Ozempic and Wegovy are both semaglutide, a GLP-1 medicine that reduces appetite and slows digestion. Ozempic is approved in Canada for type 2 diabetes; Wegovy, at a higher dose, is approved for weight management.
- In trials, people lost about 15% of body weight on average over 68 weeks.
- Doses start low and rise every four weeks to limit nausea.
- Weight usually returns if it is stopped without lasting lifestyle changes.
Few medicines have changed the conversation about weight as quickly as semaglutide. In Canada, demand caused shortages of Ozempic in 2022 and 2023, and “Ozempic” has become shorthand for a whole class of drugs. Here is how it works, what the evidence shows and what to know about access in Canada.
How GLP-1 medicines work
GLP-1 (glucagon-like peptide-1) is a hormone your gut releases after eating. It tells the pancreas to release insulin when blood sugar is high, slows the emptying of the stomach, and acts on appetite centres in the brain to increase fullness. Natural GLP-1 lasts only minutes; semaglutide is modified to last about a week, so it is injected once weekly.
People on semaglutide often describe less “food noise”: fewer cravings and less thinking about food. That is the main driver of weight loss, rather than a change in metabolism.
Ozempic, Wegovy and Rybelsus
| Brand | Form | Approved in Canada for | Maximum dose |
|---|---|---|---|
| Ozempic | Weekly injection pen | Type 2 diabetes | 2 mg a week |
| Wegovy | Weekly injection pen | Chronic weight management | 2.4 mg a week |
| Rybelsus | Daily tablet | Type 2 diabetes | 14 mg a day |
Wegovy is approved for adults with a body mass index (BMI) of 30 or more, or 27 or more with a weight-related condition such as high blood pressure, type 2 diabetes or sleep apnea, alongside diet and activity.
What the trials showed
In the STEP 1 trial, published in the New England Journal of Medicine in 2021, adults without diabetes on semaglutide 2.4 mg lost an average of about 15% of their body weight over 68 weeks, compared with about 2% on placebo. Later research (SELECT) found fewer heart attacks and strokes in people with heart disease and overweight. When people stopped the drug in a follow-up study, they regained about two-thirds of the lost weight within a year.
Side effects
- Nausea, vomiting, diarrhea and constipation: very common, mainly when the dose is increased
- Bloating, burping and heartburn
- Fatigue and headache
- Gallbladder problems, including gallstones, partly due to rapid weight loss
- Rarely, pancreatitis: severe, persistent stomach pain that may spread to the back needs urgent care
- Loss of muscle along with fat
Protecting muscle
Up to a third or more of the weight lost on GLP-1 drugs can be lean tissue. Eating enough protein (roughly 1.2–1.6 g per kilogram of body weight a day) and doing resistance training two to three times a week help keep muscle. Our guide to preserving muscle while losing weight explains how.
Cost and coverage in Canada
- Ozempic for type 2 diabetes is covered by many provincial drug plans and private insurers, usually with criteria.
- Wegovy for weight management is generally not covered by provincial plans and costs several hundred dollars a month out of pocket. Some private plans cover it.
- Because a Canadian semaglutide patent was allowed to lapse, generic makers have been preparing Canadian versions from 2026, which may lower prices over time.
For an overview of every approved option, including Saxenda, Contrave and orlistat, see our guide to weight loss medications in Canada. Research versions of GLP-1 peptides, such as Vita SM5, are sold for laboratory research only and are not a substitute for a prescription.
Frequently asked questions
What is the difference between Ozempic and Wegovy?
Both are semaglutide. Ozempic is approved in Canada for type 2 diabetes up to 2 mg weekly; Wegovy is approved for weight management at up to 2.4 mg weekly.
How much weight do people lose on Wegovy?
About 15% of body weight on average over 68 weeks in the STEP 1 trial, though results vary widely between people.
Do you regain weight after stopping semaglutide?
Most people regain a large part of the weight within a year of stopping unless eating and activity habits have changed.
Photo: Brooke Lark, StockSnap (public domain).
General information, not medical advice. Semaglutide is a prescription drug in Canada; speak to your doctor or pharmacist about whether it suits you.
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