Understanding Tirzepatide Dosage: How Many Units Is 2.5 mg of Tirzepatide?

Last updated: July 16, 2025

Tirzepatide is prescribed weekly in milligrams (mg), but if you're using a compounded version delivered in a vial, your syringe will measure the medication in “units” of liquid. Understanding how to accurately convert mg into units based on the concentration of your vial is crucial for safe and effective dosing.

Why Units vs. Milligrams Matter

• Milligrams (mg) measure drug weight (the actual amount of tirzepatide).
• Units measure liquid volume—typically in insulin syringes, where 100 units = 1 mL.
• Most compounded tirzepatide comes in either 10 mg/mL or 20 mg/mL concentrations.

You must always know the concentration of your vial to convert milligrams into units correctly.

Conversion Table: Tirzepatide mg ➝ mL ➝ Syringe Units

Tirzepatide Dose (mg)Volume @10 mg/mLUnits (100 units = 1 mL)2.5 mg0.25 mL25 units5 mg0.50 mL50 units7.5 mg0.75 mL75 units10 mg1.00 mL100 units

Important:
If your vial is 20 mg/mL, then 2.5 mg equals 0.125 mL, or 12.5 units.

Standard Weekly Dosing Schedule

Week RangeDose (mg)Units (10 mg/mL vial)1–42.5 mg25 units5–85 mg50 units9–127.5 mg75 units13+10–15 mg100–150 units

This titration schedule allows your body to adjust and minimizes side effects like nausea and gastrointestinal discomfort.

Dosing Example: How Many Units Is 2.5 mg?

Let’s say your vial concentration is 10 mg/mL.
To find how many units you need for a 2.5 mg dose:

1. Divide 2.5 mg by 10 mg/mL = 0.25 mL
2. Multiply 0.25 mL by 100 = 25 units

So, 2.5 mg = 25 units on your syringe.

If your vial is 20 mg/mL, you would draw 12.5 units instead.

Step-by-Step Dosing Checklist

1. Check your vial concentration (e.g., 10 mg/mL or 20 mg/mL)
2. Confirm your dose in mg (e.g., 2.5 mg)
3. Convert to mL:
   Dose in mg÷Concentration in mg/mL=Volume in mL\text{Dose in mg} ÷ \text{Concentration in mg/mL} = \text{Volume in mL}Dose in mg÷Concentration in mg/mL=Volume in mL
4. Convert to units:
   mL×100=Units on syringe\text{mL} × 100 = \text{Units on syringe}mL×100=Units on syringe
5. Double-check your math before injecting

FAQs

Q: Is 2.5 mg the same as 25 units?
Only if your vial is 10 mg/mL. If your vial is 20 mg/mL, 2.5 mg = 12.5 units.

Q: Why does tirzepatide use mg instead of units?
Tirzepatide is dosed by weight (mg), not bioactivity like insulin, which is measured in international units.

Q: What if my syringe measures in mL instead of units?
1 mL = 100 units. So, 0.25 mL = 25 units. You can use either system as long as your math is correct.

Q: Can I switch vial strengths from 10 mg/mL to 20 mg/mL?
Yes—but you must recalculate your dose. For example, 2.5 mg = 25 units (10 mg/mL) or 12.5 units (20 mg/mL).

Summary

Tirzepatide dosing can be confusing if you’re using insulin-style syringes with compounded medication. Always confirm your vial concentration, dose in mg, and use a clear conversion formula. Incorrect dosing can lead to poor results or side effects.