Tirzepatide 30 mg reconstitution calculator
How much bac water for tirzepatide 30 mg?
There’s no single right amount: the water sets the strength, not how much tirzepatide is in the vial, so use the volume on your pharmacy’s instructions. For example, 1.5 mL makes 20 mg/mL and 2 mL makes 15 mg/mL; the table below shows what each volume means on a U-100 syringe.
Your tirzepatide vial
Syringe
1 mL · 2-unit marks
Work backwards
Find the water for a given reading in units.
Enter your numbers to see the result.
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This is arithmetic, not medical advice. Confirm with your prescriber or pharmacist.
How our calculator worksAdvanced
Vial capacityOptional
The volume printed on the vial or its box, not the mg. We’ll tell you if the water won’t fit.
What each volume makes
| Water | Strength | Each unit | 1 mg is |
|---|---|---|---|
| 1.5 mL | 20 mg/mL | 200 mcg | 5 units |
| 2 mL | 15 mg/mL | 150 mcg | 6.7 units |
| 3 mL | 10 mg/mL | 100 mcg | 10 units |
Examples; use the volume on your pharmacy’s instructions. Units are on a U-100 syringe: 100 units = 1 mL.
About the 30 mg vial
A labeled 30 mg vial is already mixed
Zepbound and Mounjaro both come in a 30 mg multi-dose vial that is a ready-made liquid: 30 mg in 2.4 mL (12.5 mg/mL), labeled as four doses of 0.6 mL (Zepbound label, Mounjaro label). If your vial reads “30 mg/2.4 mL”, don’t add bacteriostatic water. Extra liquid dilutes it, so 0.6 mL would no longer hold the labeled amount. The label says to measure each dose with a syringe that can measure 0.6 mL, such as a 1 mL syringe, and to use a new syringe and needle every time. Follow your prescriber.
Units don't carry over from Zepbound or Mounjaro
Each unit on a U-100 syringe is 0.01 mL, so what it holds depends on the strength. In the labeled 30 mg/2.4 mL vial (12.5 mg/mL), a unit holds 0.125 mg. The labeled single-dose vials hold 0.5 mL each, at 5 to 30 mg/mL (Zepbound label). A mixed 30 mg vial holds 0.2 mg per unit with 1.5 mL of water, 0.15 mg with 2 mL and 0.1 mg with 3 mL. None of these is 12.5 mg/mL, so a number of units from a branded vial doesn’t transfer. If you switch between products, work out your units again from the mg your prescriber gave you, and check them with your pharmacist.
A 30 mg vial you mix isn't FDA-approved
FDA-approved tirzepatide (Zepbound and Mounjaro) is supplied as a ready-made solution in pens and vials, so a 30 mg vial that needs water is compounded or unapproved (Zepbound label, Mounjaro label). Compounded drugs aren’t FDA-approved: the FDA doesn’t check their safety, effectiveness or quality before they’re marketed (FDA). The FDA has received reports of dosing errors with compounded injectable semaglutide, from people measuring their own doses and from some health professionals miscalculating them (FDA). Use the strength printed on your pharmacy’s label, and confirm your units with the pharmacist.
More draws per vial, so check the date
A 30 mg vial holds three times what a 10 mg vial holds, so the same prescription takes three times as many draws and the vial stays in use longer. The calculator above shows how many doses of your prescribed amount the vial holds. Even the labeled 30 mg multi-dose vial is thrown away 30 days after first use, after 4 weekly doses, or after 30 days in total at room temperature, even if medicine is left (Zepbound label). A compounded vial follows the beyond-use date on your pharmacy’s label instead. Count your draws against that date before you mix, and ask the pharmacist how long the vial lasts once mixed.
Sources for these notes
- ZEPBOUND (tirzepatide) injection, prescribing informationDailyMed, U.S. National Library of Medicine, 2026 (opens in a new tab)
- MOUNJARO (tirzepatide) injection, prescribing informationDailyMed, U.S. National Library of Medicine, 2026 (opens in a new tab)
- ZEPBOUND (tirzepatide) injection, prescribing informationDailyMed, U.S. National Library of Medicine, 2026 (opens in a new tab)
- Compounding and the FDA: Questions and AnswersU.S. Food and Drug Administration, 2025 (opens in a new tab)
- FDA’s Concerns with Unapproved GLP-1 Drugs Used for Weight LossU.S. Food and Drug Administration, 2026 (opens in a new tab)
- ZEPBOUND (tirzepatide) injection, prescribing informationDailyMed, U.S. National Library of Medicine, 2026 (opens in a new tab)
About tirzepatide
US regulatory status
FDA-approved prescription drug
Eli Lilly makes both FDA-approved products: Mounjaro, for type 2 diabetes (adults and children 10 and older) and to lower heart risk in high-risk adults with type 2 diabetes, and Zepbound, for long-term weight management and for sleep apnea with obesity in adults. Compounded tirzepatide is not FDA-approved: the FDA declared the shortage resolved on December 19, 2024, and in April 2026 proposed excluding it from the list outsourcing facilities may compound from. The FDA has also warned sellers of “research use only” tirzepatide.
