Ozempic vs Mounjaro
Semaglutide vs tirzepatide, side by side, including the thing people miss: in the UK, Ozempic is a diabetes medicine, not a weight-loss one.
Updated 30 October 2026
| Ozempic | Mounjaro | |
|---|---|---|
| Active ingredient | semaglutide | tirzepatide |
| Drug class | GLP-1 | Dual GIP + GLP-1 |
| How often | Once a week | Once a week |
| Licensed in the UK for | Type 2 diabetes, not weight loss | Weight management (also type 2 diabetes) |
| Not every GLP-1 is licensed for weight loss in the UK. Ozempic is a diabetes medicine. | ||
| Pen | Ozempic pen | KwikPen |
| Starting dose | 0.25 mg | 2.5 mg |
| Maintenance dose | 0.5 or 1 mg (up to 2 mg) | 5, 10 or 15 mg |
| Highest dose | 2 mg | 15 mg |
| Storage once in use | Up to 6 weeks below 30 °C | Up to 30 days below 30 °C |
| Average weight loss in trials | No weight-loss trial (licensed for diabetes) | about 21% (SURMOUNT-1, 72 weeks (15 mg)) |
| Trial figures are averages over the whole study, at the top dose. Real-world results vary. | ||
| NHS availability | On NHS for type 2 diabetes, not for weight loss | On NHS weight-management pathways (criteria apply) |
Head to head
In SURMOUNT-5, the first head-to-head trial, average weight loss over 72 weeks was 20.2% with tirzepatide versus 13.7% with semaglutide. It was an open-label trial funded by the maker of tirzepatide. SURMOUNT-5 (NEJM).
Thinking of switching?
There’s no simple dose-for-dose swap between these; they’re different medicines. A switch means starting the new one at its lowest dose and titrating up again, under your prescriber. People’s experience of switching varies a lot, so the GLP-1 communities are worth a read for the lived side.
Facts from the UK SmPCs (Ozempic, Mounjaro) and the trials linked above.
This compares the facts; it doesn’t say which is right for you. That’s a decision for you and your prescriber.
Common questions
- Is Ozempic the same as Mounjaro?
- No. Ozempic is semaglutide (a GLP-1), Mounjaro is tirzepatide (a dual GIP/GLP-1). Both are once-weekly injections, but in the UK Ozempic is licensed for type 2 diabetes, not weight loss, while Mounjaro is licensed for weight management.
- Can I get Ozempic for weight loss on the NHS?
- No, Ozempic is on the NHS for type 2 diabetes, not weight loss. The semaglutide licensed for weight management in the UK is Wegovy.
- Which causes more weight loss?
- There isn’t a weight-loss trial for Ozempic because it isn’t licensed for that use. For the semaglutide weight-loss evidence, see Wegovy (STEP-1, about 15%); tirzepatide reached about 21% in SURMOUNT-1. Averages don’t predict any one person’s result.