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 Weight Loss Through the NHS in the UK
Mounjaro (tirzepatide) is a prescription-only weight loss injection now available through NHS specialist services in the UK. This dual GIP and GLP-1 receptor agonist works by reducing appetite and supporting feeling fuller after meals. Access through the NHS requires referral to a tier 3 weight management service and meeting specific eligibility criteria. We'll explain how NHS prescribing works, what you need to know about tirzepatide, and how the NHS approach compares to private options available in the UK.
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Calculate Your BMI Instantly
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 Tier 3 Weight Management Services
NICE (National Institute for Health and Care Excellence) approved tirzepatide in 2024 for use within NHS specialist weight management services. However, NHS access is not through your GP for routine prescription — instead, you must be referred to a tier 3 or tier 4 specialist multidisciplinary weight management service.
- Eligible if: BMI ≥30 kg/m² with weight-related health conditions, or BMI ≥35 regardless of comorbidities
- Lower thresholds apply to adults of South Asian, Chinese, Black African, or Black Caribbean heritage (BMI ≥27.5)
- Weight-related conditions: type 2 diabetes, prediabetes, hypertension, dyslipidaemia, obstructive sleep apnoea, or cardiovascular disease history
- Regional variation: Availability differs significantly by integrated care board (ICB) — some regions have extensive services, others have limited provision or long waiting lists
Your GP can refer you to your local tier 3 service. Use our free BMI calculator above to check your starting point, and our GLP-1 weight loss calculator to see projected outcomes with tirzepatide at different doses.
Clinically BackedWeight Loss
No appointments. No waiting rooms. Just care — from a UK-regulated online pharmacy.
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 Routes for Mounjaro in the UK
NHS route: Free prescription through tier 3 services, but referral required and waiting lists can span months or years depending on your region. Specialist monitoring included. Private route: Available through GPhC-registered online prescribing services following an online clinical assessment — faster access, no waiting list, but costs approximately £129–£320 monthly depending on dose. Both routes require a prescription from a UK-licensed prescriber. Neither route assures weight loss — clinical trials showed average weight loss of 15–21% body weight alongside a reduced-calorie diet and increased physical activity. Track your progress using our free progress tracker whether you access Mounjaro through NHS or private channels.
- 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 do I get Mounjaro prescribed on the NHS?
Ask your GP for a referral to your local tier 3 specialist weight management service. Your GP will assess whether referral is appropriate based on your BMI and health conditions. The specialist service will then conduct a full assessment before prescribing. Waiting times vary significantly by region — contact your local ICB for current timescales in your area.
What BMI do I need to qualify for NHS Mounjaro?
Generally, BMI ≥30 with weight-related health conditions, or BMI ≥35 without comorbidities. If you're of South Asian, Chinese, Black African, or Black Caribbean heritage, lower thresholds apply — eligibility may start at BMI ≥27.5. Use our free BMI calculator to check your current BMI.
How long does it take to get Mounjaro on the NHS?
Timescales vary by region. Some tier 3 services have waiting lists of several months; others may take 1–2 years. This depends on local funding, demand, and service capacity. Contact your local weight management service directly for realistic timescales in your area.
Is Mounjaro free on the NHS?
Yes, if prescribed through an NHS tier 3 service, Mounjaro is free on prescription. However, accessing tier 3 services requires GP referral and meeting eligibility criteria. Regional variation means some areas have better access than others.
What's the difference between NHS and private Mounjaro?
NHS Mounjaro is free but involves waiting lists and requires specialist referral. Private Mounjaro is faster (no waiting list) but costs £129–£320 monthly. Both require prescriptions from UK-licensed prescribers. Results and monitoring are similar — individual outcomes vary regardless of route.
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.