Tirzepatide Calculator
Calculate reconstitution and weekly dosing for Tirzepatide (Mounjaro/Zepbound) with the standard titration schedule.
New to Tirzepatide? Start Here
What is it? Tirzepatide is the active ingredient in Mounjaro and Zepbound. It's a weekly injection that helps with weight loss and blood sugar control.
How it works: It mimics two hormones (GIP and GLP-1) that reduce appetite and slow digestion, helping you feel full longer.
Key point: You inject once per week, same day each week. Always start at the lowest dose and increase slowly.
Tirzepatide Titration Schedule
Important: Increase your dose every 4 weeks. Don't skip steps - this prevents nausea and other side effects.
2.5mg
Weeks 1-4
Starting dose
5mg
Weeks 5-8
First increase
7.5mg
Weeks 9-12
Building up
10mg
Weeks 13-16
Therapeutic
12.5mg
Weeks 17-20
If needed
15mg
Week 21+
Maximum
Calculate Your Dose
Fill in your vial info, then select your current week
Check the label on your vial
How much water you added (ml)
Where you are in the schedule
Your Weekly Injection
Weekly Dose
2.5
mg per week
Draw This Much
50
units on syringe
Concentration
5000
mcg per ml
What does 50 units look like on a syringe?
Using a standard 100-unit insulin syringe (U-100)
How to Use This Calculator (Step by Step)
Check your vial
Look at the label on your Tirzepatide vial. It will say how many milligrams (mg) are in the vial. Common sizes are 5mg, 10mg, 15mg, 20mg, or 30mg. Select this from the dropdown.
Enter the water amount
How much bacteriostatic water (BAC water) did you add to the vial? The default is 2ml, which works well for most vials. If you added a different amount, change this number.
Select your current week
Choose which week of the titration schedule you're on. If you just started, select "Week 1-4". The calculator automatically sets your dose based on the standard schedule.
Read your results
The calculator shows how many units to draw on your insulin syringe. Look at the syringe visual below to see exactly where to fill to. Inject once per week, same day each week.
About Tirzepatide
Tirzepatide is the active ingredient in Mounjaro (for diabetes) and Zepbound (for weight loss). It's a newer medication that works differently than older weight loss drugs.
How It Works (Simple Explanation)
Your body naturally makes hormones that tell your brain "I'm full" after eating. Tirzepatide mimics two of these hormones:
- GIP - Helps your body process sugar and may directly affect fat cells
- GLP-1 - Reduces appetite and slows stomach emptying
Because it targets both hormones (unlike Semaglutide which only targets GLP-1), many people find it more effective for weight loss.
What to Expect
- Week 1-4: You may notice reduced appetite. Some people feel nauseous - this usually improves.
- Week 5-8: Most people see weight loss beginning. Appetite is noticeably reduced.
- Week 9+: Steady weight loss continues. You'll know which dose works best for you.
Important Safety Information
Tirzepatide is a prescription medication. This calculator is for educational purposes only. Always use under medical supervision. Do not use if you have a personal or family history of medullary thyroid cancer or Multiple Endocrine Neoplasia syndrome type 2.
Frequently Asked Questions
Tirzepatide is a dual GIP/GLP-1 agonist, while Semaglutide only targets GLP-1. Think of it like this: Semaglutide presses one button to reduce appetite, while Tirzepatide presses two buttons. In clinical trials, Tirzepatide showed greater average weight loss compared to Semaglutide.
Once per week, on the same day each week. For example, if you inject on Monday, always inject on Monday. You can inject at any time of day, with or without food. If you miss a dose, take it as soon as you remember if it's within 4 days. If more than 4 days have passed, skip that dose and continue your regular schedule.
Starting at a low dose and slowly increasing helps your body adjust and minimizes side effects like nausea, vomiting, and diarrhea. These GI side effects are most common when starting or increasing doses. By going slowly, most people can avoid severe side effects. Never skip ahead in the titration schedule.
If you experience significant nausea or other side effects when increasing your dose, you can stay at your current dose longer (8 weeks instead of 4) before moving up. You can also go back to the previous dose. Many people find an effective dose below the maximum - you don't have to reach 15mg. Talk to your healthcare provider about adjusting your schedule.
Tirzepatide is injected subcutaneously (under the skin, not into muscle). Common injection sites include:
- Stomach/abdomen (most common) - at least 2 inches from belly button
- Front of thighs
- Back of upper arms
Rotate injection sites each week to prevent skin irritation.