Tirzepatide Reconstitution Calculator

Compounded tirzepatide — which is not FDA-approved and may be illegal to obtain without a prescription — comes as powder in a wide range of vial sizes, and the same 5 mg dose can be anywhere from 10 to 100 units depending on the mix. This page converts a dose you already have into an exact draw; it does not recommend one.

This is a unit converter. It converts an amount you already have into volume and syringe units. It does not tell you what to take, and it is educational only — not medical advice. Confirm every amount with your clinician and your product label.

Example mixes to try the converter

Examples only — not recommended amounts. These fill in a vial size and diluent volume only — never an amount to inject. Enter the dose your clinician gave you yourself.

Vial size (mg)

Total compound in the vial.

BAC water added (mL)

Volume of bacteriostatic water you reconstitute with.

Target dose

Enter your target dose as a number.

Syringe type

U-100 = 100 units per mL (standard). U-40 = 40 units per mL.

Nothing calculated yet

Enter your target dose as a number.

Tirzepatide concentration reference (mg/mL)

What each vial size becomes at common bacteriostatic water volumes.

Vial	+ 1 mL	+ 2 mL	+ 3 mL	+ 5 mL
10 mg	10.00 mg/mL	5.00 mg/mL	3.33 mg/mL	2.00 mg/mL
15 mg	15.00 mg/mL	7.50 mg/mL	5.00 mg/mL	3.00 mg/mL
20 mg	20.00 mg/mL	10.00 mg/mL	6.67 mg/mL	4.00 mg/mL
30 mg	30.00 mg/mL	15.00 mg/mL	10.00 mg/mL	6.00 mg/mL
40 mg	40.00 mg/mL	20.00 mg/mL	13.33 mg/mL	8.00 mg/mL
60 mg	60.00 mg/mL	30.00 mg/mL	20.00 mg/mL	12.00 mg/mL

Tirzepatide doses reported in research

The figures below are doses reported in published clinical trials or, where no human trials exist, ranges reported anecdotally. They are reference data only. DoseRoutine does not recommend doses — your prescriber decides yours.

Phase	Dose	Frequency	Notes
Weeks 1–4	2.5 mg	Once weekly	Starting dose — not intended for weight loss on its own.
Weeks 5–8	5 mg	Once weekly	First maintenance dose.
Weeks 9+	7.5–15 mg	Once weekly	The labeled schedule escalates in 2.5 mg steps, at least 4 weeks apart.
Maximum	15 mg	Once weekly	Highest labeled dose for Mounjaro and Zepbound.

Reference ranges reported in the literature and in common practice — not a prescription, and not personalized advice.

What trips people up

Mixing 1 mL of BAC water per 10 mg of tirzepatide gives a tidy 10 mg/mL: 2.5 mg = 25 units, 5 mg = 50 units.
Branded pens (Mounjaro, Zepbound) come pre-filled — this calculator is for compounded or research powder vials only.
The labeled schedule escalates no faster than every 4 weeks — most severe GI side effects in trials came from rushed titration. Compounded or research-grade tirzepatide is not FDA-approved, and obtaining it without a prescription may be illegal.
Tirzepatide is a GLP-1/GIP dual agonist and slows gastric emptying, which can change how quickly oral medications are absorbed.

How the math works

Concentration (mg/mL) = vial mg ÷ bacteriostatic water mL.
Volume per dose (mL) = dose mg ÷ concentration.
Syringe units = volume × 100 on a U-100 syringe, or × 40 on a U-40 syringe.
Doses per vial = vial mg ÷ dose mg. Water volume never changes this number.

Tirzepatide calculator FAQ

How much BAC water do I add to a 30 mg tirzepatide vial?

3 mL is the most common choice, giving 10 mg/mL. On that concentration a 2.5 mg dose is 25 units, 5 mg is 50 units, 7.5 mg is 75 units and 10 mg is 100 units — a full U-100 syringe.

How many units is 5 mg of tirzepatide?

At 10 mg/mL it is 0.5 mL = 50 units on a U-100 syringe. At 20 mg/mL (30 mg + 1.5 mL) the same dose is 25 units. Concentration is the only thing that decides this.

How long does reconstituted tirzepatide last?

Refrigerated and mixed with bacteriostatic water, it is generally treated as usable for around 28–30 days. Keep it cold, keep it out of light, and swab the stopper before every draw.

What's the difference between tirzepatide and semaglutide dosing?

They are not interchangeable. Tirzepatide runs 2.5–15 mg weekly; semaglutide runs 0.25–2.4 mg weekly. Do not convert one to the other by ratio — switch under clinical supervision.

Tirzepatide reference page Check interactions Semaglutide vs tirzepatide

Educational tool only — not medical advice. Verify every dose with your prescriber and follow sterile technique. See our medical disclaimer.

More free DoseRoutine calculators and dosing references.

Reviewed by the DoseRoutine editorial team. Last reviewed 2026-08-03.

Who maintains this page

The DoseRoutine Editorial Team maintains the compound library and the interaction rule set behind DoseRoutine. We summarize published trials, regulatory documents (FDA, EMA) and company announcements into plain-English updates. Every factual claim on a post is tied to a linked source below.

Posts are written and reviewed by the editorial team, not by a licensed clinician. This is educational reference content — it never recommends an amount for you to take.

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