In short
Overview
Mounjaro and Ozempic are both weekly injections, but they differ in how much weight they take off and in what they are licensed for.
Direct Answer
Mounjaro versus Ozempic comes down to weight loss, heart disease and licence. Mounjaro (tirzepatide) produces more weight loss and beat semaglutide 2.4 mg in a head-to-head trial; semaglutide is preferred in people with heart disease and no diabetes, the only group in which it has proven cardiovascular benefit.
Ozempic is semaglutide licensed for type 2 diabetes. For weight loss without diabetes, the licensed semaglutide product is Wegovy (European Medicines Agency).
Who This Applies To
- People choosing a first weight loss injection.
- People on Ozempic who want more weight loss.
- People with heart disease, diabetes or sleep apnoea.
- People comparing prices of the two injections.
Option Comparison / Decision Criteria
What do the trials show for Mounjaro and semaglutide?
Both injections produce large weight loss, with tirzepatide ahead. The tables set out the main results.
| Dose | Mean weight change |
|---|---|
| 5 mg | Minus 15 percent |
| 10 mg | Minus 19.5 percent |
| 15 mg | Minus 20.9 percent |
| Placebo | Minus 3.1 percent |
| Result | Semaglutide vs placebo |
|---|---|
| Mean weight change | Minus 15.3 kg vs minus 2.6 kg |
| At least 10 percent loss | 69.1 vs 12.0 percent |
| At least 15 percent loss | 50.5 vs 4.9 percent |
Which injection fits which situation?
| Situation | Usual choice |
|---|---|
| Maximum weight loss | Tirzepatide |
| Heart disease without diabetes | Semaglutide |
| Obstructive sleep apnoea | Tirzepatide |
| Type 2 diabetes | Either, with more options |
Why an In-Person Physician Review Matters
Do Mounjaro and semaglutide differ in side effects?
Mounjaro and semaglutide share the same side effects: nausea in 25 to 40 percent, and vomiting, diarrhoea or constipation in 10 to 20 percent, mostly during dose increases. Both are monitored for reflux, pancreatitis and gallbladder disease, and both are never used in pregnancy or with a personal or family history of medullary thyroid cancer.
Frequently Asked Questions
Mounjaro loses more weight; tirzepatide beat semaglutide 2.4 mg in a head-to-head trial.
Semaglutide is preferred with heart disease and no diabetes, where it has proven cardiovascular benefit.
No, Ozempic is licensed for type 2 diabetes; Wegovy is the semaglutide product licensed for weight management.
No, both mainly cause nausea, vomiting, diarrhoea and constipation during dose increases.
Evidence
Where this information comes from
Every figure on this page is taken from the sources below. All of them are free to read, so you can check them yourself.
- Mounjaro KwikPen: Summary of Product Characteristics
- Wegovy: European public assessment report
- Ozempic: European public assessment report
- Overweight and obesity management (NG246)
This page is general medical information and does not replace a personal consultation. Trial results are averages across large groups, not a prediction for any one person.