- Semaglutide is the drug in Ozempic (for diabetes) and Wegovy (for weight). Both are prescription medicines in Canada.
- In the main trial, people lost about 15% of body weight on average over 68 weeks at the weight-loss dose.
- Nausea and other stomach effects are common, especially when doses go up; serious risks include pancreatitis and gallbladder problems.
- Most weight returns after stopping unless habits change, so it’s usually treated as long-term therapy.
Semaglutide has changed weight-loss medicine, and Canada has been at the centre of the story, from early approvals to the arrival of generics after patent protection ended. This guide explains how it works, what the evidence shows, the side effects, and how Canadians can access it.
What is semaglutide?
Semaglutide mimics GLP-1, a gut hormone released after eating. It slows stomach emptying, increases fullness, reduces appetite and cravings, and helps the pancreas release insulin when blood sugar is high. It’s injected once a week.
- Ozempic is approved in Canada for type 2 diabetes, with doses up to 2 mg weekly.
- Wegovy is approved for chronic weight management, at up to 2.4 mg weekly.
What the evidence shows
In the STEP 1 trial, adults with obesity or overweight taking 2.4 mg weekly lost about 15% of their body weight on average over 68 weeks, compared with about 2% on placebo, alongside lifestyle advice. Later research found a reduction in major cardiovascular events in people with heart disease and overweight. Some of the weight lost is lean mass, which is why resistance training and protein matter during treatment.
Clinical reference doses
Treatment starts low and increases gradually to reduce side effects: typically 0.25 mg weekly for four weeks, then stepping up every four weeks to a maintenance dose of 1 to 2 mg (Ozempic) or 2.4 mg (Wegovy), as tolerated.
Side effects
- Nausea, vomiting, diarrhea and constipation, most common when increasing the dose
- Reduced appetite to the point of under-eating protein
- Gallbladder problems, including gallstones
- Pancreatitis (rare): severe abdominal pain needs urgent care
- Not for people with a personal or family history of medullary thyroid cancer or MEN2
Severe, persistent abdominal pain, especially spreading to the back, with or without vomiting, needs emergency assessment.
When you stop
In an extension of the STEP 1 trial, people who stopped regained about two thirds of the lost weight within a year. Appetite returns when the drug is gone. That’s why doctors usually plan semaglutide as long-term treatment, alongside diet, activity and strength training.
Access, cost and generics in Canada
- Prescription: family doctors, weight-management clinics and some telehealth services prescribe it after assessment.
- Coverage: Ozempic may be covered by provincial plans for type 2 diabetes under specific criteria; coverage for weight loss is mostly through private insurance, and plans vary.
- Generics: Novo Nordisk’s Canadian patent protection lapsed, and regulatory data protection ended in early 2026, opening the door to lower-cost generic semaglutide. Ask your pharmacist what’s available.
See our guide to Canadian weight loss clinics.
Research peptides
Semaglutide is also sold as a research peptide in freeze-dried vials, which must be mixed with bacteriostatic water and measured carefully. We stock SM5 (5 mg vials) and SM5 10 mg; our peptides page has a mixing calculator. These aren’t the same as pharmacy pens, and medical supervision is strongly recommended.
Legal status
Semaglutide is on Health Canada’s Prescription Drug List.
Frequently asked questions
How much weight can you lose on semaglutide?
About 15% of body weight on average over 68 weeks at 2.4 mg weekly in the STEP 1 trial, with wide individual variation.
Is Ozempic covered in Canada?
Provincial plans may cover it for type 2 diabetes under criteria. Coverage for weight loss is mainly through private plans.
What’s the difference between Ozempic and Wegovy?
Same drug. Ozempic is approved for type 2 diabetes up to 2 mg; Wegovy for weight management up to 2.4 mg.
Do you regain weight after stopping semaglutide?
Most people regain a large share within a year without ongoing treatment or lasting habit changes.
Is generic semaglutide available in Canada?
Patent and data protection ended, allowing generics. Ask your pharmacist about current availability.
Products mentioned in this guide
This article is general information for adults in Canada, not medical advice. Talk to a doctor or pharmacist before using any prescription drug, anabolic steroid or research compound, and get bloodwork done. If you’re in crisis, call or text 9-8-8 (Suicide Crisis Helpline) any time.
