Mounjaro vs Ozempic: which works better, and which one you can get for weight loss in Canada

Mounjaro vs Ozempic in one minute

Mounjaro vs Ozempic is a fight between two weekly injections, and tirzepatide wins it on weight loss. When the two drugs were given at full strength to adults with obesity, the tirzepatide group lost about 6.5 points more of their body weight and about 5 cm more off the waist¹.

Most people searching this in Canada miss one thing. Neither brand name is the one Health Canada authorized for weight loss. Mounjaro’s Canadian label covers type 2 diabetes only², and so does Ozempic’s³.

If you want one of these drugs for weight, the brand to ask for is Zepbound (tirzepatide) or Wegovy (semaglutide)^4,5. Our Wegovy vs Ozempic page explains how those two semaglutide brands differ.

So the real choice for most readers is tirzepatide vs semaglutide. This page covers the head-to-head trial, the diabetes trial, side effects, what each costs in Canada and who should pick which. If you are still deciding between all the weight-loss drugs, not just these two, our guide to the best GLP-1 for weight loss covers the others.

In Canada, neither Mounjaro nor Ozempic is a weight-loss brand

Each drug company sells its molecule under two names in Canada: one for diabetes, one for weight. The pens look alike, but the label decides what a doctor is prescribing it for and what a drug plan may cover.

Molecule	Maker	Diabetes brand	Weight-management brand
Tirzepatide	Eli Lilly	Mounjaro	Zepbound
Semaglutide	Novo Nordisk	Ozempic (plus generic semaglutide)	Wegovy

Here is the paper trail. Health Canada issued Mounjaro’s notice of compliance on 2022-11-24, and its current monograph lists type 2 diabetes only, in adults and in children 10 to under 18^2,3.

Ozempic got its notice of compliance on 2018-01-04. Later updates added heart and kidney outcomes in type 2 diabetes, but none added weight management³.

The weight brands came separately. Wegovy was approved on 2021-11-23³. Its label covers chronic weight management in adults with a BMI of 30 or more, or 27 or more with at least one weight-related condition.

It also covers teens 12 to 17, lowering heart-attack risk in adults with heart disease, and (conditionally) a liver condition called MASH⁵. Zepbound followed on 2025-05-13 and reached pharmacies on 2025-07-09^3,6.

It is authorized for chronic weight management in adults and for moderate to severe obstructive sleep apnea in adults with obesity⁴. Our Zepbound Canada guide covers its cost and how to get it, and our Zepbound vs Wegovy comparison pits the two weight brands against each other.

What this means for you:

• Using Mounjaro or Ozempic for weight is off-label. A doctor may still prescribe it that way, but Health Canada did not review either brand for weight loss.
• Your drug plan may treat the brands differently. A plan that covers diabetes drugs may not cover weight-loss drugs, and the reverse. Ask the plan before you fill the script.
• Generic semaglutide is a diabetes product. Apo-Semaglutide and Dr. Reddy’s semaglutide are on Canadian shelves, but both are labelled for type 2 diabetes. The one generic approved for weight, Sevmia, was approved but not yet sold as of November 2026^6,3. No generic tirzepatide was on Health Canada’s list of generic submissions under review as of September 2026⁷.

Tirzepatide vs semaglutide: how each drug works

Both drugs copy gut hormones that tell your brain you are full and slow down how fast your stomach empties. Semaglutide copies one hormone, GLP-1.

Tirzepatide copies two, GLP-1 and GIP. That second target is the usual explanation for why tirzepatide does a bit more, though the trials measure the result, not the reason.

Both are weekly shots from a pre-filled pen, and both start low and climb slowly so your gut can adjust. The Canadian labels set the pace:

• Zepbound (tirzepatide): starts at 2.5 mg a week for 4 weeks, then goes up in 2.5 mg steps after at least 4 weeks on each dose⁴.
• Wegovy (semaglutide): starts at 0.25 mg a week and steps up every 4 weeks to 2.4 mg, which you reach after 16 weeks⁵.

That slow climb matters when you compare results. Nobody loses 20% in the first month. The big numbers in the trials below are measured after 68 to 72 weeks, well over a year.

