If you are comparing Wegovy vs Mounjaro for weight loss, you are not alone. These are the two most talked-about GLP-1 injectable medications in Canada right now, and they work differently at the molecular level. Wegovy targets one gut hormone (GLP-1). Mounjaro targets two (GLP-1 and GIP). In clinical trials, Mounjaro produced greater average weight loss, but Wegovy has a longer track record and broader insurance coverage in Canada. This guide breaks down the clinical data, costs, side effects, and real-world differences so you can have an informed conversation with your doctor.

This article is for informational purposes only and does not constitute medical advice. Always consult a qualified healthcare provider before starting, stopping, or changing any medication. The information below should not replace a one-on-one consultation with your physician or pharmacist.

How Do Wegovy and Mounjaro Work?

Both Wegovy and Mounjaro belong to the GLP-1 receptor agonist family, but they are not the same drug.

Wegovy (semaglutide) mimics a single gut hormone called GLP-1. When you eat, your body naturally releases GLP-1 to signal fullness to your brain. Wegovy amplifies that signal. It slows gastric emptying, reduces appetite, and helps your body regulate blood sugar. Novo Nordisk manufactures Wegovy, and Health Canada approved it for chronic weight management in 2022.

Mounjaro (tirzepatide) takes a dual approach. It mimics both GLP-1 and another gut hormone called GIP (glucose-dependent insulinotropic polypeptide). This "twincretin" mechanism appears to produce stronger effects on appetite, blood sugar, and fat metabolism. Eli Lilly manufactures Mounjaro, and Health Canada approved it for type 2 diabetes in 2023, with weight management approval (under the brand name Zepbound in some markets) following shortly after.

The simplest way to understand the difference: Wegovy pushes one lever. Mounjaro pushes two.

Head-to-Head Comparison

| Feature | Wegovy | Mounjaro |

|---|---|---|

| Active Ingredient | Semaglutide | Tirzepatide |

| Dose Range | 0.25 mg to 2.4 mg weekly | 2.5 mg to 15 mg weekly |

| Mechanism | GLP-1 receptor agonist | Dual GIP/GLP-1 receptor agonist |

| Health Canada Approval (Obesity) | November 2022 | 2024 |

| Manufacturer | Novo Nordisk | Eli Lilly |

| Administration | Once-weekly subcutaneous injection | Once-weekly subcutaneous injection |

| Dose Escalation Period | 16–20 weeks | 20–28 weeks |

Both drugs require a prescription. Neither is available over the counter in Canada.

Clinical Trial Results: What Does the Science Say?

Both Wegovy and Mounjaro have been studied in large, rigorous clinical trial programs. Wegovy's data comes from the STEP trial series. Mounjaro's data comes from the SURMOUNT trial series.

STEP Trials (Wegovy / Semaglutide)

The STEP 1 trial enrolled 1,961 adults with obesity or overweight with at least one weight-related condition. Participants received semaglutide 2.4 mg weekly or placebo for 68 weeks. The semaglutide group lost an average of 14.9% of their body weight, compared to 2.4% in the placebo group (1).

For someone weighing 100 kg (220 lbs), that translates to roughly 15 kg (33 lbs) of weight loss.

SURMOUNT Trials (Mounjaro / Tirzepatide)

The SURMOUNT-1 trial enrolled 2,539 adults with obesity or overweight. Participants received tirzepatide at doses of 5 mg, 10 mg, or 15 mg weekly, or placebo, for 72 weeks. The results were:

  • Tirzepatide 5 mg group: 15.0% body weight loss
  • Tirzepatide 10 mg group: 19.5% body weight loss
  • Tirzepatide 15 mg group: 20.9% body weight loss
  • Placebo group: 3.1% body weight loss (2)

At the highest dose, participants lost more than one-fifth of their body weight. For someone starting at 100 kg, that is roughly 21 kg (46 lbs).

