Semaglutide (Wegovy) vs Tirzepatide (Zepbound)

Semaglutide and tirzepatide are injectable medications used along with diet and exercise to reduce weight. They belong to a class of drugs called glucagon-like peptide-1 (GLP-1) receptor agonists. These medications work by activating the GLP-1 receptor, which is an essential regulator of appetite and food intake. This leads to reduced appetite, increased feelings of fullness, decreased food consumption, and delayed stomach emptying, all of which contribute to weight loss.

Tirzepatide also activates the GIP receptor, in addition to the GLP-1 receptor. Both receptors are involved in appetite regulation. These medications were initially approved for the treatment of type 2 diabetes. However, growing evidence of their weight loss benefits has increased interest in using them for obesity. For weight management, semaglutide is approved under the brand name Wegovy, and tirzepatide is approved under the brand name Zepbound.

Dosing and Side Effects

Both medications are administered once weekly as a subcutaneous injection. Treatment starts with a low dose that is gradually increased to reach a maintenance or target dose. This approach helps reduce the most common gastrointestinal side effects, which include nausea, vomiting, diarrhea, and constipation.

GLP-1 receptor agonists also carry warnings for pancreatitis, gallbladder disease, hypoglycemia, and kidney problems. And when used for diabetes, risk of hypoglycemia increases when combined with insulin or sulfonylureas. They should be avoided in individuals with a history of certain cancers, including a personal or family history of medullary thyroid carcinoma or MEN2. Although serious side effects are less common, patients taking these medications should have their blood glucose and kidney function monitored.

Approved Uses: The two medications differ in the conditions for which they are approved.

Wegovy (semaglutide) is approved for:

• Weight loss and management in obese adults and children aged 12 and older
• Weight loss and management in overweight adults who also have a weight-related medical problem
• Reducing the risk of major cardiovascular events, such as death, heart attack, or stroke, in adults with heart disease who are obese or overweight

Zepbound (tirzepatide) is approved for:

• Weight loss and management in obese adults or in overweight adults who also have a weight-related medical problem
• Treatment of moderate to severe obstructive sleep apnea (OSA) in adults with obesity

Lifestyle and Long-Term Use

These medications are usually prescribed when lifestyle modifications alone have not been effective, or when patients have not been able to maintain benefits from lifestyle changes. They are meant to be used alongside healthy eating and regular exercise, not as a replacement for them. Proper education on lifestyle habits, appropriate medication use, side-effect management, and setting realistic goals is essential, especially since these are intended as long-term treatments. Unfortunately, studies have consistently shown that weight is often regained when GLP-1s are discontinued.

Which Is More Effective?

Current evidence suggests that tirzepatide is more effective than semaglutide for weight loss in patients with obesity who do not have diabetes. In a randomized trial comparing the two medications, participants taking tirzepatide lost 20.2% of their body weight at 72 weeks, compared with 13.7% in the semaglutide group.

The greater weight loss seen with tirzepatide is believed to result from its dual activation of both GLP-1 and GIP receptors. However, weight-loss results can vary among individuals and may be influenced by factors such as baseline weight, adherence to lifestyle changes, and other medical conditions. Both medications are highly effective, and the choice between them may depend on factors like overall health, current medications, age, tolerability, and cost.

Reach out to our team here at MIIS Weight Loss Institute to learn more about your options.

References

1. Novo Nordisk. (2024). Wegovy (semaglutide) injection, for subcutaneous use: Highlights of prescribing information. Novo Nordisk. Retrieved from the FDA website.
2. Eli Lilly and Company. (2024). Zepbound (tirzepatide) injection, for subcutaneous use: Highlights of prescribing information. Eli Lilly and Company. Retrieved from the FDA website.
3. 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. (2025). Tirzepatide as compared with semaglutide for the treatment of obesity. The New England Journal of Medicine. https://doi.org/10.1056/NEJMoa2416394