We are quoting the monographs here, not giving dosing advice. Your prescriber sets the schedule.

One more thing about doses. The Ozempic label allows up to 2 mg a week, but the 2 mg pen is approved and has never been marketed, so the strongest Ozempic pen sold in Canada is 1 mg^8,6.

Apo-Semaglutide pens also go up to 1 mg, while the Wegovy weight dose is 2.4 mg^6,5. So “Ozempic for weight loss” in Canada often means a lower semaglutide dose than the weight trials used.

The head-to-head trial: SURMOUNT-5 results

SURMOUNT-5 is the large head-to-head trial that put tirzepatide and semaglutide against each other in people with obesity. It was published in the New England Journal of Medicine in 2025, and tirzepatide won on every weight measure it reported¹.

How it worked. The trial randomly split 751 adults with obesity and no type 2 diabetes into two groups. One got tirzepatide at the highest dose they could tolerate (10 or 15 mg a week).

The other got semaglutide at the highest dose they could tolerate (1.7 or 2.4 mg a week). Everyone was followed for 72 weeks¹.

Those semaglutide doses are the Wegovy doses, not Ozempic’s diabetes doses. So this was really Zepbound against Wegovy.

SURMOUNT-5, 72 weeks	Tirzepatide	Semaglutide
Average change in body weight	−20.2%	−13.7%
Average change in waist size	−18.4 cm	−13.0 cm
Lost at least 10%	87.7%	66.7%
Lost at least 15%	71.7%	45.0%
Lost at least 20%	55.0%	31.1%
Lost at least 25%	36.5%	18.6%

Weight and waist figures are least-squares means from the NEJM paper¹. The “lost at least” rows are observed values from the trial’s results on ClinicalTrials.gov⁹.

Let’s break it down. On average, people on tirzepatide lost about half as much again as people on semaglutide. The gap is wider at the top end: twice as many people on tirzepatide lost a quarter of their body weight.

Semaglutide still did well. Two in three people on it lost at least 10% of their body weight.

Three limits are worth knowing:

1. It was open-label. Everyone knew which drug they were on. That can nudge behaviour, though weight on a scale is hard to fake.
2. Eli Lilly paid for it. Lilly makes tirzepatide¹. The results went through a major journal and are posted in full on ClinicalTrials.gov⁹, which helps, but it is still a sponsor trial.
3. No one with type 2 diabetes was in it. In the placebo trials, people with diabetes lost less on both drugs: 14.7% on tirzepatide 15 mg in SURMOUNT-2 and 9.6% on semaglutide in STEP 2^4,5. Expect smaller numbers if you have diabetes.

What the placebo trials add: SURMOUNT-1 vs STEP 1

Before SURMOUNT-5, people compared the two drugs by lining up their separate trials against placebo. Here is that view, pulled from our data:

Tirzepatide vs semaglutide: best trial result, time to effect, how you take it, Canadian price and Health Canada status

Measure	Mounjaro / Zepbound (tirzepatide)	Ozempic / Wegovy (semaglutide)
What it is	GIP and GLP-1 receptor agonist	GLP-1 receptor agonist
Average weight loss	−20.9% in SURMOUNT-1, 72 weeks, 15 mg weekly	−14.9% in STEP 1, 68 weeks, 2.4 mg weekly
Placebo group	3.1%	2.4%
Time to full effect	~17 mo. Full dose after 20 weeks	~16 mo. Full dose after 16 weeks
How you take it	Weekly pen (easy)	Weekly pen (easy)
Cost per month	$314–742 cash, before insurance	$380–507 cash, before insurance
Health Canada	Approved (Zepbound)	Approved
Evidence grade	A: Several positive phase 3 trials (SURMOUNT-1 and -2) and approved for weight management in Canada as Zepbound.	A: Several positive phase 3 trials (STEP 1-3) and approved for weight management in Canada.

In SURMOUNT-1, tirzepatide 15 mg led to 20.9% weight loss at 72 weeks against 3.1% on placebo¹⁰. In STEP 1, semaglutide 2.4 mg led to 14.9% at 68 weeks against 2.4% on placebo¹¹. The pattern matches SURMOUNT-5, which is reassuring.

