Ozempic (semaglutide 0.5mg, 1mg, 2mg) and Mounjaro (tirzepatide 2.5mg–15mg) are both GLP-1 receptor agonists used for weight management in the UK. However, there are important differences in their licensing, dosing, and clinical trial results that are worth understanding before choosing between them.
Ozempic is licensed in the UK for type 2 diabetes, not weight loss. It is sometimes prescribed off-label for weight management. Wegovy (semaglutide 2.4mg) is the version of semaglutide licensed specifically for weight loss.
| Feature | Mounjaro | Ozempic |
|---|---|---|
| Active ingredient | Tirzepatide | Semaglutide |
| Mechanism | GLP-1 + GIP dual agonist | GLP-1 agonist |
| UK licence | Weight management | Type 2 diabetes (off-label for weight loss) |
| Doses available | 2.5mg to 15mg | 0.5mg, 1mg, 2mg |
| Average weight loss | ~22.5% | ~6–9% (at diabetes doses) |
| Injection frequency | Once weekly | Once weekly |
| UK price (cheapest) | From ~£139/month | From ~£89/month |
Mounjaro consistently outperforms Ozempic for weight loss in clinical trials. The SURMOUNT-1 trial showed average weight loss of 22.5% of body weight with Mounjaro 15mg, compared to approximately 6–9% with Ozempic at diabetes doses (0.5–2mg). The higher-dose Wegovy (semaglutide 2.4mg) achieves around 14.9% weight loss, still below Mounjaro's results.
- You have type 2 diabetes and want a treatment with a longer track record for blood sugar control
- You are already established on semaglutide and want to continue with the same active ingredient
- Cost is the primary concern — Ozempic is generally cheaper than Mounjaro
- Your prescriber recommends it based on your specific medical history
Ozempic is generally cheaper than Mounjaro in the UK, with the cheapest options starting from around £89/month for the 0.5mg dose. However, at the doses typically used for weight loss (1–2mg), the price difference narrows. Mounjaro's superior weight loss results may make it better value per kilogram lost for many patients.