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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How Much Is Mounjaro In The UK?
Mounjaro (tirzepatide) costs vary significantly in the UK depending on whether you access it through the NHS or privately. NHS access is through specialist tier 3 weight management services with no direct patient cost, though waiting lists can be lengthy. Private prescriptions typically range from £150 to £350 per month depending on dose, though exact pricing varies between providers. Understanding both cost and clinical differences between Mounjaro and Wegovy helps you make an informed decision with your 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: Cost, Mechanism, and Clinical Trial Data
Mounjaro (tirzepatide) is a dual GIP and GLP-1 receptor agonist, meaning it activates two separate hormone pathways. In the SURMOUNT-1 clinical trial, participants on the maximum 15 mg dose lost an average of 20.9% of their 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. The STEP-1 clinical trial showed participants on 2.4 mg lost an average of 14.9% of body weight over 68 weeks with the same lifestyle support.
- Mounjaro: once-weekly injection, maximum 15 mg dose
- Wegovy: once-weekly injection, maximum 2.4 mg dose
- Both require a UK prescription and clinical assessment
- Both are available through NHS specialist services or private prescribing
- Individual results vary significantly between users
The dual mechanism of Mounjaro may contribute to its slightly higher average weight loss in clinical trials, though this does not assures better results for every individual. Your prescriber will assess which medication is more suitable based on your health profile and medical history.
Clinically BackedWeight Loss
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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 vs Private Prescribing In The UK
NHS access to Mounjaro for weight management is through NICE-approved specialist tier 3 or tier 4 weight management services. You'll need a referral from your GP, and availability varies significantly by region (Integrated Care Board). Waiting lists can extend from several months to over a year in many areas. Once approved and prescribed, there is no direct cost to you.
Private prescribing is available through online consultations with UK-licensed prescribers. After a brief assessment, if suitable, a prescription is issued to a GPhC-registered pharmacy. Private Mounjaro typically costs £150–£350 per month depending on dose, with some variation between providers. Private access doesn't require NHS referral and is often faster than NHS routes. Try our GLP-1 weight loss calculator to estimate potential results at different doses, and use our BMI calculator to assess your starting point.
- 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.
Is Mounjaro available on the NHS in the UK?
Yes, Mounjaro is available through NHS specialist weight management services following NICE approval. Access requires a GP referral to tier 3 services. Availability and waiting times vary by region. Once prescribed through the NHS, there is no cost to you, but waiting lists can be lengthy in many areas.
How much does Mounjaro cost privately in the UK?
Private Mounjaro typically costs between £150 and £350 per month depending on dose and provider. The 2.5 mg starting dose is usually cheaper than higher doses. Private prescriptions require an online assessment with a UK-licensed prescriber, and medication is dispensed by a GPhC-registered pharmacy.
Is Mounjaro cheaper than Wegovy in the UK?
Pricing is similar between Mounjaro and Wegovy when prescribed privately, typically £150–£350 per month. NHS costs are the same (free if prescribed). The main difference is the mechanism: Mounjaro is a dual GIP/GLP-1 agonist, while Wegovy is GLP-1 only. Clinical trial data shows Mounjaro achieved slightly higher average weight loss, though individual results vary.
What is a Mounjaro KwikPen and how long does it last?
A Mounjaro KwikPen is a pre-filled injection device containing four weekly doses (one month's supply). Each pen is a single-use device with four doses inside. After four weeks, you would typically require a new prescription and new pens from your provider.
Do I need a prescription for Mounjaro in the UK?
Yes, Mounjaro is prescription-only in the UK. It is not available over-the-counter. You'll need a prescription from either an NHS specialist service or a private UK-licensed prescriber, following a clinical assessment to confirm suitability based on your weight, health conditions, and medical history.
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.