Compounded Tirzepatide Dose Calculator and Dosage Chart

Enter the strength printed on your vial and your prescribed dose to see how many milliliters to draw and the matching mark on a U-100 insulin syringe. You can also turn a syringe reading back into milligrams. The dose steps come from the Zepbound and Mounjaro prescribing information.

1. Vial strength on your pharmacy label

Label shows mg per mLLabel shows total mg and total mL

Concentration

Printed on the vial or pharmacy label, for example 10 mg/mL.

2. What do you want to work out?

Units to draw for a dose in mgThe dose in a number of units

Prescribed weekly dose

Enter the vial strength from your pharmacy label to start.

The calculator runs in your browser and does not send or save what you enter.

Your printable dose chart

Enter your vial strength above to fill in the volume and units for each dose step.

Dose steps and earliest weeks follow the Zepbound and Mounjaro labels: each increase comes after at least 4 weeks on the current dose. Your prescriber decides whether and when your dose changes.

Tirzepatide dosage chart

The Zepbound and Mounjaro labels start at 2.5 mg once a week for 4 weeks. After that, the dose can go up in 2.5 mg steps, each after at least 4 weeks on the current dose, to a maximum of 15 mg a week.

Source: Zepbound and Mounjaro prescribing information, section 2.
Earliest weeks	Weekly dose	What the label says
1–4	2.5 mg	Starting dose. Not a maintenance dose.
5–8	5 mg	First increase. A Zepbound maintenance dose.
9–12	7.5 mg	Step toward 10 mg.
13–16	10 mg	A Zepbound maintenance dose, including for sleep apnea.
17–20	12.5 mg	Step toward 15 mg.
21+	15 mg	Maximum weekly dose. A Zepbound maintenance dose, including for sleep apnea.

The weeks are the earliest the label allows, not a deadline. The Zepbound label tells prescribers to weigh response and tolerability when choosing a maintenance dose and to consider a lower one if a dose isn’t tolerated. On Mounjaro, which treats type 2 diabetes, the dose goes up only if more blood sugar control is needed, and the maximum for children 10 and older is 10 mg.

These labels were written for Zepbound and Mounjaro. Compounded tirzepatide is not FDA-approved, and FDA does not review compounded drugs for safety, effectiveness, or quality before they are marketed. Your prescription sets your dose.

How to convert tirzepatide mg to units

Divide the dose by the vial’s concentration to get milliliters. Then multiply by 100 to get units on a U-100 insulin syringe, where each unit mark is 0.01 mL.

mL = dose (mg) ÷ concentration (mg/mL)
units = mL × 100

2.5 mg from a 10 mg/mL vial: 2.5 ÷ 10 = 0.25 mL, which is 25 units.
5 mg from a 20 mg/mL vial: 5 ÷ 20 = 0.25 mL, also 25 units.
7.5 mg from a 25 mg/mL vial: 7.5 ÷ 25 = 0.3 mL, which is 30 units.

The first two examples draw the same 25 units but deliver different doses. Units measure volume, not drug, so a unit count only means something alongside the vial’s concentration.

If your label gives the total contents instead, such as 20 mg/2 mL, divide first: 20 ÷ 2 = 10 mg/mL. To go the other way, divide the units by 100 and multiply by the concentration: 40 units from a 20 mg/mL vial is 0.4 mL × 20 = 8 mg.

Units for each dose at example concentrations

U-100 syringe units. These concentrations are examples; use the one on your label.

U-100 syringe units for each tirzepatide dose at example concentrations
Dose	10 mg/mL	15 mg/mL	20 mg/mL	25 mg/mL	30 mg/mL
2.5 mg	25	16.7	12.5	10	8.3
5 mg	50	33.3	25	20	16.7
7.5 mg	75	50	37.5	30	25
10 mg	100	66.7	50	40	33.3
12.5 mg	125*	83.3	62.5	50	41.7
15 mg	150*	100	75	60	50

* More than a full 1 mL syringe.

Why unit doses go wrong

In 2024 FDA warned about overdoses with compounded semaglutide, most from multiple-dose vials. Some patients drew 5 to 20 times their intended dose, and some clinicians miscalculated when converting milligrams to units or milliliters. In several cases a patient told to draw 5 units (0.05 mL) on a U-100 syringe drew 50 units. The same arithmetic applies to tirzepatide vials.

If your pharmacy changes your vial’s concentration, your units change even when your dose doesn’t. Recalculate with every new vial.
The unit numbers here match U-100 insulin syringes only.
Use the syringe your pharmacy or prescriber provides. FDA asks compounders and prescribers to supply a syringe sized for the dose.

How branded pens and vials compare

Zepbound and Mounjaro single-dose pens and vials hold one dose in 0.5 mL, whatever the strength. Their multi-dose vials and KwikPens hold four 0.6 mL doses, so the concentration rises with the dose, from 4.17 mg/mL for 2.5 mg to 25 mg/mL for 15 mg. For vials, the labels call for a syringe that can measure a 0.5 mL or 0.6 mL dose.

Compounded multiple-dose vials don’t follow that pattern. The pharmacy sets the concentration, and FDA notes that compounded concentrations can differ, so the volume and units for the same dose vary from one vial to another.

Common questions

How many units is 2.5 mg or 5 mg of tirzepatide?

It depends on your vial’s concentration. On a U-100 syringe, 2.5 mg is 25 units from a 10 mg/mL vial, 12.5 units from 20 mg/mL, and 8.3 units from 30 mg/mL. 5 mg is 50, 25, and 16.7 units at those strengths. Enter the concentration on your label in the calculator to get your number.

How many doses are in a tirzepatide vial?

Divide the total milligrams in the vial by your dose. A vial with 20 mg in total holds eight 2.5 mg doses or four 5 mg doses. Don’t use the vial after the beyond-use date on the pharmacy label, even if some is left.

What if I miss a weekly dose?

The Zepbound and Mounjaro labels say to take a missed dose as soon as possible within 4 days (96 hours). If more than 4 days have passed, skip it and take the next dose on your usual day. You can change your injection day as long as doses are at least 3 days (72 hours) apart.

Can the dose go up faster than every 4 weeks?

The labels call for at least 4 weeks on each dose before a 2.5 mg increase, a schedule meant to reduce stomach and bowel side effects. Dose changes are your prescriber’s decision.

Is compounded tirzepatide the same as Zepbound or Mounjaro?

No. Zepbound and Mounjaro are FDA-approved products. Compounded tirzepatide is made by a pharmacy for an individual prescription, is not FDA-approved, and its concentration and dose volume are set by that pharmacy.

Which syringe should I use?

Use the syringe your pharmacy or prescriber supplies. This calculator assumes a U-100 insulin syringe, where 100 units equal 1 mL. Common sizes hold 30 units (0.3 mL), 50 units (0.5 mL), or 100 units (1 mL), and the calculator shows the smallest of these that holds your dose.

References

Updated October 16, 2026. Dosing details checked against the Zepbound and Mounjaro labels on DailyMed (versions effective August 28 and August 27, 2026).