Wegovy (semaglutide) and Mounjaro (tirzepatide) are weekly injectable medications that target appetite and metabolism, but they differ in ingredients, FDA approval status, and how much weight loss you can expect. This guide offers a clear, side-by-side comparison to help you discuss these two GLP-1-based options with your healthcare provider.

What’s the Main Difference Between Wegovy and Mounjaro?

In the rapidly evolving landscape of weight management medications, Wegovy and Mounjaro have emerged as two of the most prominent and effective options. While both are once-weekly injectable drugs that aid in significant weight loss, the main difference between them lies in their mechanism of action, which in turn influences their efficacy and approved uses. Wegovy acts on a single hormone pathway (GLP-1), while Mounjaro targets two (GLP-1 and GIP), which may explain differences in effectiveness.

Wegovy (semaglutide)

• Drug class: GLP-1 receptor agonist
• FDA-approved indications: Chronic weight management in adults and children 12+ with obesity or overweight and at least one weight-related condition; to reduce the risk of major cardiovascular events in adults with heart disease and either obesity or overweight
• Mechanism of action: Works by mimicking the GLP-1 hormone, which helps regulate appetite and calorie intake

Mounjaro (tirzepatide)

• Drug class: Dual GLP-1 and GIP receptor agonist
• FDA-approved indication: Type 2 diabetes; may be used off-label for weight loss
• Mechanism of action: Activates both GLP-1 and GIP receptors, potentially amplifying appetite suppression and metabolic benefits

Is Mounjaro More Effective Than Wegovy for Weight Loss?

Head-to-head trials and major studies show Mounjaro generally leads to greater weight loss than Wegovy:

• In the SURMOUNT-1 trial, participants with obesity taking tirzepatide lost about 21% of their body weight over 72 weeks.
• In STEP trials, the average weight loss with Wegovy was about 15% at the standard 2.4 mg dose over 68–72 weeks.
• A recent direct comparison found tirzepatide users lost about 15% of their weight, compared to 8% for semaglutide users after 1 year.

While Mounjaro appears more effective for weight loss on average, it is important to note that individual results can vary widely.

What Are the Side Effects of Wegovy vs Mounjaro?

When considering prescription medications for weight loss, understanding the potential side effects is a critical part of the decision-making process. Wegovy and Mounjaro come with a similar, yet distinct, side effect profile.

The most common side effects for both medications are gastrointestinal in nature, and include:

• Nausea
• Constipation
• Diarrhea
• Vomiting
• Fatigue
• Burping
• Poor appetite

In a recent head-to-head trial, the incidence of these side effects was similar among both medications. Gastrointestinal side effects are mild to moderate and mostly occur when the dose is raised up to the maintenance dose.

Other side effects reported by patients taking Wegovy or Mounjaro include stomach pain, headache, hair loss, indigestion, dizziness, and injection site reactions.

Both medications carry a "boxed warning" from the U.S. Food and Drug Administration (FDA) regarding the risk of thyroid C-cell tumors. This is the most serious type of warning issued by the FDA, intended to highlight potentially life-threatening risks associated with a medication. The warning is based on studies in which both drugs caused thyroid C-cell tumors in rodents. While it is currently unknown whether Mounjaro and Wegovy cause these tumors in humans, the potential risk has prompted the stringent warning.

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Which Costs More, Wegovy or Mounjaro?

While Mounjaro typically boasts a lower list price than Wegovy, the final cost for patients can fluctuate significantly based on insurance coverage, available savings programs, and the pharmacy they use. As of mid-2025, the list price for a one-month supply of Wegovy is approximately $1,349 (or $499 when supplied from Novo Nordisk’s NovoCare Pharmacy), whereas Mounjaro's list price is around $1,163. These prices are based on the Drugs.com Price Guides for Mounjaro and Wegovy using the Drugs.com discount card.

