How to Understand Your Tirzepatide Dosage: 10mg/mL vs 20mg/mL
If you're using Tirzepatide for weight loss or blood sugar control, understanding your injection dosage is essential—especially when using a compounded version. Tirzepatide vials often come in different strengths, such as 10mg/mL or 20mg/mL, and it's important to know how this affects the number of units you inject each week.
Getting the dose wrong could mean you're not getting enough medication—or getting too much. This guide will help you understand how to correctly measure and inject your weekly Tirzepatide dose, based on the strength of your medication.
What Does "mg/mL" Mean in Tirzepatide?
When you see 10mg/mL or 20mg/mL on your Tirzepatide vial, this tells you how concentrated the medication is:
10mg/mL means each 1 mL of liquid contains 10mg of Tirzepatide
20mg/mL means each 1 mL of liquid contains 20mg of Tirzepatide
The higher the concentration, the less volume you need to inject to get your prescribed weekly dose.
This is especially important when using an insulin syringe, which is measured in units, where:
1 mL = 100 units
0.5 mL = 50 units
0.25 mL = 25 units
Tirzepatide Injection Dosage by Vial Strength (10mg/mL vs 20mg/mL)
Here’s how your weekly Tirzepatide injection changes depending on the strength of your vial:
If your prescribed dose is 5mg once weekly:
Tirzepatide Vial Strength | How Many mL? | How Many Units to Inject |
10mg/mL | 0.50 mL | 50 units |
20mg/mL | 0.25 mL | 25 units |
If your prescribed dose is 10mg once weekly:
Vial Strength | mL to Inject | Units |
10mg/mL | 1.0 mL | 100 units |
20mg/mL | 0.5 mL | 50 units |
If your prescribed dose is 12.5mg once weekly:
Vial Strength | mL to Inject | Units |
10mg/mL | 1.25 mL | 125 units* |
20mg/mL | 0.625 mL | 62.5 units |
*Note: Most insulin syringes only hold 100 units, so doses over 100 units require a higher-concentration vial or split injections.
Why Tirzepatide Dosage by Units Matters
Many patients misunderstand the difference between milligrams (mg) and units. Your doctor will prescribe Tirzepatide based on milligrams, but you inject based on units, using the syringe markings.
If you switch vial strengths (from 10mg/mL to 20mg/mL, for example), your milligram dose stays the same, but the number of units to inject changes.
Injecting the wrong amount of units could mean you're underdosing or overdosing, both of which can lead to poor results or side effects.
Quick Formula for Tirzepatide Dose Conversion
To calculate how many units to inject based on your prescription:
[Prescribed Dose in mg] ÷ [Vial Strength in mg/mL] = Volume in mL
Volume in mL × 100 = Units to Inject
Example:
You’re prescribed 7.5mg weekly, and your vial is 20mg/mL
7.5 ÷ 20 = 0.375 mL
0.375 mL × 100 = 37.5 units
What If My Tirzepatide Vial Strength Changes?
If your compounded pharmacy switches you from a 10mg/mL vial to a 20mg/mL vial (which is common to reduce injection volume), the medication is exactly the same—it’s just more concentrated.
You’ll draw up fewer units to get the same therapeutic dose. For this reason, it's important to:
Always check your vial’s strength
Read the instructions on your prescription label
Use the correct number of units for your current vial
Final Tip for Safe Tirzepatide Injections
Never assume your dose in units is the same if your vial strength changes
Always confirm your Tirzepatide dosage in mg and vial concentration before injecting
Contact your provider or pharmacy if anything is unclear—especially if you're new to GLP-1 medications