Health Canada has approved four main medicines for long-term weight management: semaglutide (Wegovy), liraglutide (Saxenda), naltrexone-bupropion (Contrave) and orlistat (Xenical). They work in different ways and give different amounts of weight loss.
- They are meant for a BMI of 30 or more, or 27 or more with a weight-related health problem.
- GLP-1 injections give the largest average weight loss.
- Most are not covered by provincial plans for weight loss alone.
Obesity Canada’s clinical practice guidelines describe obesity as a chronic disease, and medication as one of three pillars of treatment alongside nutrition and activity, and in some cases surgery. If diet and exercise alone have not been enough, these are the options a Canadian doctor can prescribe, and what to expect from each.
Who qualifies
Weight management medicines in Canada are approved for adults with:
- A body mass index (BMI) of 30 or more, or
- A BMI of 27 or more with a weight-related condition such as type 2 diabetes, high blood pressure, high cholesterol or sleep apnea.
They are prescribed alongside changes to eating and activity, not instead of them. Your family doctor, a nurse practitioner or a weight management clinic can assess you; see our guide to weight loss clinics in Canada.
The approved options at a glance
| Medicine | How it works | Form | Typical average loss in trials |
|---|---|---|---|
| Wegovy (semaglutide) | GLP-1: reduces appetite, slows digestion | Weekly injection | About 15% |
| Saxenda (liraglutide) | GLP-1, shorter acting | Daily injection | About 8% |
| Contrave (naltrexone-bupropion) | Acts on brain reward and appetite pathways | Tablets twice daily | About 5–6% |
| Xenical (orlistat) | Blocks about a third of dietary fat absorption | Capsule with meals | About 3–5% |
Percentages are average total body weight loss in the main trials, including the effect of diet; individual results vary a lot.
Semaglutide (Wegovy)
The most effective of the four. It is injected once a week, with the dose increased monthly to reduce nausea. Our detailed guide to Ozempic and Wegovy covers results, side effects and coverage.
Liraglutide (Saxenda)
An older GLP-1 medicine injected daily. It works the same way as semaglutide but is less potent. Generic liraglutide has become available in Canada, which may make it cheaper.
Naltrexone-bupropion (Contrave)
A combination of naltrexone (used for alcohol and opioid dependence) and bupropion (an antidepressant and smoking-cessation aid). Together they reduce cravings and appetite. It can suit people whose eating is driven by cravings.
Side effects include nausea, constipation, headache, dizziness, trouble sleeping and dry mouth. It can raise blood pressure and is not suitable for people with uncontrolled high blood pressure, seizures, eating disorders, or those taking opioids.
Orlistat (Xenical)
The oldest option. It stops part of the fat you eat being absorbed, so it works only when meals contain fat.
The main side effects are digestive: oily stools, urgency and gas, especially after high-fat meals. Many people find this encourages them to eat less fat.
What about other options?
- Phentermine, common in the United States, is not currently marketed in Canada.
- Metformin, a diabetes drug, causes small weight loss but is not approved for weight management.
- Supplements sold for weight loss rarely have good evidence; see our review of fat loss supplements in Canada.
- Bariatric surgery remains the most effective long-term treatment for severe obesity and is covered by provincial health plans, though wait times vary by province.
Cost and coverage
Most provincial drug plans do not cover medicines prescribed only for weight management, though some private workplace plans do. Out-of-pocket costs range from under $100 a month for orlistat to several hundred dollars a month for GLP-1 injections. Ask your pharmacist for current prices; they vary between pharmacies and provinces.
Frequently asked questions
What is the most effective weight loss drug in Canada?
Among those approved for weight management, semaglutide (Wegovy) gives the largest average weight loss, about 15% over 68 weeks in trials.
Can my family doctor prescribe weight loss medication?
Yes. Family doctors and nurse practitioners can prescribe all of these if you meet the BMI criteria.
Are weight loss drugs covered by OHIP or other provincial plans?
Generally not for weight loss alone. Some private insurance plans cover them, so check your benefits.
Photo: Direct Media, StockSnap (public domain).
General information, not medical advice. All of these are prescription medicines; speak to your doctor about which, if any, suits you.
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