Read the strength on every vial
A new vial can be stronger or weaker than the last. Work out your units again whenever the label changes.
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Tirzepatide dosage calculator
See how many units of tirzepatide to draw for your dose. Made for compounded tirzepatide vials: enter the strength from your label and your dose in mg, and get the units on a U-100 insulin syringe.
Taking semaglutide? Use the semaglutide dosage calculator
Draw up to
25units on a U-100 syringe
- Liquid
- 0.25 mL
- Dose
- 2.5 mg
- Strength
- 10 mg/mL
A conversion, not medical advice. Use the dose your prescriber gave you, check the strength on every new vial, and confirm your first draw with your pharmacist.
The short answer
How to convert tirzepatide mg to units
Divide your dose in mg by the vial strength in mg per mL, then multiply by 100. With a 10 mg/mL vial, a 2.5 mg dose of tirzepatide is 0.25 mL, which is 25 units on a U-100 syringe. The strength on your label decides the answer, so the same dose can be a different number of units from one vial to the next.
To go the other way, from units to mg, divide the units by 100 and multiply by the vial strength: 25 units of a 10 mg/mL vial is 2.5 mg.
Dosage chart
Compounded tirzepatide dosage chart in units
Units to draw on a U-100 insulin syringe for each approved weekly dose of tirzepatide, from 2.5 mg to 15 mg, at three common vial strengths. Find your dose in the left column and the strength from your label along the top.
| Dose | 5 mg/mL vial | 10 mg/mL vial | 20 mg/mL vial |
|---|---|---|---|
| 2.5 mg | 50 units (0.5 mL) | 25 units (0.25 mL) | 12.5 units (0.125 mL) |
| 5 mg | 100 units (1 mL) | 50 units (0.5 mL) | 25 units (0.25 mL) |
| 7.5 mg | 150 units (1.5 mL) | 75 units (0.75 mL) | 37.5 units (0.375 mL) |
| 10 mg | 200 units (2 mL) | 100 units (1 mL) | 50 units (0.5 mL) |
| 12.5 mg | 250 units (2.5 mL) | 125 units (1.25 mL) | 62.5 units (0.625 mL) |
| 15 mg | 300 units (3 mL) | 150 units (1.5 mL) | 75 units (0.75 mL) |
The doses are the approved weekly strengths, listed only to show the conversion. Follow the dose and the schedule your prescriber gave you. If your vial has a different strength, use the calculator above.
Before you draw
Four checks that prevent a wrong dose
The FDA has reported overdoses with compounded semaglutide, many from mixing up mg, mL and units.
mg, mL and units are different
mg is the medicine, mL is the liquid, units are lines on the syringe. Your prescription is in mg.
Use a U-100 syringe
The units here are for U-100 insulin syringes, where 100 units are 1 mL. Pick a size that holds your whole dose.
Check your first draw
Ask your pharmacist or prescriber to confirm the units the first time, and after any change of dose or vial.
On a GLP-1
Eat enough protein while the weight comes off
With less appetite it is easy to eat too little protein and lose muscle along with fat. The protein calculator sets a daily target that accounts for GLP-1 use, and Protein Buddy helps you hit it in small meals. Taking semaglutide? Use the semaglutide dosage calculator.
Check our sources
Research and guidance
- FDA alert on dosing errors with compounded semaglutideOverdoses from mixing up mg, mL and units, and how to avoid them.
- FDA concerns with unapproved GLP-1 drugsWhat to know about compounded GLP-1 medication.
- GLP-1 nutrition advisoryProtein and nutrition during GLP-1 treatment.
Frequently asked questions
- How many units of tirzepatide is 2.5 mg?
- 25 units with a 10 mg/mL vial. The answer depends on the strength of your vial: 2.5 mg is 12.5 units at 20 mg/mL and 50 units at 5 mg/mL, always on a U-100 insulin syringe.
- How many units of tirzepatide is 5 mg?
- 50 units with a 10 mg/mL vial (0.5 mL). At 20 mg/mL it is 25 units. Check the strength on your label and use the calculator above for your exact vial.
- How do I convert tirzepatide mg to units?
- Divide your dose in mg by the vial strength in mg per mL to get mL, then multiply by 100, because on a U-100 syringe 100 units are 1 mL. For example 2.5 mg ÷ 10 mg/mL = 0.25 mL = 25 units.
- How do I convert tirzepatide units to mg?
- Divide the units by 100 to get mL, then multiply by the vial strength in mg per mL. For example 25 units from a 10 mg/mL vial is 0.25 mL × 10 = 2.5 mg.
- What size syringe should I use for tirzepatide?
- One that holds your whole dose in a single draw. A 0.3 mL (30 unit) syringe has the finest scale and suits small doses, a 0.5 mL (50 unit) syringe suits most doses, and a 1 mL (100 unit) syringe holds the most but its lines are usually 2 units apart. Ask your pharmacist which one matches your dose.
- What does a unit mean on an insulin syringe?
- A unit on a U-100 insulin syringe is a measure of liquid, not of medicine: 1 unit is 0.01 mL. How much medicine those units hold depends on how strong the liquid in your vial is, which is why the same dose can be a different number of units with a different vial.
- Why did my units change with a new vial?
- Compounded vials come in different strengths, and a pharmacy can change the strength from one order to the next. A stronger vial needs fewer units for the same mg. Check the strength on every new label and work out your units again before you draw.
- Do I need this calculator if I use a pen?
- Usually not. A prefilled pen gives a set dose, so there is nothing to convert. You need the calculation when your medication comes in a multi-dose vial that you draw up with a syringe, which is how most compounded medication is supplied.
- Can I use this calculator for Zepbound vials?
- There is nothing to convert. Zepbound vials from Lilly are single-dose: draw the whole vial as your instructions say and discard what is left. Lilly does not support keeping the leftover for another dose, because drawing from a single-dose vial again raises the risk of contamination. This calculator is for multi-dose compounded tirzepatide vials.
- Is this calculator medical advice?
- No. It only converts the dose you were prescribed into units for your syringe. Your prescriber decides the dose and when to change it, and your pharmacist can check your first draw with you.