Mounjaro (Tirzepatide) and Wegovy (Semaglutide) have garnered significant attention since their introduction to the market. One standout characteristic that has contributed to their popularity is the substantial weight loss experienced by individuals using these medications.

While both Mounjaro and Wegovy are injectable drugs with numerous similarities, there are notable distinctions between them, particularly regarding their FDA-approved applications, active ingredients, and eligibility criteria. This article will shed more light on these key similarities and differences.

Key Facts

  • Wegovy and Mounjaro are two liquid medications injected subcutaneously once weekly.
  • The active ingredient in Wegovy is Semaglutide, while Mounjaro's is Tirzepatide.
  • They are both effective for weight loss and blood sugar control. However, Wegovy has been FDA-approved only for weight loss, and Mounjaro is only approved for blood sugar management related to type 2 diabetes.
  • While Mounjaro and Wegovy are GLP-1 receptor agonists, Mounjaro has a dual mechanism and is also a glucose-dependent insulinotropic polypeptide (GIP) mimetic.

Similarities and Differences Between Mounjaro and Wegovy

Below are the similarities and differences between Wegovy and Mounjaro regarding their FDA-approved uses, doses, side effects, efficacy, working mechanisms, and cost.

Approved Usage: What Wegovy is Used for vs. What Mounjaro is Used for?

Wegovy is FDA-approved for long-term weight management in individuals with obesity or those who are overweight with specific weight-related conditions, such as high blood pressure. In contrast, Mounjaro is not FDA-approved for weight-related conditions but can be prescribed off-label for such purposes. Mounjaro is instead FDA-approved for managing blood sugar levels in adults with type 2 diabetes.

However, it's important to note that Wegovy and Mounjaro are not magic pills for weight loss. Both are prescribed as part of a comprehensive strategy, including healthy diets and exercise, to aid weight management.

Working Mechanism: How Wegovy Works vs. How Mounjaro Works

Mounjaro and Wegovy are both GLP-1 receptor agonists that aid weight loss and enhance blood glucose control. GLP-1 receptor agonists mimic the actions of the GLP-1 hormones by triggering insulin release and delaying gastric emptying. They also communicate with the hypothalamus (the brain's appetite control center) to lower food cravings.

The only difference between Wegovy and Mounjaro in terms of working mechanism is that apart from being a GLP-1 receptor agonist, Mounjaro also acts as a glucose-dependent insulinotropic polypeptide (GIP) mimetic. GIP is a hormone supporting blood glucose levels and facilitating the storage of excess energy in fat cells. Consequently, Mounjaro uniquely mimics two essential hormones, contributing to its dual functionality in promoting weight loss and blood glucose regulation.

Eligibility: Who is Eligible for Wegovy vs. Who is Eligible for Mounjaro

To be eligible for Wegovy, you must be an adult with a BMI of 30 or higher or a BMI of at least 27 with weight-related health conditions. Adolescents aged 12 and older with a BMI at or above the 95th percentile for their age and sex are also eligible for Wegovy.

Mounjaro, on the other hand, is prescribed for adults with Type 2 diabetes without a specific BMI requirement.

Dosing and Administration: Dosage for Wegovy vs. Mounjaro

The Wegovy dosage for weight management slightly differs from that of Mounjaro for type 2 diabetes.

Here are the recommended doses for Wegovy and Mounjaro for weight management and type 2 diabetes, respectively:

Wegovy (for weight management):

Forms: Prefilled single-dose injection pens.

Frequency: Once per week

Administration: Self-administered subcutaneously into the upper arm, abdomen, or thigh.

Strengths: 0.25 mg/0.5 mL, 0.5 mg/0.5 mL, 1 mg/0.5 mL, 1.7 mg/0.75 mL, 2.4 mg/0.75 mL.

Dose progression:

  • Weeks 1–4: 0.25 mg
  • Weeks 5–8: 0.5 mg
  • Weeks 9–12: 1 mg
  • Weeks 13–16: 1.7 mg
  • Week 17 onwards: 2.4 mg

Mounjaro for type 2 diabetes (and off-label for weight management):

Forms: Prefilled single-dose injection pens.

Frequency: Once per week

Administration: Self-administered subcutaneously into the upper arm, abdomen, or thigh.

Strengths: 2.5 mg/0.5 mL, 5 mg/0.5 mL, 7.5 mg/0.5 mL, 10 mg/0.5 mL, 12.5 mg/0.5 mL, 15 mg/0.5 mL

Dose progression:

  • Weeks 1–4: 2.5 mg
  • Weeks 5–8: 5 mg
  • Week 9 onwards: Your doctor may increase your dose by 2.5 mg every 4 weeks, up to a maximum of 15 mg, if necessary.

NOTE: The dosage instructions above shouldn't replace personalized medical advice. Your doctor is best positioned to assess your specific condition and provide instructions on properly administering Wegovy or Mounjaro.

