Mounjaro vs Wegovy

What’s the difference between Wegovy and Mounjaro?

Wegovy (semaglutide) and Mounjaro (tirzepatide) are both weekly injectable medications approved for the treatment of type 2 diabetes and for chronic weight management in adults living with obesity or overweight with at least one weight related condition.

Although they share some similarities, there are key differences in their mechanisms of action, efficacy, and potential side effects.

Do Mounjaro and Wegovy work in the same way?

Mechanism of Action

Wegovy (semaglutide) mimics the action of glucagon-like peptide-1 (GLP-1), a hormone involved in appetite regulation and insulin secretion. By activating GLP-1 receptors, semaglutide increases insulin release in response to high blood sugar and decreases glucagon secretion This helps to reduce appetite and slows gastric emptying making you feel fuller for longer. It also reduces cravings.

Mounjaro (tirzepatide) is a dual GIP (Glucose-dependent Insulinotropic Polypeptide) and GLP-1 receptor agonist, which means it targets two pathways. Along with the benefits provided by GLP-1 receptor activation similar to Wegovy, Mounjaro also activates GIP receptors, which enhances its effects on blood sugar control and weight loss. The dual mechanism is believed to offer more comprehensive benefits for managing diabetes and weight compared to GLP-1 agonists alone.

Can I expect to lose more weight with Mounjaro than Wegovy?

Efficacy

Clinical trials have shown both medications to be effective in lowering blood glucose levels in people with type 2 diabetes and in promoting significant weight loss in individuals living with obesity or overweight. However, the dual-action mechanism of Mounjaro offers an advantage in terms of efficacy for some patients, leading to greater reductions in blood sugar levels and more significant weight loss compared to GLP-1 agonists like Wegovy. You can expect to lose 15% of your starting weight after 52 weeks on Wegovy but with Mounjaro it’s estimeated that you could lose 20% of your starting weight.

Are the side effects different between Mounjaro and Wegovy?

Side Effects

Common side effects of both medications include gastrointestinal issues such as nausea, vomiting, diarrhoea, constipation, and abdominal pain. These side effects are generally mild to moderate and tend to decrease over time as your body gets used to the medication. However, the incidence and severity of side effects may vary between individuals and between the two medications.

There are also specific warnings and precautions associated with each medication, and their use may be contraindicated in certain individuals with particular medical conditions or histories. For example, Wegovy can be prescribed until you are 74 years of age but Mounjaro can be prescribed up until you’re 84.

Both Wegovy and Mounjaro should not be used during pregnancy, as it is not known if they may affect your unborn child. Therefore, it is recommended to use contraception while using both medications.

Eli Lily, the manufacturer of Mounjaro, recommends that If you wish to become pregnant, you should stop using Mounjaro at least one month in advance but Novo Nordisk, the Manufacturer of Wegovy recommends stopping it at least two months in advance.

Is Mounjaro better than Wegovy?

Conclusion

Wegovy and Mounjaro have been game changers in the battle against obesity. Mounjaro's dual-action mechanism may offer advantages for some patients, but both medications can produce significant weight loss when used in conjunction with a healthy lifestyle.

Medically reviewed by
Superintendent pharmacist Margaret Hudson BSc(Hons) MRPharmS
26th March 2024