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 I Qualify For Mounjaro in the UK?
Whether you qualify for Mounjaro (tirzepatide) in the UK depends on your BMI, health conditions, and how you choose to access it — either through the NHS or private prescription routes. This guide explains the eligibility criteria, what happens during assessment, and the differences between NHS and private access. Use our free BMI calculator above to check your starting point, then read on to understand your options.
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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 Mounjaro Eligibility Criteria and Access Routes
In the UK, Mounjaro is a prescription-only medicine, meaning you cannot simply purchase it without a clinical assessment. NHS eligibility typically requires a BMI of 30 kg/m² or above, or 27–29.9 kg/m² with at least one weight-related health condition (such as type 2 diabetes, high blood pressure, or sleep apnoea). For adults of South Asian, Chinese, Black African, or Black Caribbean heritage, lower thresholds apply — eligibility may begin at BMI 27.5 or above due to higher cardiovascular risk at lower BMI levels. Private prescription routes may assess similar criteria but availability is broader; you don't need an NHS referral and can be assessed online by a UK-licensed prescriber. Age restrictions apply: Mounjaro is only prescribed to adults aged 18 and over. Pregnancy, plans to become pregnant, and breastfeeding are contraindications. Using our GLP-1 weight loss calculator can help you estimate potential outcomes if you're considering Mounjaro at different doses.
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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: Costs, Timelines, and What to Expect
NHS route: If eligible, you are referred by your GP to a specialist tier 3 weight management service. This route is free but waiting lists can be months to years depending on your region (integrated care board). Private route: An online consultation with a UK-licensed prescriber costs around £20–£40; if approved, Mounjaro costs approximately £129–£250 per month depending on dose — a KwikPen contains 4 weeks of injections. Private prescriptions are dispensed by GPhC-registered pharmacies. Both routes require a clinical assessment before prescription, and both require that you have capacity for lifestyle changes (diet and activity) alongside medication. Track your progress with our free progress tracker once you begin treatment.
- 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 on the NHS?
NHS Mounjaro is typically prescribed for adults with BMI 30 or above, or BMI 27–29.9 with weight-related health conditions (diabetes, hypertension, sleep apnoea). For South Asian, Chinese, Black African, and Black Caribbean adults, lower thresholds apply (from BMI 27.5). Ethnicity-adjusted thresholds reflect higher cardiovascular risk in these groups.
Can I get Mounjaro on the NHS if I don't meet the BMI threshold?
Yes, if you have significant weight-related health conditions even at lower BMI — your GP can refer you to specialist services for assessment. However, NHS availability varies by region; some areas have long waiting lists or limited access. Private prescription may be faster if you meet eligibility criteria.
How long does it take to get Mounjaro on the NHS?
Waiting times vary significantly by region. Many areas have waiting lists of 6 months to 2+ years for tier 3 specialist weight management services. Private assessment is typically faster — often within days — but at a cost. Check with your local integrated care board for current timescales in your area.
What happens during a Mounjaro eligibility assessment?
A prescriber (NHS or private) will review your medical history, current medications, BMI, weight-related conditions, and ability to commit to lifestyle changes. They may check blood pressure, blood sugar, and kidney function. You'll discuss how Mounjaro works and potential side effects. This process confirms that Mounjaro is safe and appropriate for you personally.
How much does Mounjaro cost privately in the UK?
Private Mounjaro costs approximately £129–£250 per month depending on dose (5 mg to 15 mg). A KwikPen contains 4 weekly injections (one month supply). Prices vary slightly between GPhC-registered pharmacies. Online consultations with prescribers typically cost £20–£40. Always compare total costs including consultation fees before committing.
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.