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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Who Qualifies for Mounjaro on the NHS?
Mounjaro (tirzepatide) is available through the NHS for adults meeting specific eligibility criteria, though access varies significantly by region. In the UK, you may qualify if you have a BMI of 30 or above, or a BMI of 27–29.9 with weight-related health conditions. Lower thresholds apply for South Asian, Chinese, Black African, and Black Caribbean adults. Access is through specialist tier 3 weight management services, typically following a referral from your GP. This guide explains NHS eligibility, how the application process works, and what to expect when accessing Mounjaro through the UK health system.
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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 Criteria for Mounjaro
To qualify for Mounjaro through the NHS, you must meet specific weight and health criteria. You may be eligible if:
- You have a BMI of 30 kg/m² or above (obesity), OR
- You have a BMI of 27–29.9 kg/m² (overweight) with at least one weight-related health condition
Weight-related health conditions that may qualify include: type 2 diabetes or prediabetes, high blood pressure, abnormal blood fats (dyslipidaemia), obstructive sleep apnoea, or a history of heart attack or stroke.
For adults of South Asian, Chinese, Black African, or Black Caribbean heritage, the NHS recommends lower BMI thresholds — eligibility may start at BMI 27.5 or above, as these groups face higher cardiovascular and diabetes risk at lower BMI levels.
You cannot access NHS Mounjaro if you are under 18, pregnant, breastfeeding, or allergic to tirzepatide. Use our free BMI calculator above to check where you fall in the eligibility range.
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.
Accessing Mounjaro: NHS vs Private Routes
The NHS prescribes Mounjaro through specialist tier 3 weight management services — you cannot get it from your standard GP practice. Referral pathways and waiting times vary significantly by region (integrated care board). In some areas, NHS access involves substantial waiting lists, sometimes 12 months or longer.
Many UK adults access Mounjaro privately through GPhC-registered online prescribing services following a clinical assessment. Private costs range from approximately £129 to £320 per month depending on your dose — the Mounjaro KwikPen device comes with 4 pre-filled doses per pen (4 weeks' supply). Whether NHS or private, all access requires a prescription from a UK-licensed prescriber who confirms you meet eligibility 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.
How do I get referred for Mounjaro on the NHS?
Start by speaking to your GP about weight management support. Your GP can assess whether referral to a tier 3 specialist weight management service is appropriate. Not all GPs routinely refer — you may need to specifically request referral. Once referred, the specialist team will conduct a full assessment including blood tests, height and weight measurements, and health history before deciding if Mounjaro is suitable. Regional waiting lists vary considerably.
What's the difference between NHS and private Mounjaro access?
NHS Mounjaro is free at point of use but requires GP referral and specialist assessment through tier 3 services, with significant regional variation and potential waiting lists. Private Mounjaro requires an online consultation with a UK-licensed prescriber and costs £129–£320 monthly depending on dose, but is available without NHS referral and typically faster access. Both routes require prescription and clinical assessment.
Can I get Mounjaro from my standard GP?
No. Mounjaro is a specialist weight management medicine prescribed only through tier 3 or 4 NHS weight management services, not standard GP practices. Your GP can refer you to these specialist services, but cannot prescribe Mounjaro directly. This is why NHS access often involves waiting lists and specialist appointments rather than quick GP prescriptions.
What happens if my BMI is 27–29.9 — can I still qualify?
Yes, you may qualify if your BMI is 27–29.9 AND you have at least one weight-related health condition such as type 2 diabetes, prediabetes, high blood pressure, sleep apnoea, or cardiovascular disease. Your prescriber will assess your overall health profile, not just BMI alone. Lower thresholds apply for certain ethnic backgrounds — check with your GP if you have South Asian, Black African, or similar heritage.
How long does the NHS Mounjaro process take?
From GP referral to first prescription typically takes several weeks to months depending on your region. Some areas have 3–6 month waits, others significantly longer. Private routes are usually faster, often 1–2 weeks from consultation to prescription. The actual dose titration (gradually increasing from 2.5mg to your target dose) takes at least 5 months 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.