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
Do You Qualify for Mounjaro in the UK?
Mounjaro (tirzepatide) is available in the UK through both NHS specialist services and private prescribing, but eligibility depends on specific health criteria. This guide explains who qualifies, how NHS assessment works, and what you need to know about accessing this prescription-only weight management injection through different routes.
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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.
UK Eligibility Criteria for Mounjaro
To qualify for Mounjaro in the UK, you must meet specific BMI and health-related thresholds. General eligibility includes a BMI of 30 kg/m² or above, or a BMI of 27–29.9 kg/m² if you have at least one weight-related health condition.
Weight-related conditions recognised by NHS guidance include type 2 diabetes, prediabetes, high blood pressure, abnormal blood fats (dyslipidaemia), obstructive sleep apnoea, and a history of cardiovascular disease such as heart attack or stroke.
For adults of South Asian, Chinese, Black African, or Black Caribbean heritage, lower BMI thresholds apply — eligibility may start at BMI 27.5 or above because these groups face significantly higher cardiovascular and metabolic risk at lower BMI levels. You can check your personal BMI using our free BMI calculator to see where you stand against these thresholds.
You must be 18 or over, not pregnant, not breastfeeding, and have no allergy to tirzepatide. Your prescriber will also assess your overall health history during a clinical evaluation.
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 Access vs Private Route
NHS access: Mounjaro is approved by NICE for use within NHS specialist tier 3 weight management services. You typically need a referral from your GP to a specialist service in your region, though availability varies significantly by area and waiting lists can extend several months or longer.
Private access: You can obtain a prescription through GPhC-registered online pharmacies following a remote clinical assessment with a UK-licensed prescriber. This route does not require NHS referral and prescriptions are issued based on individual eligibility assessment. With our GLP-1 weight loss calculator, you can estimate potential outcomes at different Mounjaro doses to discuss with your prescriber.
Both routes require a prescription — Mounjaro is not available over the counter. Your prescriber will confirm that dose titration, from 2.5 mg up to your target maintenance dose, is appropriate for your health profile.
- 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 to qualify for Mounjaro in the UK?
You typically need a BMI of 30 or above, or 27–29.9 with weight-related health conditions like type 2 diabetes, high blood pressure, or sleep apnoea. For South Asian, Chinese, Black African, or Caribbean heritage adults, lower thresholds apply — often 27.5 or above. Check your BMI using our free calculator.
Can I get Mounjaro through the NHS?
Yes. NICE has approved tirzepatide for NHS specialist tier 3 weight management services. You'll need a GP referral to your regional specialist service. Availability and waiting times vary by area — some regions have longer waiting lists than others.
What's the difference between NHS and private Mounjaro prescribing?
NHS access requires GP referral to a specialist weight management service and follows NICE criteria. Private access is through online clinical assessment with a licensed UK prescriber, without NHS referral. Both require a prescription; private options may be faster but involve cost.
Am I ineligible for Mounjaro?
You cannot take Mounjaro if you're under 18, pregnant, breastfeeding, or allergic to tirzepatide. Severe digestion problems or a personal/family history of certain thyroid conditions may also exclude you. Your prescriber will assess your full medical history.
Do I need to lose weight before qualifying for Mounjaro?
No. Eligibility is based on your current BMI and health conditions — not on previous weight loss attempts. However, Mounjaro works best alongside reduced-calorie diet and increased physical activity, not instead of lifestyle changes.
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.