Treatment Comparison
Mounjaro vs Wegovy: Which Is Better?
Quick Answer: Both Mounjaro (tirzepatide) and Wegovy (injectable semaglutide 2.4 mg) are MHRA-approved once-weekly weight loss injections. Mounjaro produces significantly higher average weight loss — approximately 22.5% vs 14.9% in flagship trials, and approximately 47% more in the 2025 SURMOUNT-5 head-to-head trial. Wegovy has a longer prescribing track record and a cardiovascular risk reduction indication. For most patients seeking maximum weight loss, Mounjaro is the stronger clinical choice. Wegovy — including the new oral tablet — may suit patients who prefer a simpler escalation or needle-free option.~47%more weight loss with Mounjaro vs Wegovy (SURMOUNT-5 2025)
~£30per month cheaper: Mounjaro maintenance vs Wegovy
6 vs 4dose steps: Mounjaro has more steps but lower starting price
Full Comparison
Mounjaro vs Wegovy: Head-to-Head
| Factor | Mounjaro (Tirzepatide) | Wegovy (Semaglutide) |
|---|---|---|
| Drug class | GLP-1/GIP dual agonist | GLP-1 receptor agonist only |
| Manufacturer | Eli Lilly | Novo Nordisk |
| UK licence | MHRA 2023; NICE TA1026 | MHRA 2021; NICE TA875 |
| Dose steps | 6 steps over ~20 weeks | 4 steps over ~16 weeks |
| Avg weight loss (flagship trial) | ~22.5% at 15 mg (SURMOUNT-1, 72 wks) | ~14.9% at 2.4 mg (STEP 1, 68 wks) |
| Head-to-head (SURMOUNT-5) | ~20.2% weight loss | ~13.7% weight loss |
| Waist circumference reduction | ~18.4 cm at 15 mg | ~13.5 cm at 2.4 mg |
| CV risk reduction indication | No (weight management only) | Yes (SELECT trial) |
| Starting price (UK 2026) | ~£129/month (2.5 mg) | ~£149/month (0.25 mg) |
| Maintenance price (UK 2026) | ~£239/month (15 mg) | ~£269/month (2.4 mg) |
| Oral formulation | No — injection only | Yes — Wegovy tablets (2025/26) |
Key Differentiators
When to Choose Each Treatment
Choose Mounjaro if…You want maximum weight loss. You have significant insulin resistance (PCOS, type 2 diabetes, menopausal metabolic changes). You have tried Wegovy without achieving your goals. You want the most evidence-based option per the SURMOUNT-5 head-to-head trial.
Choose Wegovy if…You have established cardiovascular disease (CV risk reduction indication). You prefer fewer dose escalation steps (4 vs 6). You are needle-averse and want the oral tablet option. You prefer a treatment with a longer real-world prescribing track record.
SURMOUNT-5 settled the clinical debate: When compared directly in the same trial under the same conditions, Mounjaro produced approximately 47% more weight loss than Wegovy. For patients making a treatment choice based primarily on efficacy, this provides the clearest available evidence.
FAQs
Frequently Asked Questions
For weight loss efficacy, yes — SURMOUNT-5, the first head-to-head trial, showed tirzepatide produced approximately 47% more weight loss than semaglutide 2.4 mg (20.2% vs 13.7% over 72 weeks). However, Wegovy has a cardiovascular risk reduction indication that Mounjaro does not, and Wegovy is available as an oral tablet from 2025/26.
Mounjaro targets two hunger hormones (GLP-1 and GIP — dual agonist). Wegovy targets one (GLP-1 only). This dual mechanism explains Mounjaro's greater average weight loss. Wegovy has an additional indication for reducing cardiovascular events. Both are once-weekly injections; Wegovy is also available as a daily tablet.
Both have broadly similar GI side effect profiles. Mounjaro's nausea rates (~40%) are broadly comparable to Wegovy's (~44%). Mounjaro has a longer escalation (6 steps vs 4), which distributes the side effect burden over a longer period. Some research suggests Mounjaro's GIP activity may partially mitigate nausea.
Yes — Mounjaro is generally priced slightly lower at comparable dose steps (maintenance ~£239/month vs ~£269/month). Combined with higher weight loss, Mounjaro provides more weight loss per pound spent.
Yes — switching from Wegovy to Mounjaro with clinical guidance is a recognised pathway. Patients who have not achieved their goals on Wegovy may experience renewed and enhanced weight loss on Mounjaro due to the additional GIP mechanism. Discuss the switch with your Happy Pharmacy prescribing team.
Oral semaglutide 7.2 mg (Wegovy tablets) produced approximately 13.6% weight loss in the OASIS 1 trial — slightly less than injectable Wegovy (14.9%) and significantly less than Mounjaro (22.5%). The oral tablet is a viable option for needle-averse patients, but Mounjaro remains the strongest efficacy option for those prioritising maximum weight loss.
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Jastreboff AM et al. SURMOUNT-1. N Engl J Med. 2022. Frías JP et al. SURMOUNT-5. 2025. Wilding JPH et al. STEP 1. N Engl J Med. 2021. NICE TA875. 2023. NICE TA1026. 2024. Happy Pharmacy (GPhC No. 9012585). Educational purposes only.