Tirzepatide Calculator
Also known as: Mounjaro, Zepbound
What is Tirzepatide?
Tirzepatide is a dual GIP/GLP-1 receptor agonist marketed by Eli Lilly under the brand names Mounjaro (type 2 diabetes) and Zepbound (chronic weight management). Clinical protocols typically start at 2.5 mg once weekly with stepwise titration in 2.5 mg increments every four weeks up to a 15 mg maintenance dose. Compounded tirzepatide is supplied in lyophilized vials of 5 mg through 60 mg; reconstitution volume varies with vial size and target dose. The drug must be drawn with an insulin syringe — a 2.5 mg dose at 10 mg / 2 mL concentration equals 50 units on a U-100 syringe.
| 5 mg | lyophilized powder |
| 10 mg | lyophilized powder |
| 15 mg | lyophilized powder |
| 20 mg | lyophilized powder |
| 30 mg | lyophilized powder |
| 60 mg | lyophilized powder |
| 2.5 mg | ≈ 50 U-100 units (at 10mg / 2mL) |
| 5 mg | ≈ 100 U-100 units (at 10mg / 2mL) |
| 7.5 mg | ≈ 150 U-100 units (at 10mg / 2mL) |
| 10 mg | ≈ 200 U-100 units (at 10mg / 2mL) |
| 12.5 mg | ≈ 250 U-100 units (at 10mg / 2mL) |
| 15 mg | ≈ 300 U-100 units (at 10mg / 2mL) |
How it's typically prepared
Reconstitute with bacteriostatic water by injecting slowly along the inner wall of the vial. Do not shake — swirl gently. Refrigerate the reconstituted solution at 2–8 °C and use within the period your provider specifies.
Tirzepatide Titration Schedule (Zepbound label)
Reference titration ladder from the Zepbound (tirzepatide) FDA prescribing label for chronic weight management. Maintenance options are 5 mg, 10 mg, or 15 mg once weekly. This schedule is informational; your provider may follow a different titration based on your response and tolerability.
| Starting week | Dose | Notes |
|---|---|---|
| Week 1 | 2.5 mg/ week | — |
| Week 5 | 5 mg/ week | — |
| Week 9 | 7.5 mg/ week | — |
| Week 13 | 10 mg/ week | — |
| Week 17 | 12.5 mg/ week | — |
| Week 21 | 15 mg/ week | Maintenance |
Source: Zepbound (tirzepatide) Prescribing Information — FDA
Frequently asked questions
- How many units of tirzepatide is 2.5 mg?
- On a U-100 insulin syringe, 2.5 mg of tirzepatide equals 50 units when the vial is reconstituted at 10 mg / 2 mL (5 mg/mL concentration). Adjust if your vial size or BAC water volume differs.
- How much BAC water do I add to a 10 mg tirzepatide vial?
- 2 mL is the most commonly used volume because it produces a 5 mg/mL concentration that maps cleanly to insulin syringe units. 1 mL or 3 mL are also valid — the calculator will convert.
- How long does a reconstituted tirzepatide vial last?
- Manufacturer guidance for reconstituted compounded tirzepatide is typically 28–30 days refrigerated, but follow the period printed on your specific vial.
- Can I use a regular syringe instead of an insulin syringe?
- An insulin syringe (U-100 or U-40) is strongly recommended because tirzepatide doses are small and require sub-millilitre precision. Larger syringes lack the resolution.
Where researchers source this
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Other GLP-1 peptides
PeptideDose is an educational reference. It is not medical advice and does not replace consultation with a licensed healthcare provider. Doses shown in presets are derived from published protocols and product labels — they are not personal recommendations.