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Tirzepatide Calculator

A vial strength and a water volume give a concentration. A concentration and a syringe give units. Worked for the vial sizes tracked across vendors — not generic examples.

Last reviewed: September 20, 2026

Vial strength and water volume give a concentration; a dose then gives the unit mark it corresponds to.

Tirzepatide

Vial sizes vendors carry — tap to fill:

How much bac water?
Syringe barrel

For research purposes only. Always verify calculations independently before use.

On this page
  1. 1.What reconstitution is
  2. 2.What sizes does tirzepatide come in?
  3. 3.The arithmetic, worked
  4. 4.Units to draw, by vial size and dose
  5. 5.What one vial comes to
  6. 6.What changes the answer
  7. 7.How long does reconstituted tirzepatide last?
  8. 8.FAQ
  9. 9.References

What reconstitution is

Research-grade tirzepatide ships from vendors as a lyophilized (freeze-dried) powder sealed in a vial. Reconstitution is the act of dissolving that powder in a liquid — typically bacteriostatic water — which turns a fixed mass of peptide (the vial’s labeled mg content) into a solution with a defined concentration, measurable in volume with a syringe. The mass doesn’t change; only how that mass is distributed through a volume of liquid changes.

Tirzepatide itself is FDA-approved — as Mounjaro and Zepbound, both sold as pre-filled, ready-to-use solutions that the patient never reconstitutes. Neither label contains reconstitution instructions for that reason. The math below is generic pharmaceutical arithmetic (concentration = mass ÷ volume), applied to the vial sizes research-grade tirzepatide is actually sold in. For the compound’s mechanism (a dual GIP/GLP-1 receptor agonist) and trial evidence, see the tirzepatide profile.

What sizes does tirzepatide come in?

Read from live price data on September 20, 2026 (non-retired vendors only), 30 distinct vendors carry tirzepatide. The seven sizes below are each carried by 3 or more of those vendors. Coverage concentrates heavily at 10 mg, 30 mg, and 60 mg — each carried by 15 or more vendors — with 15 mg and 20 mg as a thinner middle tier.

Vial sizeVendors tracking this size
5 mg3
10 mg20
15 mg7
20 mg8
30 mg21
40 mg5
60 mg15

The arithmetic, worked

Concentration (mg/mL) equals the vial’s total mg divided by the water volume in mL. Micrograms per syringe unit, on a U-100 syringe (100 units = 1 mL), equals that concentration multiplied by 10. The table below reports both figures at two illustrative water volumes for each tracked size — as a statement of what each volume does to the concentration, not a recommendation of either:

Vial sizeAt 1 mL waterAt 2 mL water
5 mg5 mg/mL — 50 mcg/unit2.5 mg/mL — 25 mcg/unit
10 mg10 mg/mL — 100 mcg/unit5 mg/mL — 50 mcg/unit
15 mg15 mg/mL — 150 mcg/unit7.5 mg/mL — 75 mcg/unit
20 mg20 mg/mL — 200 mcg/unit10 mg/mL — 100 mcg/unit
30 mg30 mg/mL — 300 mcg/unit15 mg/mL — 150 mcg/unit
40 mg40 mg/mL — 400 mcg/unit20 mg/mL — 200 mcg/unit
60 mg60 mg/mL — 600 mcg/unit30 mg/mL — 300 mcg/unit

Doubling the water volume halves the concentration and halves the mcg delivered per unit drawn. The general dosage calculator runs this same arithmetic for any vial size and water volume, including ones outside the table above.

Units to draw, by vial size and dose

Every cell is the U-100 unit mark a given dose comes to, for a given vial strength, at 2 mL of bacteriostatic water. The rows are the vial sizes three or more tracked vendors carry; the columns are round dose values, chosen so the table reads cleanly across that range. They are not a schedule and nothing here suggests one — the label schedules for the branded tirzepatide products are set out in the Mounjaro and Zepbound dosing guides.

Vial1 mg2 mg5 mg7.5 mg10 mg15 mg20 mg
5 mg40.080.0200.0300.0400.0600.0800.0
10 mg20.040.0100.0150.0200.0300.0400.0
15 mg13.326.766.7100.0133.3200.0266.7
20 mg10.020.050.075.0100.0150.0200.0
30 mg6.713.333.350.066.7100.0133.3
40 mg5.010.025.037.550.075.0100.0
60 mg3.36.716.725.033.350.066.7

Figures over 100 are shown in amber: they exceed a 1 mL U-100 barrel at this water volume, so that combination does not fit one syringe. More water lowers the concentration and raises the unit count; less water does the reverse. The calculator above works any vial, volume and dose, in either direction.

What one vial comes to

The three sizes the most tracked vendors carry, worked at 2 mL. “Doses per vial” is the vial’s total divided by the dose — how many times that amount is present in the vial, before any loss in handling.

