Mounjaro vs Zepbound: Differences, Uses, Side Effects & More

Introduction

Mounjaro and Zepbound are two injectable medications that have gained attention for their roles in managing chronic health conditions. While both contain the same active ingredient, tirzepatide, they are FDA-approved for different uses: Mounjaro is approved for the treatment of type 2 diabetes (T2DM), whereas Zepbound is approved for chronic weight management in adults with obesity or overweight (with at least one weight-related condition)^1,2. 

People often compare Mounjaro and Zepbound because they share the same mechanism of action but are marketed for different health conditions. Through this article, we aim to understand the differences between Zepbound vs Mounjaro better, their effectiveness, dosing, side effects, and suitability for different health goals. 

Zepbound vs Mounjaro

While Zepbound and Mounjaro share the same active ingredient, their approved uses and practical applications differ. Below is a side-by-side look at how they compare across key metrics^3,5: 

How Do Zepbound and Mounjaro Work?

Both Zepbound and Mounjaro contain tirzepatide, a unique medication that works through dual incretin receptor agonism, targeting both GLP-1 (glucagon-like peptide-1) and GIP (glucose-dependent insulinotropic polypeptide) receptors⁶. This dual action sets tirzepatide apart from older treatment options that target GLP-1 alone. 

GLP-1 Mechanism: GLP-1 is a hormone released in the gut after eating. Tirzepatide enhances GLP-1 activity, which^6,7: 

• Increases insulin secretion (only when glucose levels are high) 
• Decreases glucagon release (a hormone that raises blood sugar) 
• Slows down gastric emptying (keeping you full longer) 

GIP Mechanism: GIP is another gut hormone that helps regulate insulin and fat metabolism. Tirzepatide mimics GIP to^6,7: 

• Further, boost insulin secretion in response to food 
• Improve the body’s sensitivity to insulin 
• Potentially support better fat metabolism 

The combination of GLP-1 and GIP receptor activity makes Tirzepatide highly effective in both formulations by: 

• Lowering blood glucose levels (in Mounjaro, for T2DM) 
• Promoting significant weight management (in Zepbound, for obesity and overweight management) 

FDA-Approved Uses and Dosing

Mounjaro was approved by the FDA in May 2022 for the treatment of T2DM in adults, to be used alongside diet and exercise³. 

Zepbound, approved in November 2023, is indicated for chronic weight management in adults with obesity or those who are overweight and have at least one weight-related health condition (such as hypertension)⁴. 

Regarding Mounjaro vs Zepbound dosing, both follow a once-weekly injection schedule (starting at 2.5 mg), with gradual dose increases based on individual response and tolerance^3,4. 

Which Conditions Do They Help Manage?

Both medications have different treatment goals despite having the same active ingredient: 

• Mounjaro: Its goal is to help improve blood sugar control by mimicking the natural hormones involved in glucose regulation³. In a 40-week study involving 475 adults with T2DM, tirzepatide significantly reduced HbA1c (a measure of average blood glucose levels) by up to 2.4%⁸. 
• Zepbound: It’s designed to support long-term weight management efforts when combined with a reduced-calorie diet and increased physical activity. This may reduce the risk of serious health issues like cardiovascular diseases⁴. In a 72-week study involving 938 adults with obesity or overweight, tirzepatide led to up to 14.7% body weight reduction⁹. 

Note: In the comparison of Zepbound vs Mounjaro for weight loss, both contain tirzepatide, but Zepbound is approved specifically for weight management. 

While the approved indications differ, both drugs offer metabolic benefits that help address modern health challenges like obesity and diabetes.  

Side Effects: Zepbound vs Mounjaro Safety Comparison

Looking at Zepbound vs Mounjaro side effects, both share a similar safety profile. Most side effects are related to the gastrointestinal system and tend to be mild to moderate, especially during the early weeks of treatment. However, like all medications, serious side effects are possible and should be monitored. 

Here’s a side-by-side comparison of the common and serious side effects reported for both Zepbound and Mounjaro^3,4: 

Important Safety Note: Both medications carry a boxed warning about the potential risk of thyroid C-cell tumours, although this has only been observed in animal studies. Neither Zepbound nor Mounjaro is recommended for individuals with a personal or family history of medullary thyroid carcinoma (MTC) or multiple endocrine neoplasia syndrome type 2 (MEN 2)^3,4. 

Cost and Availability: India and Global

Mounjaro is available in India via prescription, with costing typically starting from three thousand five hundred rupees for one dose. Zepbound has not been officially launched in India yet.  

Globally, both drugs are available (primarily in the U.S. and other developed countries), with prices differing based on dosage and insurance coverage. 

