Mounjaro or Ozempic: Which Works Better for Weight Loss?

When it comes to losing weight, two medications are making waves: Mounjaro and Ozempic. Both were originally developed to help manage type 2 diabetes, but they’ve also been found to be effective for shedding pounds. With Mounjaro being the newer option and Ozempic having been around for a while, it can be tricky to decide which one is right for you. In this article, we'll explore how each one works, their side effects, and associated costs to help you decide which might be better for your weight loss journey.

What is Ozempic?

Ozempic is an Health Canada-approved medication for adults with Type 2 diabetes. Ozempic contains the active ingredient semaglutide. It helps lower blood sugar levels and manage weight. Ozempic also reduces the risk of major cardiovascular events.

How does Ozempic Work?

Ozempic works in several ways to help manage diabetes and improve overall health:

  1. Stimulates Insulin Secretion: When you eat, your blood sugar rises. Ozempic triggers your pancreas to release insulin, which helps lower blood sugar.
  2. Reduces Glucagon Levels: Glucagon is a hormone that raises blood sugar. Ozempic reduces glucagon levels, keeping blood sugar more stable.
  3. Delays Gastric Emptying: Ozempic slows down how quickly food leaves your stomach. This makes you feel full longer and can help reduce how much you eat.
  4. Lowers Blood Glucose Levels: By stimulating insulin and reducing glucagon, Ozempic helps keep your blood sugar within a healthy range.

What is Mounjaro?

Mounjaro, like Ozempic, is an Health Canada-approved medication for managing Type 2 diabetes. However, it contains a different active ingredient called tirzepatide. Mounjaro has shown higher effectiveness in controlling blood sugar and aiding in weight loss compared to Ozempic. Despite its benefits, it tends to be more expensive and may come with additional side effects.

How does Mounjaro Work?

Mounjaro operates through unique mechanisms that set it apart from other diabetes medications:

  1. Dual GIP and GLP-1 Receptor Agonist: Unlike Ozempic, which targets only GLP-1 receptors, Mounjaro acts on both GIP and GLP-1 receptors. This dual action enhances its effectiveness.
  2. Suppresses Glucagon and Enhances Insulin Secretion: Mounjaro reduces the levels of glucagon, which raises blood sugar, and boosts insulin secretion to lower blood sugar levels more effectively.
  3. Offers Comprehensive Diabetes Management: By targeting two different pathways, Mounjaro provides a more thorough approach to controlling blood sugar levels. This makes it a robust option for diabetes management.
  4. Potential for More Significant Weight Loss: Clinical studies indicate that Mounjaro users often experience more substantial weight loss compared to those using Ozempic. This is partly because its dual receptor action can better control appetite and food intake.

Mounjaro's advanced mechanisms make it a powerful tool for those managing Type 2 diabetes, although its higher cost and potential for more severe side effects should be considered.

How Effective are Ozempic and Mounjaro?

When comparing Ozempic vs. Mounjaro, multiple studies highlight that Mounjaro excels in both weight loss and blood sugar control. While Ozempic is effective, particularly in reducing A1C levels and cardiovascular risks, Mounjaro often achieves even better outcomes.

Comparison of Clinical Trials

Clinical trials provide a clear comparison between the effectiveness of these two medications:

Phase 3 SURPASS-2 Study

The Phase 3 SURPASS-2 study compared Mounjaro (tirzepatide) with Ozempic (semaglutide) over 40 weeks. The study focused on adults with type 2 diabetes whose blood sugar levels were not controlled by metformin alone. Participants had an average starting A1C of 8.3% and a weight of about 207 pounds.

  • A1C Reduction Results:
    • Mounjaro 5 mg, 10 mg, and 15 mg injections lowered A1C by 2.0% to 2.3%.
    • Ozempic 1 mg injections reduced A1C by 1.9%.
  • Weight Loss Results:
    • Participants on Mounjaro lost between 17 to 25 pounds.
    • Those on Ozempic lost about 13 pounds.

Meta-analysis: EASD Abstract

A meta-analysis presented at the European Association for the Study of Diabetes (EASD) meeting compared tirzepatide (Mounjaro) and semaglutide (Ozempic) across 22 randomized controlled trials involving 18,472 participants.