30 mg vial at 2 mL — 15.00 mg/mL

DoseUnits to drawDraw volumeDoses per vial
1 mg6.70.07 mL30.0
2 mg13.30.13 mL15.0
5 mg33.30.33 mL6.0
7.5 mg50.00.50 mL4.0
10 mg66.70.67 mL3.0
15 mg100.01.00 mL2.0
20 mg133.31.33 mL1.5

10 mg vial at 2 mL — 5.00 mg/mL

DoseUnits to drawDraw volumeDoses per vial
1 mg20.00.20 mL10.0
2 mg40.00.40 mL5.0
5 mg100.01.00 mL2.0
7.5 mg150.01.50 mL1.3
10 mg200.02.00 mL1.0
15 mg300.03.00 mL0.7
20 mg400.04.00 mL0.5

60 mg vial at 2 mL — 30.00 mg/mL

DoseUnits to drawDraw volumeDoses per vial
1 mg3.30.03 mL60.0
2 mg6.70.07 mL30.0
5 mg16.70.17 mL12.0
7.5 mg25.00.25 mL8.0
10 mg33.30.33 mL6.0
15 mg50.00.50 mL4.0
20 mg66.70.67 mL3.0

What changes the answer

  • Water volume. Concentration is inversely proportional to water volume. A larger water volume produces a lower concentration, meaning more units are needed to reach the same mg amount, which can exceed a syringe’s barrel capacity at low concentrations and high mg amounts — a real constraint at tirzepatide’s higher vial sizes (40 mg, 60 mg) more than at its smaller ones.
  • Vial size. For a fixed water volume, concentration is directly proportional to vial size — a 30 mg vial reconstituted with 1 mL is three times the concentration of a 10 mg vial reconstituted the same way.
  • Syringe calibration. Every figure above assumes a U-100 syringe (100 units = 1 mL), the standard for peptide research (see the syringes and injection guide). A different calibration would report a different units figure for the identical physical volume; it does not change the concentration or the mg delivered.

How long does reconstituted tirzepatide last?

Mounjaro and Zepbound’s labels state their pre-filled single-dose pens and vials are refrigerated at 2–8°C (36–46°F), and may be kept unrefrigerated at or below 30°C (86°F) for up to a total of 21 days before being discarded. That figure describes a manufactured, ready-to-use solution — not a research-grade lyophilized vial before or after a buyer reconstitutes it with bacteriostatic water.

Prof. Peptide has not identified a sourced figure for how long reconstituted research-grade tirzepatide remains stable, refrigerated or otherwise, from any manufacturer, regulator, or published study. This page does not state one as fact. A vendor’s own product page may state a shelf-life figure; that is the vendor’s claim, not an independently verified one, and is outside what this page reports.

