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 Qualifies for Mounjaro in the UK?
Mounjaro (tirzepatide) is a prescription-only weight management injection available in the UK through NHS specialist services and private online prescribing. Eligibility depends on your BMI, health conditions, and age. The NHS has specific qualifications you must meet, and access typically goes through tier 3 weight management services. Understanding your eligibility is the first step towards exploring whether this medication might support your weight management journey. Our free BMI calculator above can help you determine where your weight sits relative to NHS thresholds.
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.
NHS Eligibility Criteria for Mounjaro in the UK
The NHS approves Mounjaro (tirzepatide) for adults who meet specific criteria. You may qualify if you have a BMI of 30 kg/m² or above (obesity), or a BMI of 27–29.9 kg/m² (overweight) with at least one weight-related health condition. Weight-related conditions that qualify include type 2 diabetes, prediabetes, high blood pressure, abnormal blood fats, obstructive sleep apnoea, or a history of heart attack or stroke. For adults of South Asian, Chinese, Black African, or Black Caribbean heritage, lower BMI thresholds apply — you may qualify at BMI 27.5 or above, reflecting higher cardiovascular risk in these populations. You must be 18 years or older. NICE has approved tirzepatide as part of the NHS weight management pathway for eligible adults, though regional availability varies. Access is through specialist tier 3 or tier 4 weight management services, not routine GP prescription.
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 Route vs Private Prescribing
NHS route: You'll need a GP referral to a local specialist weight management service, where a multidisciplinary team assesses your suitability. Waiting times vary significantly by region and can extend several months in high-demand areas. Private route: UK-licensed prescribers offer online consultations for Mounjaro, with prescription dispensed by GPhC-registered pharmacies if clinically appropriate — no NHS referral needed. Private access is typically faster but involves direct costs. Both routes require a thorough clinical assessment; you cannot self-prescribe Mounjaro. Our GLP-1 weight loss calculator can help you explore projected weight loss outcomes based on your starting weight and dose.
- 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.
Do I need to be obese to qualify for Mounjaro on the NHS?
No. You can qualify with a BMI of 27–29.9 (overweight) if you have a weight-related health condition such as type 2 diabetes, high blood pressure, or sleep apnoea. For certain ethnic backgrounds, thresholds are lower. A BMI of 30 or above (obesity) qualifies without requiring additional conditions.
How long does it take to get Mounjaro through the NHS?
Waiting times vary by region and local ICB (Integrated Care Board). Some areas have waits of several months; others longer. Tier 3 specialist services are often oversubscribed. Private prescribing typically offers faster access if you meet clinical criteria, usually within days to weeks.
What health conditions count as "weight-related" for Mounjaro eligibility?
Type 2 diabetes, prediabetes, high blood pressure (hypertension), abnormal blood fats (dyslipidaemia), obstructive sleep apnoea, and cardiovascular disease (history of heart attack or stroke) all qualify. Your GP or specialist can assess whether your specific condition meets criteria.
Are there age restrictions for Mounjaro in the UK?
Yes, Mounjaro is approved for adults aged 18 years and over only. It is not licensed for children or teenagers. Under-18s with excess weight are managed through different NHS pathways and specialist paediatric services.
Can my GP prescribe Mounjaro directly, or do I need a specialist referral?
Your GP cannot routinely prescribe Mounjaro. You need a referral to a specialist tier 3 weight management service for NHS access, or a private online consultation with a UK-licensed prescriber. Both require clinical assessment, not just GP request.
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.