Enter your tirzepatide vial size and the volume of bacteriostatic water you are adding. The calculator returns the concentration in mcg/ml and the exact units to draw on a U-100 insulin syringe. It handles the common 10mg, 15mg, 30mg and 60mg vials at every titration step.
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Results
Concentration
15000 mcg/ml
15 mg/ml
Volume to inject
0.167 ml
per dose
Units on insulin syringe (U-100)
16.7 units
on a standard 100-unit insulin syringe
Doses per vial
12 doses
at 2500 mcg each
How this is calculated
30mg × 1,000 = 30000 mcg total
30000 ÷ 2ml = 15000 mcg/ml
2500 mcg ÷ 15000 = 0.1667 ml
0.1667 ml × 100 = 16.7 units
Disclaimer: This calculator is provided for informational purposes only. Always verify results against your specific vial labelling before use. Peptidy does not provide medical advice — consult a qualified healthcare professional before beginning or modifying any protocol. Use of research peptides may be subject to legal restrictions in your jurisdiction.
Tirzepatide is a dual GIP/GLP-1 receptor agonist dosed once weekly and titrated upward every four weeks. Vials are more concentrated than semaglutide — 30mg and 60mg are common — so getting the reconstitution right is important: the same 20-unit draw delivers very different amounts depending on how much water you added.
The titration schedule used in the SURMOUNT and SURPASS trials. Each step is held for at least four weeks; many people stay at 5mg, 7.5mg or 10mg rather than reaching the 15mg maximum.
| Weeks 1–4 (starting dose) | 2.5 mg (2,500 mcg) once weekly |
| Weeks 5–8 | 5 mg (5,000 mcg) once weekly |
| Weeks 9–12 | 7.5 mg (7,500 mcg) once weekly |
| Weeks 13–16 | 10 mg (10,000 mcg) once weekly |
| Weeks 17–20 | 12.5 mg (12,500 mcg) once weekly |
| Week 21 onward (max) | 15 mg (15,000 mcg) once weekly |
Worked example: 30mg vial + 2ml BAC water, 2.5mg starting dose
2ml is a common choice, giving 15,000 mcg/ml (15mg/ml). At that concentration a 2.5mg starting dose is about 16.7 units and a 5mg dose is about 33.3 units. Adding 1.5ml instead gives 20mg/ml, which lowers the injection volume if you are dosing at the higher end.
With a 30mg vial reconstituted in 2ml (15,000 mcg/ml): 2,500 ÷ 15,000 = 0.167ml = about 16.7 units. With a 30mg vial in 1.5ml (20,000 mcg/ml): 2,500 ÷ 20,000 = 0.125ml = 12.5 units. Enter your own numbers above for an exact figure.
Add your chosen volume of BAC water — 2ml gives a clean 15mg/ml. Draw 2.5mg by pulling to roughly 16.7 units on a U-100 insulin syringe. A single 30mg vial then provides 12 starting doses. When you titrate to 5mg you would draw double (about 33 units) and the vial would last 6 weeks.
It depends on your weekly dose. At 2.5mg a 30mg vial gives 12 doses; at 5mg it gives 6; at 10mg it gives 3; at 15mg it gives 2. The doses-per-vial figure above updates automatically when you change the dose.
No — tirzepatide vials are far more concentrated, so the same number of units delivers a very different amount. Always recalculate units from your specific vial size and BAC water volume rather than reusing a figure from a different compound.
Refrigerate at 2–8°C, protect it from light, and label the vial with the date you reconstituted it. Reconstituted tirzepatide in bacteriostatic water is commonly used within 4–8 weeks. Do not freeze it.
Store your vial concentration, log every dose against it, and never lose track of what you injected or when.