Disclaimer: This article is for informational purposes only and does not constitute medical advice. It is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of a physician or other qualified health provider with any questions you may have regarding a medical condition.
Overview
Tirzepatide is a prescription medicine injected under the skin once a week. Health Canada has authorized it under two brand names, both made by Eli Lilly Canada: Mounjaro for type 2 diabetes and Zepbound for chronic weight management.
Both brands contain the same active ingredient in the same strengths, from 2.5 mg to 15 mg. What differs is the condition each one is approved to treat, and that affects which drug plans will pay for it.
Tirzepatide is available in Canada by prescription only. Only products that carry a Drug Identification Number (DIN) have been reviewed by Health Canada.
Health Canada has approved tirzepatide for two main uses, under separate brand names.
- Mounjaro: along with diet and exercise, to improve blood sugar control in adults with type 2 diabetes. It can be used alone or with metformin, a sulfonylurea, an SGLT2 inhibitor or basal insulin.
- Zepbound: along with a reduced-calorie diet and increased physical activity, for chronic weight management in adults with a BMI of 30 or more, or a BMI of 27 to less than 30 with at least one weight-related condition such as high blood pressure, abnormal cholesterol, prediabetes, type 2 diabetes, obstructive sleep apnea or cardiovascular disease.
In June 2026 Health Canada also authorized Zepbound for obstructive sleep apnea in adults with obesity.
Tirzepatide should not be used together with a GLP-1 receptor agonist such as semaglutide, or with a DPP-4 inhibitor.
Tirzepatide
GIP and GLP-1 receptor agonist
weight management
Prescription required
Available
How Tirzepatide Works
Tirzepatide acts on two hormone receptors involved in blood sugar and appetite: GIP and GLP-1.
By activating these receptors it helps the pancreas release insulin when blood sugar is high, slows how quickly the stomach empties, and reduces appetite. Together these effects lower blood sugar and, in most people, body weight.
Dosage Instructions of Tirzepatide
Tirzepatide is injected under the skin once a week, on the same day each week. The dose is raised gradually so the body can adjust.
The usual starting dose is 2.5 mg once weekly for 4 weeks. It is then increased to 5 mg once weekly. If more effect is needed, the dose can go up in 2.5 mg steps, with at least 4 weeks at each dose, to a maximum of 15 mg once weekly.
For weight management, the recommended maintenance doses of Zepbound are 5 mg, 10 mg or 15 mg once weekly.
If you miss a dose, take it as soon as possible within 4 days (96 hours). If more than 4 days have passed, skip it and take the next dose on your usual day. The day of the week can be changed as long as doses are at least 3 days (72 hours) apart.
In Canada tirzepatide comes as a KwikPen that holds four weekly doses. Mounjaro is also authorized as single-dose pens and vials. Your prescriber chooses the dose; this page is general information, not dosing advice.
Storage Instructions
Keep tirzepatide in the refrigerator at 2°C to 8°C. Do not freeze it, and protect it from light. If needed, a KwikPen can be kept unrefrigerated, at no more than 30°C, for up to 30 days. Single-dose Mounjaro pens and vials can be kept unrefrigerated for up to 21 days.
Side Effects of Tirzepatide
Stomach and bowel symptoms are the most common side effects. They happen most often while the dose is being increased. In the Zepbound weight-management trials they were reported as follows:
- Nausea: 25% to 29% of people, compared with 9% on placebo
- Diarrhea: 19% to 23%, compared with 8% on placebo
- Constipation: 11% to 17%, compared with 5% on placebo
- Vomiting: 8% to 13%, compared with 2% on placebo
- Abdominal pain and indigestion: about 9% to 10% each
- Injection site reactions: 6% to 8%
- Fatigue: 5% to 7%, and hair loss: 4% to 5%
Get medical help right away for severe stomach pain that does not go away, pain in the upper right abdomen with fever or yellowing of the skin, signs of an allergic reaction, or a lump or swelling in the neck.
People who also take insulin or a sulfonylurea have a higher risk of low blood sugar.
Important Safety Information About Tirzepatide
Tirzepatide carries a boxed warning about thyroid C-cell tumours. These tumours occurred in rats. It is not known whether tirzepatide causes them in people.
Do not use tirzepatide if you:
- have a personal or family history of medullary thyroid carcinoma (MTC)
- have Multiple Endocrine Neoplasia syndrome type 2 (MEN 2)
- are pregnant (Mounjaro is also not to be used while breastfeeding)
- are allergic to tirzepatide or any ingredient in the product
Stop tirzepatide at least 1 month before a planned pregnancy.
Pancreatitis and gallbladder problems have been reported. Vomiting and diarrhea can cause dehydration, which may harm the kidneys, so tell your doctor if you cannot keep fluids down.
Suicidal thoughts and behaviour have been reported with weight-management medicines. Tell your doctor about any new or worsening depression or unusual changes in mood.
Drug Interactions
Tirzepatide slows stomach emptying, which can change how medicines taken by mouth are absorbed.
- Birth control pills: tirzepatide can lower the level of oral contraceptives in the body. Switch to a non-oral method or add a barrier method for 4 weeks after starting and for 4 weeks after each dose increase.
- Insulin and sulfonylureas: the risk of low blood sugar is higher, and the dose of these medicines may need to be reduced.
- Other GLP-1 receptor agonists and DPP-4 inhibitors: should not be used together with tirzepatide.
- Medicines that raise heart rate: use with caution.
Give your doctor and pharmacist a full list of your medicines and supplements.
Brands & DIN Number of Tirzepatide
Brand Names
- Mounjaro
- Mounjaro KwikPen
- Zepbound
DIN (Drug Identification Numbers)
- 02557509
- 02557517
- 02557525
- 02557533
- 02557541
- 02557568
- 02551950
- 02551969
- 02551977
- 02551985
- 02551993
- 02552000
Key Takeaways
- 1Tirzepatide is a once-weekly injection sold in Canada as Mounjaro (type 2 diabetes) and Zepbound (weight management).
- 2It acts on two hormone receptors, GIP and GLP-1, to lower blood sugar and appetite.
- 3Dosing starts at 2.5 mg weekly and is raised gradually to a maximum of 15 mg weekly.
- 4Nausea, diarrhea, constipation and vomiting are the most common side effects.
- 5It must not be used in pregnancy or by people with a history of MTC or MEN 2.
- 6It can make birth control pills less effective for 4 weeks after starting and after each dose increase.
- 7It is prescription only. In BC, PharmaCare was reviewing Zepbound for coverage in mid-2026.
Frequently Asked Questions
Avee Editorial
Avee Editorial Team