The UK's most complete GLP-1 guide
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- How GLP-1 medications work
- Mounjaro vs Wegovy compared
- Injection instructions
- Side effects & solutions
- What to eat on treatment
- FAQs answered
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Mounjaro 10 mg vs Wegovy: Price and Effectiveness Comparison
If you're considering weight loss medication in the UK, you've likely encountered both Mounjaro (tirzepatide) and Wegovy (semaglutide). Both are prescription-only injections licensed for weight management, but they differ in mechanism, dosing, and cost. Understanding the price of Mounjaro 10 mg alongside Wegovy — and how they compare in clinical effectiveness — can help you and your prescriber decide which may be right for you. This guide explains the differences factually, without suggesting one is superior to the other.
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What Is BMI and Why Does It Matter?
Body Mass Index (BMI) is the most widely used screening tool for assessing whether your weight falls within a healthy range. Used by the NHS, GPs, and weight management services across the UK, BMI provides a quick snapshot of your weight relative to your height. The formula is simple: your weight in kilograms divided by your height in metres squared (kg/m²).
While BMI isn't a perfect measure — it doesn't account for muscle mass, bone density, or fat distribution — it remains the standard first step in identifying potential weight-related health risks including type 2 diabetes, cardiovascular disease, high blood pressure, and certain cancers.
The NHS also recommends adjusted thresholds for people of South Asian, Chinese, or Black African heritage — a BMI of 23 or above is classified as overweight, and 27.5 as obese. Our calculator includes this adjustment as a one-click toggle.
How Mounjaro and Wegovy Work Differently
Mounjaro (tirzepatide) is a dual GIP and GLP-1 receptor agonist, meaning it activates two hormone pathways in your body. This dual mechanism may help regulate appetite, increase feelings of fullness, and slow gastric emptying. At the 10 mg dose — a mid-range Mounjaro KwikPen strength — clinical trial data from SURMOUNT-1 showed participants lost an average of approximately 19.5% of body weight over 72 weeks, alongside a reduced-calorie diet and increased physical activity.
Wegovy (semaglutide) is a GLP-1 receptor agonist only, activating a single hormone pathway. Its maximum dose is 2.4 mg weekly. In the STEP-1 clinical trial, participants on 2.4 mg Wegovy lost an average of approximately 14.9% body weight over 68 weeks under similar conditions. Both medications work best alongside lifestyle changes — neither replaces diet and exercise.
- Mounjaro: dual mechanism (GIP + GLP-1)
- Wegovy: single mechanism (GLP-1 only)
- Both: once-weekly injections, prescription-only, require clinical assessment
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If your BMI suggests you're overweight or obese, explore our GLP-1 calculators to project potential weight loss on Mounjaro or Wegovy.
Use our progress tracker to log your weight weekly, visualise your journey with charts, and stay motivated — all stored privately in your browser.
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UK Pricing and Availability: What You Need to Know
Mounjaro 10 mg price and Wegovy pricing vary significantly depending on where you obtain them. On the NHS, both medications are available through specialist tier 3 weight management services, though access depends on your local integrated care board (ICB) and existing waiting lists can be substantial. On the private market, prices typically range from £129 to £320 per month depending on dose, supplier, and whether you're initiating or maintaining treatment. A Mounjaro KwikPen (4 weekly injections) costs less than the cumulative price of four individual Wegovy pens at equivalent stages of titration, but direct cost comparisons are complex because the dose escalation schedules differ. Your prescriber will assess your individual suitability — cost alone should not drive the decision between the two.
