Mounjaro vs Wegovy for Weight Loss
A balanced comparison of Mounjaro (tirzepatide) and Wegovy (semaglutide) — mechanism, effectiveness, cost, and side effects.
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Two different medications, similar goal
Mounjaro (tirzepatide) and Wegovy (semaglutide) are both injectable weight-loss medications available privately in the UK. They work in similar but distinct ways:
| Feature | Mounjaro | Wegovy |
|---|---|---|
| Active ingredient | Tirzepatide | Semaglutide |
| Mechanism | Dual GLP-1 + GIP agonist | GLP-1 agonist only |
| Average weight loss (trials) | 15–22.5% | ~15% |
| Injection frequency | Once weekly | Once weekly |
| UK availability | Private prescription | Private + limited NHS |
| Typical monthly cost (private) | £100–£250 | £150–£300 |
Key differences
- Effectiveness: Head-to-head trials are limited, but Mounjaro's dual mechanism has shown higher average weight loss in separate trials
- Cost: Prices vary by provider and dose, but Mounjaro is often slightly cheaper per month at equivalent stages
- Side effects: Both cause similar GI side effects (nausea, diarrhoea, constipation). These typically improve with dose titration
- Availability: Both can have supply issues. Wegovy has limited NHS availability; Mounjaro is currently private-only for weight loss
Which should you choose?
This is a clinical decision that should be made with your prescriber. Factors include your health profile, previous medication history, budget, and personal preferences. Both medications can be effective for weight loss when used alongside lifestyle changes.
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Use our Mounjaro vs Wegovy Calculator to compare projected weight loss and costs based on your own inputs.
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Related calculators
- Mounjaro vs Wegovy Calculator — Enter your weight and the monthly costs of each medication to compare projected weight loss, total spend, and cost per kilogram lost over yo
- Mounjaro Weight Loss Calculator — This planning tool projects how much weight you could lose over a chosen number of weeks, using conservative, moderate, or ambitious assumpt
- Mounjaro Protein Calculator — Find out how much protein you should aim for each day and per meal to support muscle preservation during weight loss on GLP-1 medication.
- Mounjaro Calorie Calculator — Calculate your maintenance calories and a safe deficit range to support steady weight loss alongside Mounjaro treatment.
- Mounjaro Calorie Deficit Calculator — Enter your maintenance calories and a target intake (or desired weekly loss) to see the size of your deficit and projected weight change ove
- BMI Calculator for Mounjaro — Find your BMI, see which category it falls into, and understand how it relates to eligibility criteria for treatments like Mounjaro.
Related guides
- How Many Calories Should You Eat on Mounjaro? — Understanding your calorie needs during Mounjaro treatment — maintenance, deficit, and safe intake ranges explained.
- How Much Protein Should You Eat on Mounjaro? — Why protein matters during GLP-1 weight loss and how to hit your daily target with practical meal guidance.
- How Much Weight Can You Lose on Mounjaro? — A realistic look at expected weight loss on Mounjaro (tirzepatide), based on clinical trial data and practical planning advice.
- What BMI Means for Weight-Loss Injections — How BMI is used to assess eligibility for weight-loss medications like Mounjaro and Wegovy, and its limitations.
Last updated
Last reviewed: 2026-04-12T10:29:26.079Z.