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 Mounjaro Criteria and Cost in the UK
Mounjaro (tirzepatide) is available in the UK through both NHS specialist services and private prescription routes, but access, criteria, and costs differ significantly. This guide explains NHS eligibility requirements, private costs, and how to understand your options for accessing this weight management medication. Whether you're eligible through the NHS or considering private prescription, knowing the criteria and realistic costs helps you make an informed decision.
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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.
Understanding Mounjaro Eligibility and Costs
NHS Mounjaro eligibility is assessed by specialist tier 3 or tier 4 weight management services following GP referral. You may qualify if you have a BMI of 30 kg/m² or above, or a BMI of 27–29.9 with weight-related health conditions such as type 2 diabetes, prediabetes, high blood pressure, sleep apnoea, or cardiovascular disease. For adults of South Asian, Chinese, Black African, or Black Caribbean heritage, lower thresholds apply (BMI 27.5 or above). NICE has approved tirzepatide for NHS use, but regional availability varies significantly — some areas have lengthy waiting lists or limited access.
Private prescription costs range from approximately £129 to £320 per month depending on your Mounjaro dose. The 2.5 mg starting dose is typically the least expensive, while higher maintenance doses (10 mg, 15 mg) cost more. These costs are not NHS-funded when prescribed privately, meaning you pay the full amount out of pocket. Private prescribing requires an online clinical assessment with a UK-licensed prescriber to confirm suitability before dispensing.
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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 Routes and What to Expect
The NHS route requires referral from your GP to a specialist weight management service, which involves assessment, waiting periods (sometimes months), and then prescription if approved — at no medication cost to you. The private route is faster: you complete an online consultation, a UK-licensed prescriber assesses your eligibility, and if approved, your prescription is dispensed by a GPhC-registered pharmacy within days. Private access does not require NHS referral but involves out-of-pocket medication costs.
Use our free BMI calculator above to check your current BMI and understand which eligibility bracket you fall into. Regardless of route, Mounjaro is most effective when combined with reduced-calorie diet and increased physical activity. Your prescriber will monitor side effects and adjust your dose over weeks, titrating from 2.5 mg upwards as tolerated. Try our GLP-1 weight loss calculator to estimate potential weight loss outcomes at different doses.
- 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 is the exact BMI threshold for NHS Mounjaro in the UK?
The NHS standard threshold is BMI 30 kg/m² or above, or BMI 27–29.9 with weight-related health conditions (diabetes, high blood pressure, sleep apnoea, cardiovascular disease). Adults of South Asian, Chinese, Black African, or Black Caribbean heritage may qualify at BMI 27.5 or above due to higher metabolic health risks at lower BMI levels.
How much does Mounjaro cost privately in the UK?
Private Mounjaro costs approximately £129–£320 per month depending on dose. Starting dose (2.5 mg) is typically cheaper; maintenance doses (10 mg, 15 mg) cost more. Costs vary slightly between providers but are out-of-pocket and not NHS-funded when prescribed privately.
How long is the NHS waiting list for Mounjaro?
NHS waiting times vary significantly by region and local ICB (Integrated Care Board). Some areas have waits of months to years; others may have shorter waits or limited availability. Contact your local weight management service or ask your GP about specific timescales in your area.
Do I need a GP referral for private Mounjaro prescription?
No. Private prescription requires an online clinical assessment with a UK-licensed prescriber, but does not require NHS GP referral. You can access private prescribing directly without going through the NHS system, though private costs apply.
What happens during an online Mounjaro assessment?
An online assessment reviews your BMI, weight-related health conditions, current medications, medical history, and any contraindications. A UK-licensed prescriber decides if Mounjaro is appropriate for you. If approved, your prescription is issued and dispensed by a GPhC-registered pharmacy, usually within 2–5 working days.
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.