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 Access Mounjaro Through the NHS in the UK
Mounjaro (tirzepatide) is a prescription-only GLP-1 receptor agonist and GIP receptor agonist licensed in the UK for weight management in adults. Access through the NHS is available, but availability varies significantly by region and typically requires referral to specialist tier 3 weight management services. This guide explains NHS eligibility criteria, how the specialist pathway works, and how it compares to private access options 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.
NHS Eligibility and Specialist Services
In the UK, Mounjaro is available through NHS specialist weight management services (tier 3 or tier 4). You cannot typically obtain Mounjaro through a standard GP prescription — referral to a specialist multidisciplinary team is required. NHS eligibility for weight loss medication generally requires:
- A BMI of 30 kg/m² or above, OR
- A BMI of 27–29.9 kg/m² with at least one weight-related health condition (type 2 diabetes, prediabetes, high blood pressure, abnormal blood lipids, obstructive sleep apnoea, or cardiovascular disease)
- For adults of South Asian, Chinese, Black African, or Black Caribbean heritage, lower thresholds may apply (BMI 27.5 or above)
NICE (National Institute for Health and Care Excellence) has approved tirzepatide for use within NHS weight management services. However, regional variations are significant — not all NHS areas offer access to Mounjaro, and some regions prioritise Wegovy (semaglutide) or other GLP-1 medications. Waiting times for NHS specialist services can be substantial, often ranging from several months to over a year in many areas.
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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 vs Private Access in the UK
The NHS pathway involves referral from your GP to a specialist weight management service, which assesses suitability and prescribes medication alongside behaviour change support. Private access is available through GPhC-registered online pharmacies following an online clinical assessment with a UK-licensed prescriber — no NHS referral needed. Private Mounjaro costs approximately £129–£320 per month depending on dose, and is available without waiting lists. The NHS route is free at point of care if access is available in your area, but regional variation and waiting times remain significant barriers. Use our free BMI calculator above to check your eligibility, and discuss the NHS pathway with your GP if you meet the criteria.
- 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.
Can I get Mounjaro on the NHS in the UK?
Yes, Mounjaro is available through NHS specialist tier 3 weight management services, but only if you meet eligibility criteria and are referred by your GP. Availability varies by region, and waiting lists are often very long. Not all NHS areas currently offer tirzepatide access.
What BMI do I need to qualify for Mounjaro on the NHS?
Generally, a BMI of 30 or above, or 27–29.9 with a weight-related health condition. For South Asian, Chinese, Black African, or Black Caribbean adults, the threshold may be BMI 27.5 or above. Your GP can assess your individual circumstances.
How long does it take to access Mounjaro through the NHS?
Waiting times vary widely by region. Many NHS areas have waiting lists of several months to over a year for specialist weight management services. Some regions may not offer tirzepatide at all.
What's the difference between NHS and private Mounjaro access?
NHS access is free but involves referral, waiting lists, and regional variation. Private access requires payment (£129–£320/month) but is faster, available without referral, and accessible nationwide through online clinical assessments.
What does "tier 3" weight management service mean?
The NHS has a four-tier weight management pathway. Tier 3 is specialist multidisciplinary services — the level where prescription weight loss medications are typically initiated. Tier 1 is self-help, tier 2 is primary care, and tier 4 is bariatric surgery.
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.