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Mounjaro (tirzepatide) reconstitution calculator

Mounjaro is a pen, but compounded or vialed tirzepatide (the same molecule) is reconstituted from powder. Enter the vial mg, bac water, and dose for the exact units, mL, and doses per vial.

Peptide

GLP-1/GIP (Mounjaro/Zepbound molecule; also compounded).

Vial strength (mg powder)

Bac water added (mL)

Target dose (mg)

Syringe

Vial cost (optional, for cost/dose)

Draw per dose10 units

Exact10 units · 0.1 mL

Concentration2.5 mg/mL

Doses per vial20

Reverse: someone gave you units — what mg is that?

= — at your mix above

"Units" are a volume marking, not a drug amount — the same units = a different mg every time the vial is mixed differently.

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FAQ

How many units is my dose?

Units are a volume marking on the syringe, not a drug amount — on a U-100 syringe, 100 units = 1 mL. The units for any dose depend entirely on how the vial was reconstituted (mg of powder ÷ mL of bacteriostatic water). Enter your numbers above and the calculator gives the exact units.

How much bacteriostatic water should I add?

There's no single right amount — more water makes the solution more dilute (easier to draw, larger volume per dose) and less water makes it more concentrated. Pick a volume, enter it above, and the calculator shows the resulting concentration, units per dose, and doses per vial so you can choose a readable draw.

Other calculators

Sources

This tool converts the numbers you enter — it never recommends a dose. Its constants are cited below; the warnings are arithmetic checks, not clinical limits.

Syringe "units" are a volume marking, not a drug amount: a U-100 syringe reads 100 units = 1 mL (U-40 = 40 units/mL). The calculator converts mg ↔ mL ↔ units on this standard — it never assumes units equal mg.Standard insulin concentration, U-100 = 100 units/mL (PMC5505430) ↗
The volume to draw is (drug ordered ÷ drug available) × the vial's total mL — i.e. dose ÷ concentration, where concentration (mg/mL) = vial mg ÷ bacteriostatic water mL. You enter every number; the tool only does this arithmetic.Dose-volume formula — StatPearls "Dose Calculation" (Bookshelf NBK430836) ↗
An opened (punctured) multi-dose vial is dated and discarded within 28 days unless the manufacturer states otherwise.CDC Injection Safety (per USP General Chapter <797>) ↗

Educational calculator only — not medical advice and not a recommended dose. You enter your own numbers; we only do the arithmetic. Some products are not approved for human use; verify your product and dose with a licensed clinician.

Built by the makers of Glipath — the private GLP-1 companion for iPhone.