The UK's most complete GLP-1 guide
Every Question Answered. Every Side Effect Explained.
- 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 5ml Cost vs Wegovy — What You Need to Know
Understanding the cost difference between Mounjaro (tirzepatide) and Wegovy (semaglutide) is important when considering weight loss treatment in the UK. Both are prescription-only GLP-1 medications, but they differ significantly in pricing, dosing schedules, and how they work. This guide compares the costs, mechanisms, and suitability of each to help you make an informed decision alongside your GP or prescriber.
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Enter your height and weight below. Supports both imperial (stone & lbs) and metric (kg). Results include NHS category, healthy weight range, and ethnicity adjustments.
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.
Cost Comparison and Clinical Trial Results
Mounjaro costs approximately £129–£160 per KwikPen on the private market in the UK, with each pen containing 4 doses (4 weeks). At the standard maintenance dose of 10 mg, monthly costs range from £129–£160. Wegovy typically costs £149–£249 per month depending on dose and provider. The dose titration schedules also differ: Mounjaro escalates from 2.5 mg over 16–20 weeks, whilst Wegovy escalates from 0.25 mg over 16 weeks.
Clinical trial results show different averages: Mounjaro achieved approximately 19.5% average weight loss at 10 mg dose (SURMOUNT-1 trial), whilst Wegovy achieved approximately 14.9% at maximum 2.4 mg dose (STEP-1 trial). However, individual results vary significantly and are not assured. Both medications require a reduced-calorie diet and increased physical activity to achieve results. Use our GLP-1 weight loss calculator to see projected weight loss at different doses.
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How It Works
Three simple steps to understand your weight and take action.
Enter your height and weight in our free calculator. Get your BMI, NHS category, healthy weight range, and ethnicity-adjusted thresholds instantly.
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.
Free Weight Loss Tools & Guides
Everything you need to understand your weight, explore medication options, and track your progress — completely free.
NHS Access and Individual Suitability
Both Mounjaro and Wegovy are available through NHS specialist tier 3 weight management services, though availability and waiting times vary significantly across UK regions. Private access is available without NHS referral through GPhC-registered online prescribers following clinical assessment. A prescriber will assess your BMI, health conditions, and medication interactions to determine which is suitable for you. Some patients may respond better to one medication than the other due to individual metabolism and health profile. Your GP can refer you to NHS services, or you can explore private options. Try our BMI calculator above to check your eligibility threshold.
- 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.
Why is Mounjaro sometimes cheaper than Wegovy in the UK?
Mounjaro costs are often lower because each KwikPen contains 4 doses, spreading cost across a month. Wegovy pricing depends on the specific dose; higher doses (1.7 mg, 2.4 mg) cost more. Individual prices vary by private provider, so it's worth checking multiple sources before committing.
How does Mounjaro's mechanism differ from Wegovy?
Mounjaro (tirzepatide) is a dual GIP and GLP-1 receptor agonist, whilst Wegovy (semaglutide) is a GLP-1 only agonist. The dual mechanism in Mounjaro may provide different appetite and satiety effects. Both work similarly on gastric emptying and blood sugar, but individual response varies.
Can I switch between Mounjaro and Wegovy on the NHS?
Switching is possible but requires prescriber approval and reassessment. There is no official conversion chart—any switch must be managed by your GP or specialist service. Approximate dosing equivalences exist, but your prescriber will determine the appropriate new dose for you.
What's the typical cost difference over a year?
Mounjaro at 10 mg costs roughly £1,548–£1,920 annually. Wegovy at 2.4 mg costs roughly £1,788–£2,988 annually. Costs vary by provider and dose. Private prices change regularly, so compare current quotes from multiple GPhC-registered pharmacies.
Does NHS cover the full cost of either medication?
NHS specialist services prescribe both medications, and there's no patient cost through NHS. However, availability is limited and varies by region. Private prescriptions require full payment. Check your local integrated care board (ICB) for NHS availability in your area.
Ready to take control of your weight loss journey?
Start with a free BMI check, explore your GLP-1 options, or begin tracking your progress today. No sign-up. No cost. Just results.