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

The whole 2.5 to 15 mg ladder, converted into the mark on your syringe. Works for 10, 20, 30 and 60 mg vials.

IndependentThis site does not sell peptides and is not owned by a vendor. Every other calculator on page one of Google belongs to a shop.

The maths is openThe formula is written out on this page and the code behind it is a single file with an automated test suite.

How it earnsAffiliate links on one clearly marked page, and nowhere else. Never inside the calculator.

ReviewedDose ranges and half-life figures last checked 3 September 2026.

Dose to units, at the standard setup

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

Based on a 30 mg vial reconstituted with 3 mL of bacteriostatic water, which is 10 mg/mL, drawn on a standard U-100 insulin syringe, once weekly.

About the numbers above

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.

A 30 mg vial at different water volumes

If the draw feels awkward to read, change the water rather than 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 stays in you

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.

Buying Tirzepatide? The where to buy page lists the vendors this site uses and what to check before ordering, and Peptide Bureau keeps the ranked vendor scorecard.

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