How many units is 2.5 mg of Tirzepatide?

It depends entirely on how much water you added. In a 30 mg vial reconstituted with 3 mL, the concentration is 10 mg/mL, so 2.5 mg is 0.25 mL, which is 25 units on a U-100 insulin syringe. In the same vial with 1.5 mL of water it is 12.5 units, and with 4.5 mL it is 37.5 units.

How much bacteriostatic water for a 30 mg Tirzepatide vial?

3 mL is the usual choice. It gives 10 mg/mL, which puts the commonly reported range of 1 mg to 15 mg between roughly 10 and 150 units. Aim for a draw between about 10 and 50 units, where the barrel is easiest to read, and add or remove water to get there.

How many doses are in a 30 mg vial?

Divide 30 by your dose. At 2.5 mg that is 12 doses, which at once weekly is 84 days.

Is compounded tirzepatide the same as the licensed product?

No. Concentration, excipients and quality control differ. Anything you reconstitute yourself is at a concentration you chose, so unit counts from a pen do not transfer.

Tirzepatide dosage calculator

In a 30 mg vial with 3 mL of water (10 mg/mL), 2.5 mg of Tirzepatide is 25 units on a U-100 insulin syringe. The whole 2.5 to 15 mg ladder, converted into the mark on your syringe. Works for 10, 20, 30 and 60 mg vials.

Reviewed 3 September 2026
27 compounds
Formula on every page
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Peptulator, peptulator.com. Research use only, not medical advice.

Free downloadThe Protocol Pack

25 printable pages: dosing cards for the twelve most-used compounds at three water volumes, titration planners, a vial log, and five pages on what to do when it has already gone wrong.

Dose to units at the usual vial and water

Dose	U-100 units	Draw	Doses per vial	Vial lasts
2.5 mg	25 units	0.25 mL	12	84 days
5 mg	50 units	0.5 mL	6	42 days
7.5 mg	75 units	0.75 mL	4	28 days
10 mg	100 units	1 mL	3	21 days
12.5 mg	125 units	1.25 mL	2	14 days
15 mg	150 units	1.5 mL	2	14 days

30 mg vial in 3 mL of bacteriostatic water (10 mg/mL), U-100 insulin syringe, once weekly.

About Tirzepatide

Tirzepatide is a dual GIP and GLP-1 receptor agonist. The licensed titration ladder steps every four weeks: 2.5, 5, 7.5, 10, 12.5 and 15 mg once weekly, with 2.5 mg treated as a starting dose rather than a maintenance one.

Note that the licensed product is a pre-filled pen at a fixed concentration. Reconstituting a vial yourself means you set the concentration, so the unit numbers below will not match anything printed on a pen.

The same 30 mg vial at other water volumes

If the draw is awkward to read, change the water, not the dose. The dose stays the same; only the mark moves.

Vial	BAC water	Concentration	Draw	U-100 units	Doses/vial
30 mg	2 mL	15 mg/mL	0.167 mL	16.7 units	12
30 mg	3 mL	10 mg/mL	0.25 mL	25 units	12
30 mg	5 mL	6 mg/mL	0.417 mL	41.7 units	12
60 mg	2 mL	30 mg/mL	0.083 mL	8.3 units	24
60 mg	3 mL	20 mg/mL	0.125 mL	12.5 units	24
60 mg	5 mL	12 mg/mL	0.208 mL	20.8 units	24

All rows above assume a 2.5 mg dose and a standard U-100 insulin syringe, where 100 units = 1 mL.

How long it lasts in the body

The half-life of Tirzepatide is about 5 days. That is the time for the amount in your blood to halve, so after one half-life you are at 50 percent of the peak, after two you are at 25 percent, and after four you are at roughly 6 percent. This is why a weekly compound still has meaningful levels present when the next dose lands, and why levels build over the first several weeks before they settle.

Common questions

How many units is 2.5 mg of Tirzepatide?: It depends entirely on how much water you added. In a 30 mg vial reconstituted with 3 mL, the concentration is 10 mg/mL, so 2.5 mg is 0.25 mL, which is 25 units on a U-100 insulin syringe. In the same vial with 1.5 mL of water it is 12.5 units, and with 4.5 mL it is 37.5 units.
How much bacteriostatic water for a 30 mg Tirzepatide vial?: 3 mL is the usual choice. It gives 10 mg/mL, which puts the commonly reported range of 1 mg to 15 mg between roughly 10 and 150 units. Aim for a draw between about 10 and 50 units, where the barrel is easiest to read, and add or remove water to get there.
How many doses are in a 30 mg vial?: Divide 30 by your dose. At 2.5 mg that is 12 doses, which at once weekly is 84 days.
Is compounded tirzepatide the same as the licensed product?: No. Concentration, excipients and quality control differ. Anything you reconstitute yourself is at a concentration you chose, so unit counts from a pen do not transfer.

