Two injectable medications dominate the weight loss conversation in Canada right now: Mounjaro (tirzepatide) and Ozempic (semaglutide). Both belong to the GLP-1 receptor agonist family, but Mounjaro adds a second mechanism that sets it apart. I've dug into the clinical data, talked to pharmacists across Canada, and compared real-world costs to help you understand the differences.
Quick Comparison
| Feature | Mounjaro | Ozempic |
| --- | --- | --- |
| Active ingredient | Tirzepatide | Semaglutide |
| Mechanism | Dual GIP + GLP-1 agonist | GLP-1 agonist |
| Manufacturer | Eli Lilly | Novo Nordisk |
| Injection frequency | Once weekly | Once weekly |
| Max dose | 15 mg/week | 2 mg/week |
| Avg weight loss (trials) | ~22.5% at highest dose | ~12-15% at 1-2 mg |
| Monthly cost (no insurance) | ~$300-$450 | ~$250-$340 |
| Canada approval | 2023 (T2D) | 2018 (T2D) |
How Mounjaro Works
Mounjaro (tirzepatide) is the first dual GIP/GLP-1 receptor agonist approved in Canada. It activates two incretin hormone receptors instead of one. GLP-1 slows gastric emptying and reduces appetite. GIP (glucose-dependent insulinotropic polypeptide) enhances insulin secretion and may independently affect fat metabolism.
This dual action is what researchers believe drives Mounjaro's higher weight loss numbers. Health Canada approved Mounjaro for type 2 diabetes in 2023. Eli Lilly has also sought approval for a weight management indication under the brand name Zepbound, which is available in the US but still pending in Canada as of early 2026.
Mounjaro doses range from 2.5 mg (starter) up to 15 mg per week, with several steps in between: 5 mg, 7.5 mg, 10 mg, 12.5 mg, and 15 mg.
How Ozempic Works
Ozempic (semaglutide) is a GLP-1 receptor agonist that has been available in Canada since 2018. It works by mimicking the GLP-1 hormone, which reduces appetite, slows stomach emptying, and improves blood sugar control. Ozempic is approved for type 2 diabetes but is widely prescribed off-label for weight management.
Standard Ozempic doses are 0.25 mg (starter), 0.5 mg, 1 mg, and 2 mg per week. Most patients find their maintenance dose at 0.5 mg or 1 mg. For a deeper look, read our guide to getting Ozempic in Canada.
Weight Loss Results
This is where Mounjaro stands out. The SURMOUNT-1 trial showed that tirzepatide at the 15 mg dose produced an average weight loss of 22.5% of body weight over 72 weeks. At the 10 mg dose, results were around 21.4%. At 5 mg, around 15%.
Ozempic's SUSTAIN trials showed weight loss of around 9.9% to 12.4% at the 1 mg dose. The 2 mg dose pushed closer to 15%. Head-to-head, tirzepatide produced significantly more weight loss at comparable dose levels.
That said, individual results vary widely. Some patients respond better to semaglutide, and some can't tolerate tirzepatide's side effects. Trial averages don't predict what will happen for you specifically.
Cost in Canada
| Cost Factor | Mounjaro | Ozempic |
| --- | --- | --- |
| Monthly retail | $300-$450 | $250-$340 |
| Annual cost | $3,600-$5,400 | $3,000-$4,080 |
| Insurance coverage | Growing; newer to market | Widely covered for T2D |
| Savings program | Lilly savings card available | Novo Nordisk patient support |
Ozempic is generally cheaper and more widely covered, thanks to its longer time on the Canadian market. Mounjaro's coverage is expanding, and Eli Lilly has introduced a savings card program in Canada that can reduce out-of-pocket costs. Read our Mounjaro Canada guide for more on costs and the savings card.
One more cost factor: generic semaglutide. Since May 2026, the Apotex and Dr. Reddy's generics sell for roughly $88 to $99 per month at Costco Pharmacy, far below brand Ozempic at $250 to $340. There is no generic tirzepatide, so Mounjaro stays at full brand price for now. That widens the cost gap on the Ozempic side. See our generic semaglutide guide.
Side Effects Comparison
Both medications share similar GI side effects, which is expected since they both act on GLP-1 receptors. Common side effects include:
- Nausea (most common, especially during dose escalation)
- Diarrhea
- Decreased appetite
- Vomiting
- Constipation
In the SURPASS trials, Mounjaro's GI side effects were comparable to Ozempic's at similar efficacy levels. Some patients report that Mounjaro causes more nausea during the initial dose escalation. Both medications carry warnings about pancreatitis and thyroid tumors.
Insurance and Coverage
Ozempic has a significant head start. It's listed on most provincial formularies for type 2 diabetes and is covered by the majority of private plans for that indication.
Mounjaro received Health Canada approval for type 2 diabetes in 2023 and is now being added to provincial formularies. Ontario, Quebec, and Alberta have started listing it. Private insurers are increasingly covering it, especially with the strong clinical data behind tirzepatide.
For weight loss specifically (without a diabetes diagnosis), neither medication is consistently covered. Some private plans make exceptions with special authorization. The Eli Lilly savings card can help offset Mounjaro costs regardless of insurance status.
Which Should You Choose?
Choose Mounjaro if: You want the highest possible weight loss, your insurance covers it, or you can use the Lilly savings card. The dual mechanism offers an edge in clinical trials.
Choose Ozempic if: You want a more established medication with broader insurance coverage and a lower out-of-pocket cost. Ozempic also has longer safety data and the SELECT cardiovascular outcomes trial behind it.
On cost specifically, the gap is now wider: generic semaglutide gives the Ozempic side an $88 to $99 per month option at Costco Pharmacy, while Mounjaro (tirzepatide) has no generic and stays at full brand price.
Many patients who don't respond well to one medication find success with the other. Talk to your doctor about both options.
Frequently Asked Questions
Is Mounjaro better than Ozempic for weight loss?
On average, yes. Clinical trials show tirzepatide produces greater weight loss than semaglutide at their respective maximum doses. The SURMOUNT trials showed roughly 22% weight loss vs. about 15% with Wegovy (semaglutide 2.4 mg). However, individual responses vary. Some people do better on Ozempic.
Can I switch from Ozempic to Mounjaro?
Yes, but since they're different molecules, your doctor will likely start you at a lower Mounjaro dose and escalate from there. There's no direct dose equivalence between the two.
Is Zepbound the same as Mounjaro?
Zepbound is the brand name for tirzepatide when used for weight management (similar to how Wegovy is semaglutide for weight loss). Zepbound is approved in the US but is not yet approved in Canada as of early 2026.