Side Effects: What are the side effects of Wegovy and Mounjaro?

Wegovy and Mounjaro cause side effects ranging from minor to severe. Let's compare both medications based on the most reported side effects.

Minor Side Effects:

  • Wegovy: Gastrointestinal side effects like diarrhea, nausea, constipation, and indigestion; dizziness, fatigue (low energy), hair loss, headache, stomach flu, common cold, mild increases in heart rate, and injection site reactions, such as swelling and itching around the injection area.
  • Mounjaro: Gastrointestinal side effects, such as diarrhea, nausea, constipation, and indigestion; Injection site reactions like swelling and itching around the injection area; Mild increases in heart rate.

Severe Side Effects

  • Wegovy: Hypoglycemia (low blood sugar), pancreatitis (swelling of the pancreas), cholecystitis (swelling of the gallbladder), gallstones, allergic reactions, and risk of thyroid cancer.
  • Mounjaro: Hypoglycemia, pancreatitis, cholecystitis, gallstones, severe digestive problems (including severe diarrhea), risk of thyroid cancer, and allergic reactions.

Effectiveness: How effective are Wegovy and Mounjaro?

Clinical studies on Wegovy and Mounjaro have shown that both drugs are effective for their approved purposes: Wegovy is effective for weight management, and Mounjaro benefits people with type 2 diabetes. However, research on Mounjaro's application in managing type 2 diabetes also showed it positively impacts weight loss. And obese people with insulin resistance lose weight and improve their insulin sensitivity while on Wegovy. However, it's noteworthy that individual results with Wegovy or Mounjaro may vary. So, you must discuss with your doctor to determine the suitability of these drugs for your specific situation.

Studies on Wegovy and Mounjaro for Weight Loss:

While Wegovy and Monjaro haven't been directly compared for weight loss in clinical trials, the weight loss effects of both drugs in people with type 2 diabetes have been evaluated in a review . The review suggests that the highest Mounjaro dosage (15mg once weekly) yields more weight loss than Wegovy, taken at the maximum dose of 2.4mg weekly.

Another review, focusing on individuals without diabetes, also concluded that Mounjaro (at a dose of 10 mg or 15 mg per week) was more effective for weight loss than Wegovy (at a dose of 2.4 mg per week).

Notably, the dosage of Mounjaro plays a crucial role in these outcomes, with its higher doses associated with more weight loss.

The Cost of Wegovy vs. The Cost of Mounjaro

The cost of initiating your weight loss journey (with Wegovy) or your type 2 diabetes management (with Mounjaro) depends on your treatment plan, insurance coverage, and pharmacy. However, Wegovy generally costs around $1,430 per month, while the price for Mounjaro is about $1,087 for a month's supply. 

Mounjaro and Wegovy offer various deals, including printable coupons, rebates, savings cards, trial offers, or free samples. Some of these offers can be printed online, while others may require registration or consultation with a medical professional.

Frequently Asked Questions

Can I switch between Wegovy and Mounjaro?

It's possible to switch from Wegovy to Mounjaro and vice versa, depending on your health condition. But note that Mounjaro for weight loss is considered an off-label use since it is only approved for type 2 diabetes treatment.

For individuals with Type 2 diabetes and a BMI of 27 or higher, both Wegovy and Mounjaro are options and can be switched if your doctor recommends that.

NOTE: Whether switching from Wegovy to Mounjaro or Mounjaro to Wegovy, it's pertinent to do so under a doctor's supervision.

Can you take Wegovy and Mounjaro together?

No. Mounjaro and Wegovy can not be taken together. Tirzepatide and Semaglutide (the active ingredients in Mounjaro and Wegovy, respectively) are both GLP-1 agonists and will likely cause severe unwanted side effects when taken together.

Conclusion

The comparison between Wegovy and Mounjaro reveals distinctive features and considerations for individuals seeking diabetic and chronic weight management. Both medications, while not directly compared in clinical trials, have demonstrated significant efficacy in promoting weight loss and managing blood sugar levels, with Mounjaro exhibiting notable effectiveness, given its higher doses.

The choice between Wegovy and Mounjaro depends on various factors, including the individual's specific health condition and their response to treatment. Patients must discuss openly with their healthcare providers to determine the most suitable option for their unique needs and health goals. As the field of weight and diabetes management continues to evolve, ongoing research and future developments may further inform the decision-making process, emphasizing the importance of staying informed and maintaining a collaborative approach to healthcare decisions.

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About the Author

Ely Fornoville

Hi, I'm Ely Fornoville, and I am the founder of Diabetic Me. Being a type 1 diabetic since 1996, I developed a passion to help people learn more about diabetes. I write about diabetes and share stories from other diabetics around the world. I currently use a Medtronic Guardian 4 CGM and a MiniMed 780G insulin pump with Humalog insulin.

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