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 to Apply for Mounjaro on the NHS
If you're considering weight loss medication in the UK, you may have heard of Mounjaro (tirzepatide) and wondered how to access it through the NHS. The process involves referral to a specialist weight management service, clinical assessment, and eligibility checks. This guide explains how NHS Mounjaro access works, how it compares to Wegovy, and what to expect at each stage. Use our free BMI calculator above to check if you might meet the initial eligibility criteria.
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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.
NHS Access and Mounjaro vs Wegovy Comparison
To access Mounjaro through the NHS, you must be referred to a tier 3 specialist weight management service by your GP. These services are funded regionally and availability varies significantly across the UK. NICE (National Institute for Health and Care Excellence) has approved tirzepatide (Mounjaro) for use within NHS weight management services, but access depends on your local ICB (Integrated Care Board) funding and the waiting list capacity in your area.
Mounjaro vs Wegovy on the NHS: Both medications may be offered through NHS specialist services. Mounjaro is a dual GIP and GLP-1 receptor agonist, while Wegovy (semaglutide) is a GLP-1 agonist only. In clinical trials, Mounjaro showed average weight loss of approximately 15–21% of body weight, compared to Wegovy's approximately 15%. The choice between them depends on your individual health profile and prescriber recommendation. Your prescriber will assess which is more suitable during your specialist appointment. Both require a KwikPen (Mounjaro) or auto-injection pen (Wegovy) and are dosed weekly.
- Mounjaro: 2.5 mg to 15 mg once weekly (4-week dose escalation schedule)
- Wegovy: 0.25 mg to 2.4 mg once weekly (with dose increases every 1–2 weeks)
- Both require reduced-calorie diet and increased physical activity alongside medication
- Individual results vary significantly
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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 Eligibility and What to Expect
To be eligible for Mounjaro or Wegovy on the NHS, you must have a BMI of 30 kg/m² or above, or a BMI of 27–29.9 with at least one weight-related health condition (type 2 diabetes, prediabetes, high blood pressure, or sleep apnoea). South Asian, Chinese, Black African, and Black Caribbean adults may have access from a BMI of 27.5 or above due to higher health risks at lower weights. Once referred to a specialist service, expect a clinical assessment covering your medical history, previous weight loss attempts, and current medications. Treatment typically begins at the lowest dose with escalation over several weeks. Waiting times for NHS specialist services can be several months to over a year in many areas.
If NHS waiting times are lengthy, you may consider private prescription access through licensed UK prescribers, though this involves upfront costs. Calculate your potential weight loss using our GLP-1 weight loss calculator to understand realistic outcomes alongside your GP or 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.
How long does it take to get Mounjaro on the NHS?
Waiting times vary by region. NHS specialist weight management services typically have waiting lists of 3–12 months or longer, depending on your local ICB. Once referred by your GP, you'll be assessed, and if approved, treatment usually begins within 2–4 weeks of your specialist appointment. Fast-track access is sometimes available for patients with serious weight-related complications.
What's the difference between Mounjaro and Wegovy?
Mounjaro (tirzepatide) is a dual GIP and GLP-1 receptor agonist; Wegovy (semaglutide) is GLP-1 only. Clinical trials showed Mounjaro achieved average weight loss of 15–21% and Wegovy approximately 15%. Both are once-weekly injections. The choice depends on individual suitability, prescriber recommendation, and availability through your NHS specialist service.
Do I need to have tried other weight loss methods first?
Yes, NHS specialist services typically require evidence of previous structured weight loss attempts, such as referral to a dietitian, attendance at weight management programmes, or use of lower-calorie diets under supervision. This demonstrates commitment and helps the specialist assess whether medication is appropriate for your situation.
What happens if I don't meet NHS eligibility criteria?
If your BMI is below the NHS threshold or you don't have qualifying comorbidities, you may not be eligible through the NHS. However, private prescription routes are available through licensed UK prescribers following an online clinical assessment. Private costs typically range from £129–£320 per month depending on dose and provider.
Can I switch from Wegovy to Mounjaro on the NHS?
Yes, it's possible to switch between medications, but this requires discussion with your specialist prescriber. There is no official conversion chart — your prescriber will assess the appropriate dose and timing of any switch. Both medications work similarly but have different mechanisms, so the change should be managed carefully and monitored.
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.