Tirzepatide calculator
A dual GIP and GLP-1 receptor agonist prescribed for type 2 diabetes and chronic weight management, dosed once weekly.
Also known as: Mounjaro, Zepbound
FDA status FDA-approved as a prescription drug (Mounjaro, Zepbound). Compounded tirzepatide is not FDA-approved and is not reviewed by FDA for safety, effectiveness, or quality.
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What Tirzepatide is
Tirzepatide is a dual agonist: a single molecule that activates both the GIP and GLP-1 receptors. That dual action is what distinguishes it from semaglutide, and in head-to-head trials it produced greater average weight loss.
Research depth: 5/5 Large body of research: the phase 3 SURPASS and SURMOUNT programs, including head-to-head human trials. Human trials: Large randomized trials. This measures how much has been studied — counting animal and laboratory work — not whether it works for you.
How Tirzepatide works
GLP-1 receptor activation drives glucose-dependent insulin release and appetite suppression, while GIP receptor activation appears to improve how fat tissue handles nutrients and may reduce the nausea burden relative to GLP-1 alone. The combination affects both blood glucose control and energy intake.
Tirzepatide side effects
Commonly reported
- Nausea, worst after each dose escalation
- Diarrhea, vomiting, or constipation
- Decreased appetite
- Indigestion and abdominal pain
- Injection-site reactions
Serious — seek medical care
- Pancreatitis — severe, persistent abdominal pain
- Gallbladder disease
- Hypoglycemia when combined with insulin or sulfonylureas
- Severe dehydration and kidney injury from prolonged GI losses
- Thyroid C-cell tumors in rodents — same contraindications as semaglutide
This list is not exhaustive. Report anything unexpected to the clinician who prescribed it. If you have severe abdominal pain, trouble breathing, or signs of an allergic reaction, seek care the same day. See also our guide to peptide side effects by class.
A worked example
A 10 mg vial reconstituted with 2 mL of bacteriostatic water gives 5 mg/mL. A 2500 mcg dose is then 0.5 mL — about 50 units on a 100-unit insulin syringe, giving roughly 4 doses per vial before accounting for residual volume left in the vial and syringe.
Prefer paper? Download the printable Tirzepatide dosing chart (PDF) — every vial size and water volume in syringe units, with the same review byline as this page. All charts →
Commonly cited dose range
Figures circulating for Tirzepatide run from 2500 mcg to 15000 mcg. Commonly discussed protocols begin at the lowest step and increase no faster than every four weeks. Weekly dosing.
Read this as reference information, not instruction. These numbers describe what is commonly discussed, not what is right for any individual. Dose, frequency, and whether to use Tirzepatide at all are decisions for a licensed clinician who knows your history.
Common questions
How many units is 2.5 mg of tirzepatide?
It depends entirely on the concentration. In a 10 mg vial reconstituted with 2 mL of bacteriostatic water (5 mg/mL), 2.5 mg is 0.5 mL — 50 units on a 100-unit insulin syringe. Change the water volume and that number changes.
How much water goes into a 10 mg tirzepatide vial?
Common choices are 1 mL or 2 mL. 2 mL yields 5 mg/mL, which puts typical starting doses in an easy-to-read range on an insulin syringe. The water volume is a measurement convenience, not part of the dose.
Can I use the same calculator for compounded and branded tirzepatide?
The arithmetic is identical for any lyophilized vial. Branded pens are pre-filled and pre-measured, so no reconstitution math applies to them at all.