Canada · Side effects
GLP-1 side effects in Canada, drug by drug.
Short answer
Every GLP-1 drug authorized in Canada shares the same core side effects: nausea, diarrhoea, vomiting and constipation, mostly early on. The serious warnings — pancreatitis, gallbladder disease, dehydration and the thyroid C-cell warning — also apply across the class. Pick your drug below for detail.
By drug
| Drug | Ingredient | Side-effect page |
|---|---|---|
| Ozempic, Wegovy, Rybelsus, generics | Semaglutide | Ozempic and Wegovy side effects |
| Mounjaro, Zepbound | Tirzepatide | Mounjaro and Zepbound side effects |
| Saxenda, Victoza | Liraglutide | Liraglutide in Canada |
Reporting a side effect in Canada
Tell your prescriber or pharmacist first, then report to the Canada Vigilance Program.
How common GI side effects were in trials
Rates from each drug's main weight-management trial, drug vs placebo. Trials differ, so compare with care.
| Drug (trial) | Nausea | Diarrhea | Vomiting | Constipation |
|---|---|---|---|---|
| Saxenda (SCALE) | 39% vs 14% | 21% vs 10% | 16% vs 4% | 19% vs 9% |
| Wegovy (STEP 1) | 44% vs 17% | 32% vs 16% | 25% vs 7% | 23% vs 10% |
| Zepbound (SURMOUNT-1) | 25% to 33% vs 10% | 19% to 23% vs 7% | 8% to 12% vs 2% | 12% to 17% vs 6% |
Most GI effects are mild to moderate and most common while the dose is being increased. Severe or persistent stomach pain, signs of dehydration, or yellowing of the skin need prompt medical care.
Last reviewed October 15, 2026against Health Canada's Drug Product Database and SCALE, STEP 1 and SURMOUNT-1.
Related
Frequently asked questions
- Which GLP-1 causes the most nausea?
- In their main trials, nausea rates were roughly similar in range: about 39% on Saxenda, 44% on Wegovy and 25% to 33% on Zepbound, vs 10% to 17% on placebo.
- What are the most common GLP-1 side effects?
- Across semaglutide, tirzepatide and liraglutide, the labels list gastrointestinal effects first: nausea, diarrhoea, vomiting, constipation and abdominal pain, usually worst early in treatment.
- Which serious GLP-1 side effects matter most?
- Pancreatitis, gallbladder disease, dehydration-related kidney injury, low blood sugar with insulin or sulfonylureas, and the rodent thyroid C-cell tumour warning. Severe ongoing abdominal pain needs urgent care.
- Do generic GLP-1s have different side effects?
- No. Health Canada-authorized generic semaglutide has the same active ingredient and warnings as the brand.
- How do I report a GLP-1 side effect in Canada?
- Tell your prescriber or pharmacist and report to the Canada Vigilance Program (MedEffect Canada).
Sources
General information only — not medical, legal or regulatory advice. Peptide Confessions does not sell, source or recommend any product or vendor, and nothing here is dosing guidance. Speak with a licensed Canadian healthcare professional or pharmacist about any medication. Editorial process →