IndependentThis site does not sell peptides and is not owned by a vendor.

The maths is openThe formula is on every page and in the methodology. The code is one file with an automated test suite, run before each deploy.

How it is fundedNo ads and no vendor links here. It is published by the team behind Peptide Bureau, which earns from affiliate links on its own site, and VialHaus, the same team's vial storage shop, which the storage notes link to.

ReviewedDose ranges and half-lives checked 3 September 2026.

Buying Tirzepatide?

Peptulator does not list, rank or link vendors. Whoever the supplier is, use the strength printed on your own vial and check the batch certificate of analysis before you rely on any number here.

The Tirzepatide guideDosing, evidence and side effects, at Peptide Bureau Read a syringeU-100 vs U-40, and the 2.5x error Build a full protocolThe stack builder at Peptide Bureau, about two minutes

Common conversions

The same three-step maths, pre-filled for the doses people ask about most. Units on a U-100 insulin syringe, where 100 units is 1 mL.

mg to units calculator Any dose at any concentration, both directions, with the full reference tables
Units to mg calculator What the units you drew are in milligrams
1 mg to units The most-asked conversion, at every common setup
2 mg to units Retatrutide starting dose
2.5 mg to units Tirzepatide starting dose
5 mg to units Tirzepatide step two, MOTS-c, epitalon
10 mg to units Tirzepatide step four
12 mg to units Retatrutide top dose, tirzepatide 12.5 mg
15 mg to units Tirzepatide top dose

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MOTS-c calculator 5 to 10 mg, two or three times a week

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Dosage charts and schedules

Peptide reconstitution chart Concentration for every vial and water combination
Peptide dosing chart Printable unit tables for every compound
Retatrutide titration schedule 2 to 12 mg in units, stage by stage
Tirzepatide titration schedule 2.5 to 15 mg in units, stage by stage
Semaglutide titration schedule 0.25 to 2.4 mg in units, stage by stage
KLOW dosage and frequency chart The 80 mg blend at 2, 3 and 4 mL, both phases
GLOW dosage chart The 70 mg blend, units to each peptide
Wolverine stack dosing chart BPC-157 + TB-500, blend and separate vials
MOTS-c dosage chart 5 and 10 mg vials at three water volumes
Tirzepatide reconstitution chart Every vial size, every water volume, the whole ladder
Retatrutide dosing chart 1 to 12 mg across 10, 20 and 30 mg vials
Tirzepatide units to mg chart Both directions, every vial and water volume
Semaglutide units to mg chart The dosage chart in units, both directions
NAD+ injection dosage chart Per day, per week and frequency, 100 to 1,000 mg vials
Tesamorelin dosage chart 2, 5 and 10 mg vials, 0.5 to 2 mg in units
BPC-157 dosage chart mcg doses from 5 and 10 mg vials, four water volumes
PT-141 dosage chart The 10 mg vial, 0.5 to 2 mg, with uses per vial
Sermorelin dosage chart Nightly mcg doses from 5, 10 and 15 mg vials
Printable dosing charts Four one-page charts to save, pin or print
Peptide storage chart How long powder and mixed vials last, fridge to freezer

Tools

Peptide calculator The general tool, any compound
Reconstitution calculator How much water to add, and why it matters
Bacteriostatic water calculator Pick a volume that lands where you can read it
How to read an insulin syringe U-100 vs U-40, and the 2.5x error
The Protocol Pack Free 25-page printable reference
mg to units calculator Both directions, any concentration, with the reference tables
1 mg to units on an insulin syringe The conversion table for every common concentration
Units to mg calculator The mark you drew, back into milligrams
2 mg to units on an insulin syringe 2 mg at every common vial and water volume
2.5 mg to units on an insulin syringe 2.5 mg at every common vial and water volume
5 mg to units on an insulin syringe 5 mg at every common vial and water volume
10 mg to units on an insulin syringe 10 mg at every common vial and water volume
12 mg to units on an insulin syringe 12 mg at every common vial and water volume
15 mg to units on an insulin syringe 15 mg at every common vial and water volume
Methodology Every formula, assumption and rounding rule
About Peptulator Who publishes it, independence and contact
Embed the calculator One line of HTML, free, credit line only

Before you use these numbers This is a unit-conversion tool. It turns a vial strength and a water volume into a concentration, a draw volume and a syringe mark. It does not tell you what to take, whether to take it, or whether a compound is safe for you. Most compounds listed are sold for laboratory research and are not approved for human use. Nothing here is medical advice. Dosing decisions belong with a licensed clinician who knows your history. Always check the strength printed on your own vial rather than trusting a preset.