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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How To Qualify For Mounjaro in the UK
Mounjaro (tirzepatide) is a prescription-only weight management injection available in the UK, but not everyone is eligible. Whether you can access it depends on your BMI, any weight-related health conditions you have, and your ethnic background — as the NHS recognises that some groups face higher health risks at lower weights. This guide explains the exact eligibility criteria and how to check whether you qualify for this dual GLP-1 and GIP receptor agonist medication.
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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.
Mounjaro Eligibility Criteria — UK Standard Thresholds
To qualify for Mounjaro in the UK, you must meet one of these criteria:
- BMI of 30 or above (obesity classification), regardless of health conditions
- BMI of 27 to 29.9 (overweight range) with at least one weight-related health condition
Weight-related health conditions that may qualify you include type 2 diabetes, prediabetes, high blood pressure, abnormal blood cholesterol, obstructive sleep apnoea, or a history of heart attack or stroke. Use our free BMI calculator above to check your personal BMI instantly — then cross-reference your result with these thresholds. If your BMI is in the eligible range and you have a relevant health condition, you may be a candidate for prescription treatment.
It's important to note that meeting these criteria doesn't assures a prescription — a healthcare professional must assess whether Mounjaro is appropriate for your individual circumstances, including your medical history and any medications you currently take.
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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.
Lower BMI Thresholds for Certain Ethnic Groups
The NHS recognises that people of South Asian, Chinese, Black African, or Black Caribbean heritage have a higher risk of type 2 diabetes and heart disease at lower BMI levels. Because of this, lower BMI thresholds apply if you belong to one of these groups:
- BMI of 27.5 or above (instead of 30)
- BMI of 23 to 27.4 with weight-related health conditions
This adjustment reflects clinical evidence that health risks emerge earlier in these populations. If you're unsure whether adjusted thresholds apply to you, mention your ethnic background when discussing Mounjaro eligibility with your GP or a licensed prescriber. They will assess your individual risk and determine whether you meet the criteria for this medication.
- 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.
Can I get Mounjaro on the NHS?
Yes, Mounjaro (tirzepatide) is approved by NICE for use within the NHS for weight management. However, access is through specialist tier 3 weight management services, not standard GP prescribing. You typically need a GP referral, and waiting times vary significantly by region. Many areas have long waiting lists.
What if I don't meet the BMI threshold but have serious health conditions?
BMI thresholds are guidelines, not absolute rules. If you have significant weight-related health conditions like type 2 diabetes or cardiovascular disease, your GP or specialist may consider you even if your BMI is slightly below the standard threshold. Always discuss your individual circumstances with your healthcare provider.
How do I know my BMI?
Calculate your BMI using our free BMI calculator on this page — just enter your weight in kg or stone, and your height in cm or feet and inches. Your result will show which NHS category you fall into and whether you meet Mounjaro eligibility thresholds.
Are there any age restrictions for Mounjaro?
Yes, Mounjaro is only licensed for adults aged 18 and over. It is not approved for use in children or teenagers, and it should not be used during pregnancy or while breastfeeding.
Can I get Mounjaro privately if I don't qualify through the NHS?
Yes. Private access to Mounjaro is available through GPhC-registered online pharmacies following a clinical assessment by a UK-licensed prescriber. You do not need an NHS referral, but you will need a valid prescription, and costs vary by provider and dose (typically £129–£320+ monthly).
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.