized tirzepatide vial, bacteriostatic water, a sterile mixing syringe, alcohol wipes, and your insulin syringes.
- Sanitize. Wash your hands and wipe both vial stoppers with a fresh alcohol wipe.
- Draw the water. Pull your chosen volume (for example 2 mL) into the mixing syringe — that volume sets the concentration, so enter the same number in the calculator above.
- Add it slowly. Let the water run gently down the inside wall of the vial. Don’t jet it straight onto the powder.
- Swirl, don’t shake. Gently swirl until the solution is completely clear — shaking can degrade peptides.
- Label and refrigerate. Write the date and concentration on the vial, store it cold, and track doses, remaining volume, and the reconstitution date in the PeptideWiz app.
Full walkthrough: How to reconstitute peptides, step by step →
How the calculation works
vial (mcg) ÷ water (mL)
How much tirzepatide is in every millilitre after reconstitution.
dose (mcg) ÷ concentration
The millilitres that contain exactly your dose.
mL × 100
A U-100 insulin syringe holds 100 units per millilitre.
Worked example: a 10 mg vial (10,000 mcg) with 2 mL of water gives 5,000 mcg/mL. A 2.5 mg (2,500 mcg) dose is 2,500 ÷ 5,000 = 0.5 mL, and 0.5 × 100 = 50 units — with 4 such doses in the vial.
Frequently asked questions
How much bacteriostatic water should I add to a 10 mg tirzepatide vial?
There’s no single correct volume — water only sets the concentration, not the dose. 2 mL gives 5,000 mcg/mL, so a 2.5 mg dose is a clean 50-unit draw. Pick a volume that makes your provider-directed dose land on easy-to-read syringe marks; the calculator lets you compare instantly.
How many units is 2.5 mg of tirzepatide?
It depends entirely on your vial’s concentration. At 5,000 mcg/mL (10 mg vial + 2 mL water) it’s 50 units; at 10,000 mcg/mL (same vial + 1 mL) it’s 25 units. Never reuse someone else’s unit figure — calculate from your own vial and water volume.
What is the tirzepatide titration schedule?
The FDA-approved schedule for Zepbound (weight management) starts at 2.5 mg once weekly for 4 weeks — a starting dose, not for maintenance — then steps to 5 mg, and may increase in 2.5 mg increments after at least 4 weeks at a dose; maintenance doses are 5, 10, or 15 mg, with a 15 mg weekly maximum. Mounjaro (type 2 diabetes) starts at 2.5 mg weekly for 4 weeks, then 5 mg, increasing in 2.5 mg increments after at least 4 weeks only as needed, to a 15 mg maximum. These label schedules are shown for reference only — your prescriber sets your actual plan.
Is this calculator medical advice?
No. It is an educational arithmetic tool. It does not recommend a dose, verify that tirzepatide or any protocol is appropriate for you, or replace guidance from a licensed medical provider.
Track your tirzepatide protocol in the PeptideWiz app →
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