But side-by-side placebo trials have different people, lengths and sites, so the direct trial is the better evidence. That is why we lead with it.

Mounjaro vs Ozempic for type 2 diabetes: SURPASS-2

If you have type 2 diabetes, the Mounjaro vs Ozempic question is the one the Canadian labels were written for. SURPASS-2 tested it directly. Tirzepatide lowered blood sugar more than Ozempic’s 1 mg dose and led to more weight loss¹².

The trial enrolled 1,879 adults with type 2 diabetes for 40 weeks. They got tirzepatide 5, 10 or 15 mg, or semaglutide 1 mg¹². Here is what happened:

• A1C (average blood sugar) fell by 2.01, 2.24 and 2.30 points on the three tirzepatide doses, against 1.86 points on semaglutide¹².
• Weight fell more on tirzepatide, by 1.9 kg, 3.6 kg and 5.5 kg more than on semaglutide, depending on the dose¹².
• Low blood sugar was uncommon on both: 0.2% to 1.7% on tirzepatide and 0.4% on semaglutide¹².

Two cautions. The semaglutide dose was 1 mg, below the 2.4 mg Wegovy dose, so it does not show how tirzepatide compares with full-dose semaglutide in diabetes.

And it was 40 weeks, so it shows the early part of the curve. For people with diabetes, the fair summary is that both drugs work well and tirzepatide works a bit better on both sugar and weight.

Mounjaro vs Ozempic side effects

Side effects are close. Both drugs mostly upset the stomach, and most of it happens while the dose is still climbing. In SURMOUNT-5 the gut side effects were mostly mild to moderate on both drugs¹.

We worked out the rates below from the adverse-event counts posted for SURMOUNT-5 (374 people took tirzepatide, 376 took semaglutide)⁹:

Side effect in SURMOUNT-5	Tirzepatide	Semaglutide
Nausea	43.6%	44.4%
Constipation	27.0%	28.5%
Diarrhea	23.5%	23.4%
Vomiting	15.0%	21.3%
Acid reflux (GERD)	6.1%	10.6%
Burping	9.9%	7.7%
Hair loss	8.3%	6.1%
Injection-site reaction	8.6%	0.3%
Any serious adverse event	4.8%	3.5%

What stands out to us:

• Nausea is a coin flip on either drug. Close to half of people felt it at some point.
• Semaglutide had more vomiting and reflux. Tirzepatide had more injection-site redness or itching and slightly more hair loss.
• Few people dropped out over side effects. Six people in each group left the trial because of an adverse event⁹. More may have stopped the drug for a while and stayed in the trial, which the registry counts separately.

The diabetes trial told a similar story. In SURPASS-2, nausea hit 17% to 22% on tirzepatide and 18% on semaglutide, and diarrhea 13% to 16% against 12%. Serious adverse events were reported in 5% to 7% on tirzepatide and 3% on semaglutide¹².

The Canadian monographs carry the same main warning for both drugs: thyroid C-cell tumours seen in rodent studies^4,5. Ask your doctor what that warning means for you before you start either one.

Mounjaro vs Ozempic cost in Canada

At the starting doses, Ozempic usually costs a little less per pen than Mounjaro. At the top doses, tirzepatide gets expensive fast. These are cash prices for one pen (four weekly doses), including the pharmacy’s dispensing fee, before any insurance¹⁵.