As of
Sources (6)
- MOUNJARO (tirzepatide) injection, prescribing informationDailyMed, U.S. National Library of Medicine, 2026 (opens in a new tab)
- ZEPBOUND (tirzepatide) injection, prescribing informationDailyMed, U.S. National Library of Medicine, 2026 (opens in a new tab)
- FDA clarifies policies for compounders as national GLP-1 supply begins to stabilizeU.S. Food and Drug Administration, 2026 (opens in a new tab)
- FDA Proposes to Exclude Semaglutide, Tirzepatide, and Liraglutide on 503B Bulks ListU.S. Food and Drug Administration, 2026 (opens in a new tab)
- FDA’s Concerns with Unapproved GLP-1 Drugs Used for Weight LossU.S. Food and Drug Administration, 2026 (opens in a new tab)
- Warning letter: TXP Innovations LLC dba Tex Peptides (MARCS-CMS 735067)U.S. Food and Drug Administration, 2026 (opens in a new tab)
How this tirzepatide calculator works
This tirzepatide reconstitution calculator starts from the 30 mg in your vial. Add the water you mix it with and the dose your prescriber gave you; it divides the mg by the mL to get the strength, then turns your dose into mL and units on a 30, 50 or 100-unit syringe.
Peptinote never suggests a dose or a water volume. The example volumes are there to make the math easy to check, not as advice. For the full method, see the peptide calculator.
Questions people ask
How much bacteriostatic water do I add to 30 mg of tirzepatide?
There’s no single right amount: use the volume on your pharmacy’s instructions. The water only sets the strength; the vial still holds 30 mg however much you add. With 1.5 mL it’s 20 mg/mL (200 mcg per unit), with 2 mL 15 mg/mL (150 mcg per unit) and with 3 mL 10 mg/mL (100 mcg per unit). Enter your volume and prescribed dose above to get the units.
How much bac water goes into 30 mg of tirzepatide?
Whatever volume you add, only the strength changes; the vial still holds 30 mg. More water spreads it out, so each unit holds less and the same dose takes more units: easier to measure, but more liquid to inject. Going from 1.5 mL to 3 mL takes each unit from 200 mcg to 100 mcg. Check the volume on your pharmacy’s instructions first.
How much bacteriostatic water do I use to reconstitute tirzepatide?
Use the volume your pharmacy specifies, and never more than the vial itself can hold (its size in mL, not the 30 mg on the label). If you weren’t given a volume, ask the pharmacist who dispensed the vial before mixing. For reference, the bac water calculator shows the arithmetic: water (mL) = vial mg × units ÷ (dose mg × 100).
How do I reconstitute tirzepatide 30 mg?
Wipe both stoppers with alcohol and let them dry. Draw the volume of bacteriostatic water your pharmacy specifies into a new syringe, add it slowly down the inside of the vial, then swirl gently until clear; don’t shake. Label it with the strength: 30 mg in 1.5 mL is 20 mg/mL. Full steps: how to reconstitute peptides.
What are the steps to reconstitute tirzepatide 30 mg?
Mixing your tirzepatide 30 mg vial takes the bacteriostatic water your pharmacy specifies and a new sterile syringe. Add the water slowly against the glass and swirl, never shake, until the liquid is clear. If it stays cloudy or has particles, don’t use it; call your pharmacy. Then write the strength and date on the vial and store it as the label says (how to store peptides).
Is there a peptide calculator for tirzepatide reconstitution?
This page is the tirzepatide 30 mg reconstitution calculator. Enter the water you add (or tap an example volume) and your prescribed dose, and it shows the units to draw on a 30, 50 or 100-unit syringe, the strength, and the doses in the vial, with every step of the math. It never suggests a dose.
Can Peptinote tell me how many units to take?
No. Peptinote never suggests a dose. Enter the dose your prescriber gave you, and the calculator shows how to measure it: the units, the mL and where the line sits on your syringe, with every step of the math. If you aren’t sure what your dose is, ask your prescriber or pharmacist before drawing anything. How our calculator works.
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Every result is plain arithmetic from formulas we publish in full and check with automated tests. Peptinote doesn’t suggest doses and never sells or links to sellers of peptides.