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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Why Is Mounjaro Increasing in Price?
Mounjaro (tirzepatide) costs have risen significantly in the UK private market over the past year, with prices now ranging from £180–£320+ per month depending on dose and provider. This increase reflects higher manufacturing and distribution costs, increased demand, and market positioning of this dual GIP and GLP-1 receptor agonist. Understanding the reasons behind price changes, and comparing Mounjaro to alternatives like Wegovy, can help you make informed decisions about weight management options available through NHS specialist services or private prescription routes in the UK.
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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.
How Mounjaro and Wegovy Differ in Mechanism and Pricing
Mounjaro (tirzepatide) and Wegovy (semaglutide) are both prescription-only GLP-1-based weight loss injections licensed in the UK, but they work differently and are priced differently. Mounjaro is a dual GIP and GLP-1 receptor agonist — it activates two hormone pathways, which may explain why clinical trials (SURMOUNT) showed average weight loss of approximately 15–21% of body weight. Wegovy is a GLP-1 agonist only, with STEP trial data showing average weight loss of around 15% of body weight. The SURMOUNT trial included larger maximum doses (15 mg tirzepatide vs 2.4 mg semaglutide), and Mounjaro's dual mechanism may require more complex manufacturing, contributing to higher costs. Current Mounjaro UK pricing typically ranges from £180–£320+ monthly, whilst Wegovy costs range from £129–£250+ monthly, depending on your dose and the private provider. NHS access varies by region, with both medications available through specialist tier 3/4 weight management services, though waiting times can be substantial.
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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.
Why Mounjaro Costs More and What This Means for You
Mounjaro's higher price reflects several factors: the dual-mechanism manufacturing complexity, increased demand as awareness grows, patented formulation with the KwikPen delivery system, and market positioning as a newer, more potent option. Newer medications often command premium pricing before generic or biosimilar versions become available — tirzepatide is relatively new compared to semaglutide. Additionally, Mounjaro requires dose titration starting at 2.5 mg and escalating weekly up to 15 mg, meaning you purchase more pens initially than with Wegovy's lower maximum dose. Both medications require a UK prescription from a licensed prescriber following a clinical assessment. Your choice between them depends on individual suitability, prescriber recommendation, and budget. Try our GLP-1 weight loss calculator to project outcomes at different doses, and use our BMI calculator to check your current health baseline before consulting a prescriber about which option suits you best.
- 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 prices have risen due to increased manufacturing and distribution costs, higher demand as awareness grows, and market positioning as a premium dual GIP+GLP-1 medication. As a newer, more complex formulation than single-mechanism alternatives, it commands higher pricing. Prices may eventually fall once biosimilar versions become available in future years.
Is Mounjaro more effective than Wegovy?
Clinical trials show Mounjaro (average 15–clinically studied weight loss) and Wegovy (average clinically studied weight loss) have overlapping effectiveness ranges. Individual results vary significantly. The dual GIP+GLP-1 mechanism may suit some people better, but both require a prescriber's assessment to determine personal suitability. Effectiveness depends on lifestyle changes, dose tolerance, and individual biology.
Can I get Mounjaro on the NHS?
Yes. Mounjaro is available through NHS specialist tier 3/4 weight management services for eligible adults with BMI ≥30, or ≥27 with weight-related health conditions. However, access varies significantly by region and waiting lists can be very long in many areas. Private prescription is available without NHS referral for faster access.
What is the difference between a GLP-1 and a GIP+GLP-1 medication?
GLP-1 medications (like Wegovy) activate one hormone pathway to reduce appetite and slow digestion. Mounjaro activates two pathways — GLP-1 and GIP — which may amplify appetite suppression and blood sugar regulation. The dual mechanism requires more complex manufacturing, contributing to higher costs.
Which is cheaper — Mounjaro or Wegovy?
Wegovy is typically cheaper (£129–£250+ monthly) than Mounjaro (£180–£320+ monthly) through private prescription. However, pricing varies by dose and provider. Both require clinical assessment. Check current availability and pricing with registered UK pharmacies, and discuss with your prescriber which option suits your health profile and budget.
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.