Note: Always consult a doctor before starting either medication. The availability, suitability, and cost of a drug can vary based on your health condition, location, and access to insurance or patient assistance programs. 

Are Zepbound and Mounjaro Interchangeable?

Zepbound and Mounjaro contain the same active ingredient, tirzepatide, and work through the same dual hormone mechanism (GLP-1 and GIP receptor agonism). However, they are not officially interchangeable, as they are FDA-approved for different medical conditions: 

• Mounjaro is approved for T2DM³. 
• Zepbound is approved for chronic weight management⁴. 

Therefore, switching should not be done without medical guidance. A doctor will assess your condition, treatment goals, and possible side effects to determine the most appropriate option. Self-switching is not advised due to regulatory and therapeutic considerations. 

Conclusion

The primary Mounjaro vs Zepbound difference lies in their approved use: Mounjaro has been approved for T2DM, while Zepbound has been approved for chronic weight management. Their dosing, side effects, and mechanisms are similar, but their FDA approvals, insurance coverage, and clinical use cases differ. 

Ultimately, the right choice of medicine depends on individual health needs, including whether the focus is on blood sugar control, weight management, or both. Factors like medical history, current medications, cost, and availability also play a role in choosing the medicine. Therefore, always consult your doctor to determine which option is the safest and most effective for your specific condition. They can guide you through the risks, benefits, and practical considerations before starting treatment. 

Also Read: Mounjaro (Injection): Uses, Side Effects, Dosage, and How It Works 

Frequently Asked Questions (FAQs)

References

1. U.S. Food and Drug Administration. Drug Trials Snapshots: MOUNJARO. U.S. Department of Health and Human Services. [cited 2025 Jun 16]. Available from: https://www.fda.gov/drugs/drug-approvals-and-databases/drug-trials-snapshots-mounjaro 
2. U.S. Food and Drug Administration. FDA approves new medication for chronic weight management. FDA. 2023; [cited 2025 Jun 16]. Available from: https://www.fda.gov/news-events/press-announcements/fda-approves-new-medication-chronic-weight-management 
3. U.S. Food and Drug Administration. Mounjaro (tirzepatide) injection, for subcutaneous use: Highlights of prescribing information. FDA. 2022; [cited 2025 Jun 09]. Available from: https://www.accessdata.fda.gov/drugsatfda_docs/label/2022/215866s000lbl.pdf 
4. U.S. Food and Drug Administration. ZEPBOUND™ (tirzepatide) Injection, for subcutaneous use: Highlights of prescribing information. FDA. 2023; [cited 2025 Jun 09]. Available from: https://www.accessdata.fda.gov/drugsatfda_docs/label/2023/217806s000lbl.pdf 
5. Central Drugs Standard Control Organisation (CDSCO). Recommendations of the Subject Expert Committee (Endocrinology & Metabolism) meeting held on 13 August 2024 [Internet]. New Delhi: CDSCO; 2024 Aug 13 [cited 2025 Jun 17]. Available from: https://cdsco.gov.in/opencms/resources/UploadCDSCOWeb/2018/UploadCommitteeFiles/Recommendations%20Endocrinology%20%26%20Metabolism%2013.08.2024.pdf 
6. Seino Y, Fukushima M, Yabe D. GIP and GLP-1, the two incretin hormones: Similarities and differences. J Diabetes Investig. 2010 Apr 22;1(1-2):8-23. Available from: https://pmc.ncbi.nlm.nih.gov/articles/PMC4020673/ 
7. Farzam K, Patel P. Tirzepatide [Internet]. StatPearls Publishing. 2025; [cited 2025 Jun 09]. Available from: https://www.ncbi.nlm.nih.gov/books/NBK585056/ 
8. Dahl D, Onishi Y, Norwood P, Huh R, Bray R, Patel H, Rodríguez Á. Effect of Subcutaneous Tirzepatide vs Placebo Added to Titrated Insulin Glargine on Glycemic Control in Patients With Type 2 Diabetes: The SURPASS-5 Randomized Clinical Trial. JAMA. 2022 Feb 8;327(6):534-545. Available from: https://pubmed.ncbi.nlm.nih.gov/35133415/ 
9. Garvey WT, Frias JP, Jastreboff AM, le Roux CW, Sattar N, Aizenberg D, Mao H, Zhang S, Ahmad NN, Bunck MC, Benabbad I, Zhang XM; SURMOUNT-2 investigators. Tirzepatide once weekly for the treatment of obesity in people with type 2 diabetes (SURMOUNT-2): a double-blind, randomised, multicentre, placebo-controlled, phase 3 trial. Lancet. 2023 Aug 19;402(10402):613-626. Available from: https://pubmed.ncbi.nlm.nih.gov/37385275/ 

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