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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NHS Eligibility for Mounjaro — Who Can Get It?
Mounjaro (tirzepatide) is available through the NHS for eligible adults with obesity or overweight with health complications. However, NHS access is limited to specialist tier 3 weight management services, and eligibility varies significantly by region. This guide explains NICE guidance on Mounjaro eligibility, how the NHS prescribing pathway works, and what to expect if you're referred to a specialist service. Individual circumstances differ, so your GP can advise whether you might be suitable for assessment.
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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 Criteria for Mounjaro
The NICE guidelines approve tirzepatide (Mounjaro) for NHS use in adults who meet specific BMI and health criteria. You may be eligible if you have a BMI of 30 or above, or a BMI of 27–29.9 with at least one weight-related health condition. Weight-related conditions that may qualify include type 2 diabetes or prediabetes, high blood pressure, abnormal blood cholesterol, obstructive sleep apnoea, or a history of cardiovascular disease.
For adults of South Asian, Chinese, Black African, or Black Caribbean heritage, the NHS recognises lower risk thresholds — you may be eligible at a BMI of 27.5 or above without additional health conditions, as these groups face higher metabolic risk at lower weights.
You must also be aged 18 or over, not pregnant or planning pregnancy, and not have severe gastroparesis or other contraindications. Your GP will assess your individual circumstances before any referral to specialist services.
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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.
Accessing Mounjaro Through NHS Specialist Services
Mounjaro is not routinely prescribed in primary care — access is through tier 3 specialist weight management services, available in most NHS regions but with significant variation in provision and waiting times. Your GP can refer you to your local service if they believe you meet the criteria, but referral does not assures prescription.
The specialist team will conduct a full assessment including blood tests, cardiovascular evaluation, and confirmation that you've engaged with lifestyle changes. If approved, you'll receive the Mounjaro KwikPen with dose titration starting at 2.5 mg weekly, increasing every 4 weeks if tolerated. Use our GLP-1 weight loss calculator to see projected outcomes at different doses alongside your lifestyle plan.
NHS vs private access: Private prescribing through regulated online services bypasses the waiting list, typically delivering within 1–2 weeks following an online clinical assessment. Costs vary but are substantially higher than NHS provision. NHS access is free but may involve months-long waiting lists in some regions. Many eligible patients currently use private services due to NHS capacity constraints, though costs can range from £129–£320 monthly depending on your dose and provider.
- 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.
What's the minimum BMI to get Mounjaro on the NHS?
The NICE-approved threshold is BMI 30 or above. If your BMI is 27–29.9, you must have a weight-related health condition such as type 2 diabetes, high blood pressure, or cardiovascular disease. For South Asian, Chinese, Black African, or Black Caribbean adults, the threshold is lower at BMI 27.5 or above. Use our BMI calculator to check your personal BMI quickly.
How long is the NHS waiting list for Mounjaro?
Waiting times vary dramatically by region and local NHS capacity. Some specialist services have waiting lists of 6–12 months; others may be longer due to high demand. There is no national standard. Contact your local integrated care board (ICB) or ask your GP about current waiting times in your area.
Can my GP prescribe Mounjaro directly, or do I need a specialist referral?
Mounjaro is only prescribed through NHS tier 3 specialist weight management services, not by GPs in primary care. Your GP can refer you if they believe you're eligible, but the prescription decision rests with the specialist multidisciplinary team after full assessment and blood tests.
What happens during the specialist assessment for Mounjaro?
The specialist team will review your weight history, health conditions, previous weight loss attempts, blood tests (glucose, lipids, liver and kidney function), and cardiovascular risk. They'll confirm you've engaged with lifestyle support and assess suitability for tirzepatide before approval. The process typically takes several weeks.
Is Mounjaro tirzepatide the same as Wegovy or Ozempic?
Mounjaro (tirzepatide) and Wegovy (semaglutide) are both GLP-1 agonists approved for weight management, but tirzepatide is a dual GIP/GLP-1 agonist, making it mechanically different. Ozempic is semaglutide at a lower dose approved for diabetes, not weight loss. NHS policies differ between medications by region.
Ready to take control of your weight loss journey?
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