Pillar
Weight Loss Medications
Anti-obesity medications can be an evidence-based tool for eligible patients when combined with nutrition, activity, and follow-up care.
Health Canada approved weight loss medications
These are currently marketed anti-obesity medications in Canada that may be considered for eligible adults. Your clinician helps match medication choice to your medical history, goals, and tolerability.
Injection pen
Wegovy
semaglutide 2.4 mg once weekly
Typical efficacy
In the STEP 1 trial (68 weeks), average weight loss was about 14.9% of starting body weight versus 2.4% with placebo.
Estimated monthly cost (CAD)
About CAD $480-$550/month
Common side effects
- Nausea, vomiting, constipation, or diarrhea
- Fullness, reduced appetite, or reflux
- Possible gallbladder symptoms
Important contraindications
- Pregnancy
- Personal or family history of medullary thyroid carcinoma
- Multiple endocrine neoplasia syndrome type 2 (MEN2)
- Caution with prior pancreatitis
Injection pen
Zepbound
tirzepatide once weekly
Typical efficacy
In SURMOUNT-1 (72 weeks), average weight loss was around 15% to 21% depending on dose, compared with about 3% with placebo.
Estimated monthly cost (CAD)
About CAD $350-$510/month
Common side effects
- Nausea, diarrhea, constipation, and reduced appetite
- Abdominal discomfort or reflux
- Possible gallbladder or dehydration-related symptoms
Important contraindications
- Pregnancy
- Personal or family history of medullary thyroid carcinoma
- Multiple endocrine neoplasia syndrome type 2 (MEN2)
- Caution with prior pancreatitis
Daily injection pen
Saxenda
liraglutide 3.0 mg daily
Typical efficacy
In the SCALE trial (56 weeks), average weight loss was about 8.0% versus 2.6% with placebo when combined with lifestyle support.
Estimated monthly cost (CAD)
About CAD $420-$560/month
Common side effects
- Nausea, vomiting, constipation, or diarrhea
- Injection-site irritation
- Headache or fatigue during dose escalation
Important contraindications
- Pregnancy
- Personal or family history of medullary thyroid carcinoma
- Multiple endocrine neoplasia syndrome type 2 (MEN2)
- Caution with prior pancreatitis
Oral tablets
Contrave
naltrexone / bupropion extended release
Typical efficacy
In COR-I (56 weeks), average weight loss was about 6.1% versus 1.3% with placebo. Nearly half of patients reached at least 5% weight loss.
Estimated monthly cost (CAD)
About CAD $250-$390/month
Common side effects
- Nausea, constipation, headache, or dry mouth
- Insomnia or jitteriness
- Possible increase in blood pressure or heart rate
Important contraindications
- Uncontrolled high blood pressure
- Seizure disorder or eating disorder history
- Current opioid use or opioid withdrawal
- Concurrent MAOI use
- Pregnancy
Cost ranges are cash-pay estimates from Canadian listings and may vary by dose, pharmacy, province, and insurance coverage. Data reviewed on February 23, 2026.
Why medication is a tool
Obesity is a chronic, relapsing disease. For some people, medication can reduce biological drivers of regain and support safer long-term outcomes.
When medication may be considered
- Weight-related medical conditions are present (for example diabetes, sleep apnea, hypertension, fatty liver).
- Lifestyle-only attempts have not produced durable results.
- The benefits and risks are reviewed in a shared decision-making discussion.
What medication is not
Medication is not a replacement for food structure, activity, sleep, and stress management. It is one tool inside a broader plan.
Practical expectations
- Start low and titrate based on tolerance and response.
- Monitor side effects, weight trend, and metabolic markers.
- Reassess fit regularly; the plan can change over time.
Discuss at your consult
Bring your medication history, goals, insurance questions, and concerns about side effects so the plan can be tailored.
References
- Pharmacologic Treatment of Overweight and Obesity in Adults (Endotext (updated 2024)) Link
- Semaglutide in Adults with Overweight or Obesity (STEP 1) (New England Journal of Medicine (2021)) Link
- Tirzepatide Once Weekly for the Treatment of Obesity (SURMOUNT-1) (New England Journal of Medicine (2022)) Link
- A Review of Current Guidelines for the Treatment of Obesity (American Journal of Managed Care (2022)) Link
- Canadian Adult Obesity Clinical Practice Guidelines (Obesity Canada (2020)) Link