  • Effectiveness Comparison:
    • Tirzepatide 15 mg was the most effective in lowering A1C, followed by tirzepatide 10 mg, and then semaglutide 2 mg.
    • Each tirzepatide dose reduced A1C more than the respective semaglutide doses.
  • A1C and Weight Loss Outcomes:
    • Tirzepatide 10 mg and 15 mg doses were more effective in lowering body weight than semaglutide 1 mg and 2 mg doses.
    • Tirzepatide 5 mg was more effective than semaglutide 0.5 mg and 1 mg.
  • Side Effect Profiles:
    • Gastrointestinal side effects were common with both drugs.
    • Tirzepatide had a higher risk for nausea, vomiting, and diarrhea at higher doses.

Why Consider Mounjaro for Weight Loss?

Greater Weight Loss in Clinical Trials Compared to Ozempic

Mounjaro has shown more significant weight loss results in clinical trials than Ozempic. In the SURPASS-2 study, participants taking Mounjaro lost between 17 to 25 pounds, while those on Ozempic lost about 13 pounds. This difference can be crucial if substantial weight loss is your primary goal.

Dual-Action Mechanism Benefits

Mounjaro works on both GIP (glucose-dependent insulinotropic polypeptide) and GLP-1 (glucagon-like peptide-1) receptors. This dual-action mechanism helps reduce blood sugar levels more effectively and leads to greater weight loss.

  • GIP and GLP-1:
    • GIP: Lowers blood sugar by stimulating insulin release.
    • GLP-1: Slows down digestion, making you feel fuller longer and eat less.

Having both mechanisms in one medication can lead to better overall results in managing weight and blood sugar levels.

Potential for Better Long-Term Weight Management

Mounjaro's dual-action mechanism not only helps with immediate weight loss but may also offer better long-term weight management. The combined effects of GIP and GLP-1 can help you maintain your weight loss by:

  • Reducing Food Intake: Making you feel full faster and longer.
  • Lowering Blood Sugar: Helping control cravings and overeating.

Why Consider Ozempic for Weight Loss?

Proven Cardiovascular Benefits

Ozempic stands out because of its proven cardiovascular benefits. It is approved to lower the risk of major cardiovascular events, such as heart attacks and strokes, in adults with type 2 diabetes. This makes it a good option if you have diabetes and are worried about heart health.

  • Cardiovascular Outcomes:
    • Heart Attack Reduction: Studies show a significant decrease in heart attacks among Ozempic users.
    • Stroke Prevention: Reduces the risk of strokes, adding another layer of protection for your heart.

Established Safety Profile

Ozempic has a well-established safety profile. It has been on the market longer than Mounjaro, allowing for a more comprehensive understanding of its effects and side effects over time.

  • Health Canada Approvals: Ozempic has undergone rigorous testing and received Health Canada approval for multiple uses, including cardiovascular risk reduction.
  • Long-Term Data: More long-term data are available, providing reassurance about its safety and effectiveness.

Effective in Lowering A1C Levels

Ozempic is highly effective at lowering A1C levels, which measure long-term blood sugar control. This can be particularly beneficial if you have type 2 diabetes.

  • A1C Reduction:
    • 0.5 mg Dose: Lowers A1C by about 1.1% on average.
    • 1 mg Dose: Lowers A1C by about 1.5% on average.
    • 2 mg Dose: Lowers A1C by about 1.8% on average.

Lowering your A1C can help prevent diabetes complications like nerve damage, heart disease, and kidney problems.

Are There Any Risks or Side Effects to Be Aware Of?

Common Gastrointestinal Side Effects for Both Drugs

Both Mounjaro and Ozempic can cause gastrointestinal (GI) issues. These side effects are the most common and usually occur when you first start the medication or increase the dose.


  • Mounjaro: 12% to 18% of users.
  • Ozempic: 16% to 20% of users.


  • Mounjaro: 12% to 17% of users.
  • Ozempic: 8.5% to 8.8% of users.


  • Mounjaro: 5% to 9% of users.
  • Ozempic: 5% to 9.2% of users.


  • Mounjaro: 6% to 7% of users.
  • Ozempic: 3.1% to 5% of users.

Management Tips:

  • Slow Dose Increase: Gradually increasing the dose can help minimize these side effects.
  • Stay Hydrated: Drinking plenty of water can help alleviate symptoms like constipation and diarrhea.
  • Small, Frequent Meals: Eating smaller meals more often can reduce nausea and vomiting.

Serious Side Effects and Health Canada Warnings

Both medications come with serious side effects that you should be aware of. These are less common but important to monitor.

Thyroid Tumors:

  • Boxed Warning: Both Mounjaro and Ozempic carry a boxed warning for potential thyroid tumors, including cancer, observed in animal studies.
  • Do Not Use If: You or your family have a history of medullary thyroid carcinoma (MTC) or Multiple Endocrine Neoplasia syndrome type 2 (MEN 2).

