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
Free tracker included with every download this week
Who Is Eligible for Mounjaro in the UK?
Eligibility for Mounjaro in the UK depends on your BMI, health conditions, and whether you access it through the NHS or privately. Mounjaro (tirzepatide) is a prescription-only GLP-1 and GIP receptor agonist approved for weight management in UK adults. Your eligibility is assessed individually by a healthcare professional following a clinical evaluation. This guide explains the BMI thresholds, health criteria, and access routes available to you.
10,000+ calculations today · NHS-aligned thresholds · 100% free
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.
BMI Thresholds and Health Conditions for Mounjaro
You may be eligible for Mounjaro if you meet one of these criteria:
- BMI of 30 or above (obese category), OR
- BMI of 27–29.9 (overweight) with at least one weight-related health condition
Weight-related health conditions that may qualify include type 2 diabetes, prediabetes, high blood pressure, abnormal blood fat levels, 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 because these groups face higher cardiovascular and metabolic risks at lower BMIs. Calculate your BMI using our free BMI calculator above to check where you fall. You cannot take Mounjaro if you are under 18, pregnant, breastfeeding, or have a known allergy to tirzepatide.
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 Access Routes
NHS access: Available through specialist tier 3 weight management services following a GP referral. NICE has approved tirzepatide for NHS use, but access varies significantly by region and waiting lists can be lengthy. Private access: Available without NHS referral through GPhC-registered online pharmacies following a remote clinical assessment with a UK-licensed prescriber. The online consultation assesses your medical history, current medications, and suitability for tirzepatide. Costs typically range from £129–£280 per month depending on your dose. A prescriber will evaluate whether Mounjaro is appropriate for you — it is not available to everyone, and individual health circumstances determine eligibility.
- 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 BMI do I need for Mounjaro eligibility?
You need a BMI of 30 or above, or a BMI of 27–29.9 with a weight-related health condition like type 2 diabetes or high blood pressure. If you're of South Asian, Chinese, Black African, or Black Caribbean heritage, lower thresholds may apply (BMI 27.5+). Use our free BMI calculator to check yours instantly.
How much does Mounjaro cost on the NHS?
Mounjaro is free on the NHS if prescribed through specialist weight management services, but access requires GP referral and availability varies significantly by region. Some areas have waiting lists of many months or years for specialist services.
What does private Mounjaro cost in the UK?
Private Mounjaro prescriptions typically cost £129–£280 per month depending on your dose. Starting doses (2.5 mg) are usually cheaper; maximum doses (15 mg) are more expensive. Costs may vary between providers — always check before committing.
What happens in an online Mounjaro consultation?
A UK-licensed prescriber will review your medical history, current medications, weight, BMI, and health conditions. They'll assess whether Mounjaro is safe and suitable for you. If approved, a prescription is issued and dispensed by a GPhC-registered pharmacy. If not suitable, they'll explain why and may suggest alternatives.
Can I get Mounjaro without a prescription?
No. Mounjaro is a prescription-only medicine in the UK. You cannot access it without a valid prescription from a licensed prescriber, whether through the NHS or privately. Always use legitimate, regulated services for prescriptions.
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.