Ozempic, Mounjaro, Wegovy and Zepbound cash prices in Canada

Brand (use in Canada)	Dose	What you get	Cash price	Basis
Ozempic (diabetes)	0.25 or 0.5 mg	1 pen, 4 weekly doses	$253–339	Estimated
Ozempic (diabetes)	1 mg	1 pen, 4 weekly doses	$262–325	Audited at some chains, rest estimated
Apo-Semaglutide (generic) (diabetes)	up to 1 mg	1 pen, 4 weekly doses	$92–123	Audited at 5 chains, rest estimated
Wegovy (weight)	any strength	1 pen, 4 weekly doses	$380–507	Audited at Costco, Walmart, London Drugs, Rexall and Shoppers; estimated elsewhere
Mounjaro (diabetes)	2.5 or 5 mg	1 pen, 4 weekly doses	$330–406	Audited at 3 chains, rest estimated
Mounjaro (diabetes)	7.5 or 10 mg	1 pen, 4 weekly doses	$458–561	Audited at 3 chains, rest estimated
Mounjaro (diabetes)	12.5 or 15 mg	1 pen, 4 weekly doses	$586–716	Audited at 3 chains, rest estimated
Zepbound (weight)	2.5 or 5 mg	1 pen, 4 weekly doses	$314–418	Estimated
Zepbound (weight)	7.5 or 10 mg	1 pen, 4 weekly doses	$439–581	Estimated
Zepbound (weight)	12.5 or 15 mg	1 pen, 4 weekly doses	$563–742	Estimated

“Audited” means the drug price comes from a published retail phone audit in August 2026. “Estimated” means it was modelled from list prices.

On every row the dispensing fee is a modelled figure, from $0 to $13.99 depending on the chain¹⁵. Zepbound has no audited Canadian price yet, so treat its rows as a guide, not a quote.

A few things change the real number you pay:

• Your dose. Tirzepatide’s price climbs with each step. In this data, Wegovy costs the same at every strength.
• Your drug plan. A plan can treat a diabetes brand and a weight-loss brand very differently, even when the drug inside is the same. Check your plan’s list before you choose.
• Where you fill it. In this data, Costco sat at the low end and Shoppers at the high end for the brands that were audited¹⁵.

Our guide to weight-loss injections in Canada covers how to get a prescription and where to fill it.

Which one should you ask your doctor about?

If weight loss is the goal and cost is not the main limit, the evidence points to tirzepatide, sold for weight as Zepbound. If you need the cheaper or better-covered option, semaglutide still does a lot. Here is how we would think about it in a few common cases.

• You have obesity and no diabetes. Ask about Zepbound or Wegovy, the two brands authorized for weight. SURMOUNT-5 favours Zepbound by about 6.5 points of body weight¹.
• You have type 2 diabetes. Mounjaro and Ozempic are both authorized for you, and your plan may cover them. SURPASS-2 favours Mounjaro on A1C and weight¹².
• Your budget is tight. At low doses the gap is small. At high doses tirzepatide costs more per pen. Generic Apo-Semaglutide is far cheaper, but it is labelled for diabetes and comes in pens up to 1 mg^15,6.
• You have heart disease. Wegovy is the one with a Canadian label for lowering the risk of a non-fatal heart attack in adults with established heart disease and a BMI of 27 or more⁵.
• You have sleep apnea and obesity. Zepbound is the one with a Canadian label for moderate to severe obstructive sleep apnea⁴.
• You did not get along with one of them. The side-effect rates are close, but they are not identical. Someone who vomited a lot on semaglutide may do better on tirzepatide, and the reverse. That is a conversation for your prescriber.

Not sure where you fit? Take our one-minute quiz and it will point you to the options that match your goals, budget and comfort with needles.

Switching from Ozempic to Mounjaro (or back)

Some people want to switch for price, coverage or side effects. There is no simple dose-for-dose swap between them in the Canadian labels. Both start at a low dose and step up every four weeks or more^4,5, so your prescriber decides where you restart.

Keep these points in mind if you are thinking about it:

• Expect some stomach side effects again while the new dose climbs. In SURMOUNT-5 they came mostly during the dose increases¹.
• Ask whether your plan treats the new brand the same way as the old one.
• Do not stack the two drugs or take one you were not prescribed.

How we compared Mounjaro and Ozempic

We read the trial papers so you do not have to, and we used the journal figure whenever a press release said something different. Every Health Canada status on this page was checked against the Drug Product Database and the Notice of Compliance database on 2026-11-12^6,3. Every Canadian price comes from one pricing dataset, and we say which rows were audited and which were estimated¹⁵.

We did not test these drugs on anyone, and no pharmacist has reviewed this page yet. It shows “Pharmacist review pending” until one does. You can read how we grade the evidence or go back to the full rankings of every weight-loss peptide to see where these two land against the rest.

This page is for information only. Talk to a doctor or pharmacist before you start, stop or switch any medication.