Weight-loss medications available in Ontario (August 2025): how they compare

Ontario patients have several Health Canada–authorized choices for long-term weight management. Picking among them is about match and monitoring: the right dose, route, and schedule for your goals and medical history, plus a plan for nutrition, activity, sleep, and relapse-proofing.

It's also important to note that some things are popular in the media and are available in the US but not in Ontario or Canada.

What’s available

Weekly injectables: semaglutide 2.4 mg (Wegovy) and tirzepatide (Zepbound). Semaglutide is also known as Ozempic but that's branded and marketed for diabetes management.These are first-line for many because they produce the largest average weight loss in trials and often improve blood sugar, blood pressure, and lipids. Daily injectable liraglutide 3 mg (Saxenda) is effective as well, though with smaller average weight changes. Oral options include naltrexone/bupropion (Contrave) and orlistat (Xenical). Setmelanotide (Imcivree) is approved for rare genetic forms of obesity and is not used for common obesity. Phentermine exists in Canada as a short-term option; phentermine/topiramate (Qsymia) is not approved here.

How the top options differ

Wegovy (semaglutide 2.4 mg weekly - aka Ozempic). Strong average weight loss with familiar gastrointestinal effects during dose escalation (nausea, vomiting, diarrhea/constipation). Slow titration helps. Many patients also see improvements in blood pressure, A1c, and triglycerides. Coverage and supply vary by plan and region.

Zepbound (tirzepatide weekly). Dual incretin (GIP/GLP-1) activity with top-tier average weight loss. Side effects are similar to GLP-1 agents; gradual dose steps are part of the protocol. Early real-world reports mirror trial efficacy when adherence is good.

Saxenda (liraglutide 3 mg daily). Effective daily GLP-1 with smaller average losses than the weekly options, but a useful alternative when weekly agents are not preferred or tolerated. Pediatric use exists in defined circumstances.

Contrave (naltrexone/bupropion oral). An appetite/reward pathway medicine with modest average weight loss compared to incretin-based drugs. It can be a fit when injectables aren’t an option, but it is not for everyone: screen for seizure risk, blood pressure, and drug interactions.

Xenical (orlistat oral). Blocks fat absorption. Average weight loss is modest and depends heavily on diet. The trade-offs are gastrointestinal side effects if dietary fat is high and the need to space it from other medications; fat-soluble vitamin intake may need attention.

Setmelanotide. Reserved for genetically confirmed forms of obesity (for example, Bardet-Biedl syndrome). Access runs through specialist programs.

How to choose

Effectiveness versus fit. Weekly injectables deliver the largest average effect. If a weekly injection suits your routine and you tolerate the titration, these drugs often make appetite control more predictable. If you prefer oral medication or cannot use injectables, Contrave or orlistat are alternatives with lower average weight loss.

Medical context

If you live with type 2 diabetes, fatty liver disease, or sleep apnea, the metabolic improvements seen with incretin-based options can be a meaningful part of your overall care. If you have uncontrolled hypertension or certain neurologic risks, some oral options may not be suitable.

Product monographs and shared decision making matter here.

Monitoring and expectations.

Tolerability is best with slow titration for GLP-1 and dual-incretin therapies. With orlistat, dietary coaching is the key to avoiding GI issues. With Contrave, blood pressure and mood history should be reviewed. No medication replaces the basics: protein-anchored meals, fiber, activity, adequate sleep, and a plan for holidays, travel, and stressful weeks.

What isn’t available

Qsymia (phentermine/topiramate) is not approved in Canada as of August 2025. Compounded “alternatives” that claim to copy brand-name drugs should be avoided; stick to authorized products dispensed through regulated pharmacies.

Bottom line

Ontario patients can choose among several approved options, led by weekly injectables for the strongest average effect. The best plan is the one you can stick with, that fits your medical history, and that you can monitor safely. Medications work best alongside a simple, sustainable routine you can keep on good days and stressful ones.

Serving patients across Kitchener, Waterloo, Cambridge, Guelph, and surrounding communities including the Toronto/GTA corridor and London, Ontario.

References

1. STEP and SELECT program updates for semaglutide in chronic weight management and cardiometabolic risk. N Engl J Med. 2021–2024.

2. SURMOUNT trials: tirzepatide for chronic weight management. N Engl J Med. 2022–2024.

3. Health Canada regulatory summaries and product monographs: Wegovy, Zepbound, Saxenda. 2022–2025.

4. Contrave (naltrexone/bupropion) clinical development and monograph updates. 2018–2024.

5. Orlistat efficacy and safety reviews in long-term use. Obes Rev. 2017–2023.

6. Setmelanotide in rare genetic obesity: regulatory assessments and clinical outcomes. 2020–2024.