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 Price Increase in the UK — What You Need to Know
Mounjaro (tirzepatide) pricing in the UK has increased over recent months as demand for GLP-1 weight loss medications continues to rise. Understanding the cost differences between Mounjaro and Wegovy, and how pricing works, can help you make an informed decision alongside your prescriber. Both are prescription-only medicines requiring a clinical assessment, and costs vary depending on dose and private provider. Use our free GLP-1 weight loss calculator to explore potential outcomes with either medication, and discuss pricing and eligibility with your GP or a licensed 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.
Mounjaro vs Wegovy — Mechanism, Efficacy, and Cost Differences
Mounjaro (tirzepatide) is a dual GIP and GLP-1 receptor agonist — meaning it activates two hormone pathways rather than one. Clinical trials (SURMOUNT-1) showed average weight loss of approximately 15–21% of body weight at the maximum 15 mg dose. Wegovy (semaglutide) is a GLP-1 agonist only, with average weight loss of approximately 14.9% at the maximum 2.4 mg dose in STEP trials. Both are once-weekly injections available on NHS specialist services or private prescription in the UK.
Pricing differences reflect mechanism complexity and manufacturing costs. Mounjaro typically costs more per dose than Wegovy privately — though exact prices vary by provider and dose. The 15 mg Mounjaro KwikPen may cost £200–£320 monthly, while Wegovy can range from £129–£250 depending on your dose level. Always compare current prices from registered UK pharmacies, as pricing changes frequently and varies significantly between providers.
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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.
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Choosing Between Mounjaro and Wegovy — What Matters Most
The choice between Mounjaro and Wegovy depends on individual factors that only a prescriber can assess: your health history, existing medications, BMI, weight-related conditions, and how each medication's mechanism might suit you. Neither is inherently "better" — they work via different pathways and individual responses vary significantly. Some people lose more weight on Mounjaro's dual mechanism; others respond equally well to Wegovy's single mechanism. Your GP or licensed prescriber will discuss both options, pricing, and which is most appropriate for you.
If cost is a primary concern, discuss this openly with your prescriber. NHS access through specialist weight management services may be free, though waiting lists vary by region. Private pricing is transparent but varies — compare providers using our free BMI calculator to confirm your eligibility first, then discuss cost alongside clinical suitability with your chosen prescriber.
- 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 has Mounjaro become more expensive in the UK?
Mounjaro price increases reflect growing demand, manufacturing supply adjustments, and the complexity of tirzepatide's dual GIP+GLP-1 mechanism. Currency fluctuations and distribution costs also affect pricing. Prices vary between providers and doses, so comparing quotes from GPhC-registered pharmacies is essential.
Is Mounjaro more effective than Wegovy because it costs more?
Higher cost does not equal higher efficacy. Mounjaro showed slightly higher average weight loss in trials (15–21%) versus Wegovy (14.9%), but differences are modest and individual results vary significantly. Effectiveness depends on your personal response, adherence, and lifestyle changes — not price.
Can I get Mounjaro or Wegovy free on the NHS?
Yes, both are available through NHS tier 3 specialist weight management services if you meet eligibility criteria (BMI ≥30, or ≥27 with weight-related conditions). NHS access is free but availability and waiting times vary significantly by region and local ICB.
How do I know if I'm eligible for Mounjaro or Wegovy?
Both require a BMI of 30 kg/m² or above, or 25–29.9 with weight-related health conditions (diabetes, hypertension, cardiovascular disease). Use our free BMI calculator to check your status, then discuss eligibility with your GP or a licensed prescriber who will conduct a full clinical assessment.
What's the difference between Mounjaro's mechanism and Wegovy's?
Mounjaro activates both GIP and GLP-1 hormone pathways (dual action), while Wegovy activates GLP-1 only. This dual mechanism may explain Mounjaro's slightly higher average weight loss in trials, but both reduce appetite, slow stomach emptying, and support weight loss when combined with diet and exercise.
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.