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 Prices in the UK — Comparison with Wegovy
Mounjaro (tirzepatide) costs vary in the UK depending on whether you access it through the NHS or privately. Private Mounjaro prices typically range from £130 to £320 per month, varying by dose. Wegovy (semaglutide), an alternative GLP-1 injection, has similar private pricing. Both are prescription-only medicines requiring clinical assessment. NHS access is available through specialist tier 3/4 weight management services, though availability and waiting times vary significantly by region. Understanding the cost differences, how each medication works, and which might suit you is essential before starting treatment.
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Calculate Your BMI Instantly
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.
Mounjaro vs Wegovy — Price and Mechanism Differences
Private UK pricing: Mounjaro costs approximately £130–£320 per month depending on dose, with starter doses (2.5 mg to 5 mg) at the lower end and maintenance doses (10 mg to 15 mg) at the higher end. Wegovy (semaglutide), a GLP-1-only injection, has comparable private pricing in similar dose ranges.
Key mechanism difference: Mounjaro is a dual GIP and GLP-1 receptor agonist — it activates two hormone pathways — whereas Wegovy is a GLP-1-only agonist. Clinical trials (SURMOUNT for Mounjaro, STEP for Wegovy) showed Mounjaro achieved slightly higher average weight loss (15–21% body weight) compared to Wegovy (approximately 15% body weight), though individual results vary significantly.
Dose titration: Mounjaro KwikPen dosing starts at 2.5 mg weekly and escalates over 20 weeks to maximum 15 mg. Wegovy starts at 0.25 mg and escalates to maximum 2.4 mg. Both require minimum 4 weeks at each dose before increasing.
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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, Prescription Requirements, and Individual Suitability
NHS access: Both Mounjaro and Wegovy are available through NHS specialist weight management services (tier 3/4), though access varies by region (ICB). NICE has approved tirzepatide for use within NHS specialist services. Waiting lists can extend many months in some areas. Private access is through GPhC-registered online pharmacies following clinical assessment by a UK-licensed prescriber — no NHS referral required.
Eligibility: Both medications require BMI ≥30, or BMI 27–29.9 with weight-related health conditions. A prescriber will assess individual suitability based on medical history, medications, and health goals. Individual results vary — neither medication assures specific weight loss. Use our free GLP-1 weight loss calculator to estimate potential outcomes at different doses alongside your own diet and activity changes.
- 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.
How much does Mounjaro cost privately in the UK?
Private Mounjaro prices in the UK typically range from £130 to £320 per month depending on dose. Starting doses (2.5 mg to 5 mg) cost less, while maintenance doses (10 mg to 15 mg) cost more. Each KwikPen contains 4 weeks of medication. Prices vary between providers, so shop around.
Is Mounjaro cheaper than Wegovy in the UK?
Private pricing for Mounjaro and Wegovy is broadly comparable in the UK, typically £130–£320 per month. The cost difference depends more on your chosen dose and provider than on the medication itself. Mounjaro's dual mechanism may offer slightly different results, but suitability should be based on clinical assessment, not price alone.
Can I get Mounjaro free on the NHS in the UK?
Yes, Mounjaro (tirzepatide) is available through NHS specialist weight management services. Access requires referral from your GP to a tier 3/4 specialist centre in your area. Availability varies significantly by region and waiting times can be lengthy. Contact your local integrated care board (ICB) to check availability.
What is the difference between Mounjaro and Wegovy?
Mounjaro (tirzepatide) is a dual GIP and GLP-1 receptor agonist, activating two hormone pathways. Wegovy (semaglutide) is a GLP-1-only agonist. Clinical trials showed Mounjaro achieved slightly higher average weight loss (up to 21% body weight) versus Wegovy (approximately 15%), though individual results vary. Both require clinical assessment before prescription.
Do I need a prescription for Mounjaro in the UK?
Yes, Mounjaro is prescription-only in the UK. You require a prescription from a licensed GP or prescriber following a clinical assessment. Private prescribers assess suitability online; NHS prescribers assess through specialist weight management services. You cannot buy Mounjaro without a valid UK prescription.
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.