Clinical Trial Results Comparison

| Trial | Drug | Dose | Avg Weight Loss (%) | Duration | Participants |

|---|---|---|---|---|---|

| STEP 1 | Wegovy (semaglutide) | 2.4 mg | 14.9% | 68 weeks | 1,961 |

| STEP 3 | Wegovy (semaglutide) | 2.4 mg | 16.0% | 68 weeks | 611 |

| STEP 8 | Wegovy (semaglutide) | 2.4 mg | 15.8% | 68 weeks | 338 |

| SURMOUNT-1 | Mounjaro (tirzepatide) | 5 mg | 15.0% | 72 weeks | 2,539 |

| SURMOUNT-1 | Mounjaro (tirzepatide) | 10 mg | 19.5% | 72 weeks | 2,539 |

| SURMOUNT-1 | Mounjaro (tirzepatide) | 15 mg | 20.9% | 72 weeks | 2,539 |

The SURMOUNT-4 trial also showed that participants who stopped tirzepatide after 36 weeks regained a significant portion of their lost weight, which matches what is seen with semaglutide discontinuation in STEP 4. Both drugs work best when taken continuously (3).

What About Head-to-Head Data?

No large published trial has directly compared Wegovy and Mounjaro for weight loss in the same study at this time. The numbers above come from separate trial programs with slightly different populations, durations, and designs. Comparing across trials is useful but imperfect, but the trend is clear: tirzepatide at higher doses appears to produce greater average weight loss than semaglutide 2.4 mg.

Side Effects: Wegovy vs Mounjaro

Both medications share a similar side effect profile because they both act on GLP-1 receptors. Gastrointestinal issues are the most common complaints.

Most people experience some degree of nausea, especially during dose escalation. It usually improves over time, but for some people, side effects are significant enough to discontinue treatment.

Side Effects Comparison

| Side Effect | Wegovy (Semaglutide) | Mounjaro (Tirzepatide) |

|---|---|---|

| Nausea | 44% | 24–33% (dose dependent) |

| Diarrhea | 30% | 17–23% |

| Vomiting | 24% | 9–13% |

| Constipation | 24% | 17–20% |

| Abdominal pain | 20% | 14–18% |

| Headache | 14% | 12–14% |

| Fatigue | 11% | 9–12% |

| Injection site reactions | 3.2% | 3–7% |

| Gallbladder events | Uncommon | Uncommon |

| Pancreatitis | Rare | Rare |

Source: Prescribing information and clinical trial data for both medications (1, 2, 4).

Wegovy tends to cause more nausea and vomiting than Mounjaro, especially during the first few months. Both medications carry a boxed warning about medullary thyroid carcinoma risk based on animal studies, and neither should be used by individuals with a personal or family history of medullary thyroid cancer or Multiple Endocrine Neoplasia syndrome type 2.

For more details, read:

Serious Side Effects to Watch For

Both drugs carry warnings for:

  • Pancreatitis
  • Gallbladder disease
  • Kidney injury (primarily from dehydration due to vomiting/diarrhea)
  • Suicidal ideation (under ongoing investigation by Health Canada)
  • Thyroid C-cell tumours (in animal studies)

If you experience severe abdominal pain, persistent vomiting, or changes in mood, contact your healthcare provider right away.

Cost in Canada: Wegovy vs Mounjaro

Neither Wegovy nor Mounjaro is inexpensive without insurance, and provincial drug formulary coverage varies widely.

Cost Comparison

| Cost Factor | Wegovy | Mounjaro |

|---|---|---|

| Retail price (approx. monthly) | $350–$500 CAD | $350–$550 CAD |

| Annual cost without insurance | $4,200–$6,000 CAD | $4,200–$6,600 CAD |

| Manufacturer savings program | Yes (Novo Nordisk patient support) | Yes (Eli Lilly patient support) |

| Generic available | No | No |

| Compounded versions | Available through some clinics | Limited availability |

| Online pharmacy options | Yes | Yes |

Prices vary by pharmacy, province, and dose. Higher doses cost more. The numbers above reflect typical retail pricing at Canadian pharmacies as of early 2026.