Symptoms to Watch For:

  • Neck Mass: Any swelling or lump in the neck.
  • Trouble Swallowing: Difficulty swallowing food or liquids.
  • Shortness of Breath: Unexplained breathing issues.
  • Persistent Hoarseness: Changes in your voice that don't go away.

Other Serious Side Effects:

  • Pancreatitis: Inflammation of the pancreas, causing severe stomach pain.
  • Gallbladder Disease: Issues like gallstones can occur, leading to abdominal pain and digestive problems.

How to Handle Potential Thyroid Tumor Risks

If you have a personal or family history of thyroid issues, consult your healthcare provider before starting either medication.

Preventive Measures:

  • Regular Check-ups: Schedule regular visits with your doctor to monitor for any signs of thyroid changes.
  • Blood Tests: Routine blood tests can help catch any abnormalities early.
  • Ultrasounds: Imaging tests like ultrasounds can help detect thyroid changes.

Recent Updates on Side Effects Like Ileus

Health Canada recently updated the list of side effects for both Mounjaro and Ozempic to include ileus, an intestinal blockage that doesn't involve a physical obstruction.

Symptoms of Ileus:

  • Abdominal Swelling: Noticeable bloating or swelling in the stomach area.
  • Fullness and Gas: Feeling unusually full or gassy.
  • Stomach Pain: Cramping or pain in the abdominal area.
  • Breath Odor: Unusual odor from your breath.
  • Constipation: Severe constipation or inability to pass gas.
  • Vomiting: Occasional vomiting.

Management Tips:

  • Immediate Medical Attention: If you experience these symptoms, seek medical help right away.
  • Discuss Risks with Doctor: Talk to your healthcare provider about your risk for ileus and ways to mitigate it.

Cost & Insurance Coverage

Average monthly costs without insurance: Ozempic and Mounjaro come with significant price tags. Without insurance, a monthly supply of Ozempic costs around $220 to $265. Mounjaro, on the other hand, is even more expensive, with a monthly cost of approximately $380 to $480. These prices can vary slightly depending on the pharmacy and location. We usually recommend Costco Pharmacy as they usually have some of the best pricing.

Insurance coverage variations: Insurance coverage can significantly affect your out-of-pocket expenses. While provincial insurances such as OHIP in Canada do not generally cover the cost of either Ozempic nor Mounjaro for weight loss, some private insurances such as those offered through employers may.

What Works Better: Mounjaro or Ozempic for Weight Loss?

Real-World Study by Truveta:

  • Weight Loss Achievements:
    • Tirzepatide users were 1.8 times more likely to achieve 5% weight loss.
    • 2.4 times more likely to achieve 10% weight loss.
    • Three times more likely to achieve 15% weight loss compared to semaglutide users.
  • Timeframe:
    • 3 Months: Average weight loss of 5.9% for tirzepatide users vs. 3.6% for semaglutide users.
    • 6 Months: Average weight loss of 10.1% for tirzepatide users vs. 5.9% for semaglutide users.
    • 1 Year: Average weight loss of 15.2% for tirzepatide users vs. 7.9% for semaglutide users.

Factors Influencing Drug Choice

Choosing between Mounjaro and Ozempic depends on various factors.

Side Effects:

  • Mounjaro: Higher rates of nausea, vomiting, and diarrhea but more effective for weight loss.
  • Ozempic: Fewer gastrointestinal side effects but less effective for weight loss.


  • Mounjaro: Approximately $380 - $480 per month
  • Ozempic: Around $220 - $265 per month

Expert Opinions and Recommendations

Experts weigh in based on clinical data and patient outcomes.

Nick Stucky, MD, PhD:

  • Emphasizes the importance of real-world data.
  • Notes that GLP-1 medications have revolutionized treatment for type 2 diabetes and obesity.

Tyler Gluckman, MD, MHA:

  • Highlights the need for timely data to inform patient care.
  • Stresses the importance of understanding real-world effectiveness beyond clinical trials.

Patients should also explore other GLP-1 agonists like Saxenda, Rybelsus, and Wegovy, which might offer different benefits or be more cost-effective based on their insurance plans. Consulting with a healthcare provider can help determine the most suitable and affordable option tailored to individual health needs and insurance coverage.

Disclaimer: This blog post is intended for educational purposes only and should not be taken as medical advice. Always consult your healthcare provider for personal health concerns.