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
What Is The Criteria For Mounjaro in the UK?
Mounjaro (tirzepatide) is a prescription-only weight management injection that may help adults with excess weight. But not everyone is eligible — the UK has specific criteria based on your BMI and health conditions. Understanding these requirements helps you know whether to discuss Mounjaro with your GP. Your eligibility depends on your weight, height, and whether you have weight-related health conditions. Use our free BMI calculator above to check your current BMI instantly, then read on to see if you meet the clinical criteria.
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.
UK Eligibility Criteria for Mounjaro
You may be eligible for Mounjaro prescription in the UK if you meet one of these criteria:
- BMI of 30 kg/m² or above (regardless of health conditions)
- BMI of 27–29.9 kg/m² and at least one weight-related health condition
Weight-related health conditions that may qualify include type 2 diabetes, prediabetes, high blood pressure (hypertension), abnormal blood fats (dyslipidaemia), obstructive sleep apnoea, and a history of heart attack, stroke, or cardiovascular disease.
For people of South Asian, Chinese, Black African, or Black Caribbean heritage, the NHS recommends lower thresholds due to higher health risks at lower BMI levels. Your GP or prescriber can assess your individual eligibility based on your personal health profile and medical history.
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.
Who Cannot Take Mounjaro
Mounjaro is not suitable for everyone. You should not take Mounjaro if you are under 18 years old, pregnant, planning pregnancy, or breastfeeding. If you have a severe allergy to tirzepatide or any ingredients in the KwikPen device, it is not appropriate for you.
Certain medical conditions may also mean Mounjaro is unsuitable, including severe gastroparesis or serious digestion problems. Your GP or a licensed prescriber will assess your full medical history before offering Mounjaro as an option, ensuring it is safe and appropriate for your individual circumstances.
- 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 know if my BMI qualifies me for Mounjaro?
Calculate your BMI using our free tool on this page — enter your height and current weight in stone and kg. If your BMI is 30 or above, you generally qualify. If it's 27–29.9 and you have a weight-related health condition (like diabetes, high blood pressure, or sleep apnoea), you may also be eligible. Your GP can confirm.
What counts as a weight-related health condition for Mounjaro eligibility?
Eligible conditions include type 2 diabetes, prediabetes, high blood pressure, abnormal cholesterol levels, obstructive sleep apnoea, and previous heart attack or stroke. Speak to your GP about your specific health conditions — they'll assess whether they meet the criteria for Mounjaro prescription.
Can I get Mounjaro on the NHS or do I need to pay privately?
Mounjaro is available through NHS specialist tier 3 weight management services, but access is limited and varies by region. You may face long waiting lists. Private access is also available through UK-licensed prescribers and GPhC-registered online pharmacies, though this involves a cost.
How is Mounjaro different from Wegovy if they're both weight loss injections?
Mounjaro (tirzepatide) is a dual GIP and GLP-1 receptor agonist, while Wegovy (semaglutide) is a GLP-1 agonist only. Mounjaro uses two hormone pathways; Wegovy uses one. Both are prescription-only, but they have different mechanisms, doses, and trial data — your prescriber will assess which suits you.
What happens if I don't meet the criteria — can my GP prescribe Mounjaro anyway?
Mounjaro is licensed for specific eligibility criteria, and prescribers are expected to follow NICE guidance. If you don't meet the criteria, your GP may suggest other weight management options or refer you to a specialist tier 3 service for a full assessment. Always discuss your options with your healthcare provider. ```
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.