Both manufacturers offer savings programs for eligible patients with commercial insurance. With these copay cards, patients may pay as little as $0-$25 for their medication. Insurance approval may be based on the FDA label, so while Mounjaro is sometimes used off-label for weight loss the insurance may not cover it for this unapproved indication.

Medication	List Price (Monthly)	Savings Card (With Insurance)	Notes
Wegovy	~$1,349	As low as $0	FDA-approved for weight loss; insurance more likely to cover for this use
Mounjaro	~$1,163	As low as $25	FDA-approved for diabetes; insurance may not cover for weight loss

Can You Switch from Wegovy to Mounjaro?

Yes, it is possible to switch from Wegovy to Mounjaro under the supervision of a healthcare provider.

Switching may be considered if:

• Wegovy is not effective enough
• Side effects are problematic
• There are supply shortages

How to Switch:

• Consult your healthcare provider for a personalized plan.
• You may need to taper off Wegovy and wait several weeks before starting Mounjaro.
• Start Mounjaro at the lowest dose, monitoring for side effects.

Mounjaro for weight loss is an off-label use, so insurance coverage may be limited.

Is Mounjaro FDA-Approved for Weight Loss Like Wegovy?

Mounjaro is FDA approved for type 2 diabetes, but another brand called Zepbound that contains the same active ingredient (semaglutide) is FDA approved for weight loss like Wegovy. However, Mounjaro may be prescribed off-label for weight loss.

Summary

Both Wegovy and Mounjaro have demonstrated significant weight loss benefits, but they differ in effectiveness, approval status, and cost. Mounjaro tends to result in greater average weight loss, but it is only FDA-approved for diabetes (unless prescribed as Zepbound for weight loss). Side effects and insurance coverage should be considered. Always discuss your options and medical history with a healthcare provider to determine the best approach for your weight management goals.

This is not all the information you need to know about Mounjaro or Wegovy for safe and effective use and does not take the place of your doctor’s directions. Review the full patient medication guide and discuss this information and any questions you have with your doctor or other health care provider.

References

1. Aronne, L. J., Horn, D. B., le Roux, C. W., Ho, W., Falcon, B. L., Gomez Valderas, E., Das, S., Lee, C. J., Glass, L. C., Senyucel, C., Dunn, J. P., & SURMOUNT-5 Trial Investigators (2025). Tirzepatide as Compared with Semaglutide for the Treatment of Obesity. The New England journal of medicine, 10.1056/NEJMoa2416394. Advance online publication. https://doi.org/10.1056/NEJMoa2416394
2. Jastreboff, A. M., Aronne, L. J., Ahmad, N. N., Wharton, S., Connery, L., Alves, B., Kiyosue, A., Zhang, S., Liu, B., Bunck, M. C., Stefanski, A., & SURMOUNT-1 Investigators (2022). Tirzepatide Once Weekly for the Treatment of Obesity. The New England journal of medicine, 387(3), 205–216. https://doi.org/10.1056/NEJMoa2206038
3. Mounjaro [package insert]. Updated 2025. Eli Lilly and Company. Accessed on June 11, 2025 at https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=d2d7da5d-ad07-4228-955f-cf7e355c8cc0
4. Rodriguez, P. J., Goodwin Cartwright, B. M., Gratzl, S., Brar, R., Baker, C., Gluckman, T. J., & Stucky, N. L. (2024). Semaglutide vs Tirzepatide for Weight Loss in Adults With Overweight or Obesity. JAMA internal medicine, 184(9), 1056–1064. https://doi.org/10.1001/jamainternmed.2024.2525
5. Singh, G., Krauthamer, M., & Bjalme-Evans, M. (2022). Wegovy (semaglutide): a new weight loss drug for chronic weight management. Journal of investigative medicine : the official publication of the American Federation for Clinical Research, 70(1), 5–13. https://doi.org/10.1136/jim-2021-001952
6. Wegovy [package insert]. Updated 2024. Novo Nordisk. Accessed on June 11, 2025 at https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=ee06186f-2aa3-4990-a760-757579d8f77b

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