FAQ

How do I reconstitute tirzepatide?
Reconstitution is dissolving the lyophilized (freeze-dried) powder in a liquid, typically bacteriostatic water, to create a measurable solution. This page reports the resulting concentration math for the vial sizes tracked here; it does not state a water volume to use, since that is a choice, not arithmetic.
Does the water volume change how much tirzepatide is in the vial?
No. A 30 mg vial contains 30 mg of tirzepatide regardless of the water volume added. What changes is the concentration — milligrams per milliliter — and therefore how many syringe units correspond to a given milligram amount.
What syringe do the unit figures on this page assume?
A U-100 insulin syringe, where 100 units equals 1 mL. See the syringes and injection guide for barrel sizes and needle gauge.
Is this the same as how Mounjaro or Zepbound are dosed?
No. Mounjaro and Zepbound are FDA-approved, pre-filled, ready-to-use pen or vial products — the patient never reconstitutes them. This page's arithmetic applies to research-grade lyophilized tirzepatide, which a buyer reconstitutes themselves. See the Mounjaro and Zepbound dosing guides for the branded labels' own escalation schedules.
What if my vial's size isn't in the table below?
The table covers sizes carried by 3 or more tracked vendors. Any size can be worked the same way: concentration (mg/mL) equals the vial's total mg divided by the water volume in mL, and mcg per syringe unit equals that concentration times 10 (on a U-100 syringe). The general dosage calculator performs this for any size.
How much BAC water for a 5mg tirzepatide vial?
A 5 mg vial holds 5 mg of tirzepatide whatever volume of bacteriostatic water is added — the water sets the concentration, not the amount in the vial. At 1 mL that vial reads 5 mg/mL, so one unit on a U-100 syringe carries 50 mcg. At 2 mL it reads 2.50 mg/mL and one unit carries 25 mcg. At 3 mL it reads 1.67 mg/mL and one unit carries 16.7 mcg. Which of those volumes to add is a choice this page does not make; the calculator above works any combination, in either direction.
How much BAC water for a 10mg tirzepatide vial?
A 10 mg vial holds 10 mg of tirzepatide whatever volume of bacteriostatic water is added — the water sets the concentration, not the amount in the vial. At 1 mL that vial reads 10 mg/mL, so one unit on a U-100 syringe carries 100 mcg. At 2 mL it reads 5.00 mg/mL and one unit carries 50 mcg. At 3 mL it reads 3.33 mg/mL and one unit carries 33.3 mcg. Which of those volumes to add is a choice this page does not make; the calculator above works any combination, in either direction.
How much BAC water for a 15mg tirzepatide vial?
A 15 mg vial holds 15 mg of tirzepatide whatever volume of bacteriostatic water is added — the water sets the concentration, not the amount in the vial. At 1 mL that vial reads 15 mg/mL, so one unit on a U-100 syringe carries 150 mcg. At 2 mL it reads 7.50 mg/mL and one unit carries 75 mcg. At 3 mL it reads 5.00 mg/mL and one unit carries 50.0 mcg. Which of those volumes to add is a choice this page does not make; the calculator above works any combination, in either direction.
How much BAC water for a 20mg tirzepatide vial?
A 20 mg vial holds 20 mg of tirzepatide whatever volume of bacteriostatic water is added — the water sets the concentration, not the amount in the vial. At 1 mL that vial reads 20 mg/mL, so one unit on a U-100 syringe carries 200 mcg. At 2 mL it reads 10.00 mg/mL and one unit carries 100 mcg. At 3 mL it reads 6.67 mg/mL and one unit carries 66.7 mcg. Which of those volumes to add is a choice this page does not make; the calculator above works any combination, in either direction.
How much BAC water for a 30mg tirzepatide vial?
A 30 mg vial holds 30 mg of tirzepatide whatever volume of bacteriostatic water is added — the water sets the concentration, not the amount in the vial. At 1 mL that vial reads 30 mg/mL, so one unit on a U-100 syringe carries 300 mcg. At 2 mL it reads 15.00 mg/mL and one unit carries 150 mcg. At 3 mL it reads 10.00 mg/mL and one unit carries 100.0 mcg. Which of those volumes to add is a choice this page does not make; the calculator above works any combination, in either direction.
How much BAC water for a 40mg tirzepatide vial?
A 40 mg vial holds 40 mg of tirzepatide whatever volume of bacteriostatic water is added — the water sets the concentration, not the amount in the vial. At 1 mL that vial reads 40 mg/mL, so one unit on a U-100 syringe carries 400 mcg. At 2 mL it reads 20.00 mg/mL and one unit carries 200 mcg. At 3 mL it reads 13.33 mg/mL and one unit carries 133.3 mcg. Which of those volumes to add is a choice this page does not make; the calculator above works any combination, in either direction.
How much BAC water for a 50mg tirzepatide vial?
A 50 mg vial holds 50 mg of tirzepatide whatever volume of bacteriostatic water is added — the water sets the concentration, not the amount in the vial. At 1 mL that vial reads 50 mg/mL, so one unit on a U-100 syringe carries 500 mcg. At 2 mL it reads 25.00 mg/mL and one unit carries 250 mcg. At 3 mL it reads 16.67 mg/mL and one unit carries 166.7 mcg. Which of those volumes to add is a choice this page does not make; the calculator above works any combination, in either direction.
How much BAC water for a 60mg tirzepatide vial?
A 60 mg vial holds 60 mg of tirzepatide whatever volume of bacteriostatic water is added — the water sets the concentration, not the amount in the vial. At 1 mL that vial reads 60 mg/mL, so one unit on a U-100 syringe carries 600 mcg. At 2 mL it reads 30.00 mg/mL and one unit carries 300 mcg. At 3 mL it reads 20.00 mg/mL and one unit carries 200.0 mcg. Which of those volumes to add is a choice this page does not make; the calculator above works any combination, in either direction.
How much BAC water for a 100mg tirzepatide vial?
A 100 mg vial holds 100 mg of tirzepatide whatever volume of bacteriostatic water is added — the water sets the concentration, not the amount in the vial. At 1 mL that vial reads 100 mg/mL, so one unit on a U-100 syringe carries 1000 mcg. At 2 mL it reads 50.00 mg/mL and one unit carries 500 mcg. At 3 mL it reads 33.33 mg/mL and one unit carries 333.3 mcg. Which of those volumes to add is a choice this page does not make; the calculator above works any combination, in either direction.
How much BAC water for a 120mg tirzepatide vial?
A 120 mg vial holds 120 mg of tirzepatide whatever volume of bacteriostatic water is added — the water sets the concentration, not the amount in the vial. At 1 mL that vial reads 120 mg/mL, so one unit on a U-100 syringe carries 1200 mcg. At 2 mL it reads 60.00 mg/mL and one unit carries 600 mcg. At 3 mL it reads 40.00 mg/mL and one unit carries 400.0 mcg. Which of those volumes to add is a choice this page does not make; the calculator above works any combination, in either direction.

References

  1. Eli Lilly and Company. MOUNJARO (tirzepatide) injection — prescribing information, section 16 (How Supplied/Storage and Handling). DailyMed, setid d2d7da5d-ad07-4228-955f-cf7e355c8cc0, effective 2026-08-27. https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=d2d7da5d-ad07-4228-955f-cf7e355c8cc0
  2. Eli Lilly and Company. ZEPBOUND (tirzepatide) injection — prescribing information, section 16 (How Supplied/Storage and Handling). DailyMed, setid 487cd7e7-434c-4925-99fa-aa80b1cc776b, effective 2026-08-28. https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=487cd7e7-434c-4925-99fa-aa80b1cc776b

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