- Dual GIP/GLP-1 receptor agonist
- Up to 22.5% body weight loss (SURMOUNT-1)
- Weekly injection, dose escalation over 20+ weeks
- Available via private prescription in the UK
- Doses: 2.5mg → 5mg → 7.5mg → 10mg → 12.5mg → 15mg
- GLP-1 receptor agonist
- Up to 15–17% body weight loss (STEP trials)
- Weekly injection, 5-step dose escalation
- NHS & private prescription available
- Doses: 0.25mg → 0.5mg → 1mg → 1.7mg → 2.4mg
Mounjaro vs Wegovy: Head-to-Head
A side-by-side comparison of the two most popular GLP-1 weight loss medications available in the UK.
| Feature | Mounjaro | Wegovy |
|---|---|---|
| Drug class | Dual GIP/GLP-1 agonist | GLP-1 agonist |
| Active ingredient | Tirzepatide | Semaglutide |
| Avg. weight loss | 15–22.5% | 12–17% |
| Key trial | SURMOUNT-1 (2022) | STEP 1 (2021) |
| Max dose | 15 mg weekly | 2.4 mg weekly |
| Escalation period | 20–32 weeks | 16–20 weeks |
| Administration | Weekly injection (pen) | Weekly injection (pen) |
| NHS availability | Private prescription only | NHS & private |
| Approx. private cost | £150–£250/month | £150–£300/month |
| Common side effects | Nausea, diarrhoea, constipation | Nausea, vomiting, diarrhoea |
Data sourced from SURMOUNT-1 and STEP 1 clinical trials. Costs are approximate and vary by provider. Always consult a prescriber.
Am I Eligible for Weight Loss Medication?
In the UK, eligibility for GLP-1 weight loss medications like Mounjaro and Wegovy is based on your BMI and overall health profile.
- BMI of 30 or above (obese)
- Age 18 or over
- No contraindicated conditions
- Committed to lifestyle changes
- BMI of 27 or above
- Plus type 2 diabetes
- Or high blood pressure
- Or obstructive sleep apnoea
Use our BMI calculator to check whether your BMI falls within the eligible range.
How We Built These Tools
Every calculator and guide on myweightcheck is built with accuracy and transparency in mind. Our BMI calculator uses the standard WHO formula with NHS-aligned category thresholds. Our GLP-1 projections are modelled on published clinical trial data from SURMOUNT and STEP studies.
All data stays on your device. We don't require sign-ups, and we don't store your health information on any server. Your progress tracker saves data locally in your browser using localStorage, so only you can see it.
We're based in the UK and our tools are designed specifically for UK users — supporting stone & lbs by default, referencing NHS guidelines, using NICE-approved medication data, and linking to GPhC-registered pharmacies.
Frequently Asked Questions
Common questions about BMI, weight loss medications, and our free UK tools.
What's the key difference between Mounjaro 10 mg and Wegovy in how they work?
Mounjaro is a dual GIP and GLP-1 agonist (two hormone pathways), while Wegovy is GLP-1 only (single pathway). This dual mechanism may explain why Mounjaro users saw higher average weight loss in clinical trials, though individual results vary significantly. Both slow stomach emptying and reduce appetite. Your prescriber chooses based on your health history and suitability, not just trial data.
Is Mounjaro 10 mg available on the NHS?
Yes, Mounjaro is NICE-approved for NHS use within specialist tier 3 weight management services. However, availability varies by region and waiting lists can be lengthy. You'd typically need a GP referral to access NHS specialist services. Private prescribing is also available through UK-licensed online prescribers if you meet clinical eligibility criteria.
How does Mounjaro 10 mg pricing compare to Wegovy?
Private Mounjaro KwikPen costs typically range from £129–£320 monthly depending on dose and supplier. Wegovy pricing is similar. NHS access removes direct cost but involves waiting lists and regional variation. Always clarify pricing with your provider upfront — costs vary by dose, supply quantity, and service. Use our GLP-1 weight loss calculator to project potential outcomes for either medication.
Can I switch from Wegovy to Mounjaro or vice versa?
Switching between medications must be managed by your prescriber. There's no official established conversion chart — approximate equivalences exist (e.g., Mounjaro 10 mg ≈ Wegovy 1.7 mg), but switching requires clinical oversight. Your prescriber will assess whether the switch is appropriate and manage any dose adjustments carefully.
Which medication should I choose?
Neither medication is universally "better" — suitability depends on your individual health profile, tolerability, access, and cost. Your prescriber conducts a clinical assessment to determine which is appropriate for you. Calculate your personal BMI using our free BMI calculator above, then discuss both options with your GP or prescriber to make an informed decision together.
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