For deeper breakdowns, see:

Insurance Coverage Comparison

| Coverage Factor | Wegovy | Mounjaro |

|---|---|---|

| Provincial formulary coverage | Limited (varies by province) | Limited (varies by province) |

| Private insurance | Growing coverage, often requires prior authorization | Newer to market, fewer plans cover it |

| Ontario (OHIP+/ODB) | Not covered for most patients | Not covered for most patients |

| British Columbia (PharmaCare) | Special Authority required | Special Authority required |

| Alberta (ADPP) | Limited coverage | Limited coverage |

| Quebec (RAMQ) | Conditional coverage | Under review |

| Employer benefit plans | Increasingly covered with documentation | Coverage growing but less established |

| Prior authorization | Almost always required | Almost always required |

Most Canadians will need to go through private insurance, provide documentation from their doctor, and possibly appeal a denial. Some provinces cover these medications more readily for type 2 diabetes than for weight management alone.

Generic Semaglutide at In-Person Canadian Pharmacies

Cash retail prices for generic semaglutide at Canadian pharmacies are now coming in below the telehealth alternatives, based on early Canadian consumer reports. Costco Pharmacy is the lowest reliable option at roughly $88 to $99 per month (confirmed pickups: $88.88 GTA, $88 Ontario, $99 Laval, $91 Medicine Hat). Walmart and Loblaws No Frills typically come in around $95 to $110 per month. Shoppers Drug Mart, Rexall and London Drugs are running roughly $100 to $120 per month (one Halifax-area Shoppers fill reported $113 for the 0.25mg starter dose). Apotex's Apo-Semaglutide Injection began shipping to Canadian pharmacies on May 20, 2026, with Dr. Reddy's generic also launching in May 2026.

That makes in-person pharmacies — especially Costco — meaningfully cheaper than telehealth providers for generic semaglutide. Felix Health and Hims Canada both list $149 per month all-in for the same generic Apo-Semaglutide on their public pricing pages. For most Canadians with a valid prescription, walking it into a local pharmacy is now the cheapest reliable path.

Pricing context: per the Globe and Mail, Apotex's published wholesale price is $78.14 for a four-week supply — roughly one-third of brand-name Ozempic's $240.48 wholesale price. Retail estimates above reflect that wholesale plus each chain's standard dispensing fee and markup. See also coverage from CBC News on the Canadian launch. Note: The May 2026 generic launch covers the Ozempic indication for type 2 diabetes only. Generic Wegovy (semaglutide 2.4 mg for chronic weight management) is not yet available — Novo Nordisk holds additional patents on the high-dose formulation. This generic launch is also not tirzepatide — generic Mounjaro is still years away as Eli Lilly's patents on tirzepatide extend through 2036+. Under the pan-Canadian Pharmaceutical Alliance framework, the maximum public drug plan price for generic semaglutide is approximately $114 per four-week supply with two manufacturers approved, dropping to roughly $80 once a third manufacturer launches.

Dosing Schedule and Dose Escalation

Both Wegovy and Mounjaro use gradual dose escalation to minimize side effects.

Wegovy dosing schedule:

  • Weeks 1–4: 0.25 mg weekly
  • Weeks 5–8: 0.5 mg weekly
  • Weeks 9–12: 1.0 mg weekly
  • Weeks 13–16: 1.7 mg weekly
  • Week 17 onward: 2.4 mg weekly (maintenance dose)

Mounjaro dosing schedule:

  • Weeks 1–4: 2.5 mg weekly
  • Weeks 5–8: 5 mg weekly
  • Then increase by 2.5 mg every 4 weeks as tolerated
  • Maximum dose: 15 mg weekly

Mounjaro offers more dosing flexibility. Your doctor can hold you at 5 mg, 7.5 mg, 10 mg, 12.5 mg, or 15 mg depending on response and side effects. Wegovy's target is a fixed 2.4 mg for most patients, though some may remain at lower doses.

Who Should Choose Which Drug?

The "better" drug depends on your health profile, budget, insurance, and how your body responds.

Patient Profile and Drug Selection

| Patient Profile | Better Option | Reason |