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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Mounjaro GP Criteria — Who Can Get It on the NHS?
Mounjaro (tirzepatide) is a prescription-only weight management injection that may be prescribed in the UK through NHS specialist weight management services. Your eligibility depends on your BMI, health conditions, and individual circumstances. Understanding the NHS criteria helps you know whether to ask your GP for a referral to tier 3 or tier 4 weight management services. This guide covers NHS guidelines, NICE approval, and how the eligibility process works across the UK.
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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.
NHS Eligibility Criteria for Mounjaro
Mounjaro is approved by NICE (National Institute for Health and Care Excellence) for use within NHS specialist weight management services. To be considered for NHS tirzepatide, you must generally meet these criteria:
- BMI of 30 kg/m² or above (obesity), OR
- 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 (dyslipidaemia), obstructive sleep apnoea, or a history of heart attack or stroke. For adults of South Asian, Chinese, Black African, or Black Caribbean heritage, the NHS recommends lower thresholds — eligibility may start at BMI 27.5 or above, as these groups face higher cardiovascular and metabolic risk at lower BMI levels. Use our free BMI calculator above to check your personal BMI instantly and see where you fall within NHS categories.
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 vs Private Access Routes
NHS route: You must be referred by your GP to a tier 3 (specialist community) or tier 4 (tertiary) weight management service. Availability varies significantly by region — some areas have long waiting lists (months to years), whilst others may have limited provision. MHRA monitoring (Black Triangle ▼ status) means the NHS tracks safety data closely.
Private route: You can access Mounjaro through a GPhC-registered online pharmacy following a clinical assessment by a UK-licensed prescriber, without NHS referral. Eligibility criteria are similar, but the prescription process is faster. Costs typically range from £180–£300 per month depending on your dose and the provider.
- 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.
Will my GP automatically refer me for Mounjaro?
Not automatically. Your GP may refer you to specialist weight management services if you meet NHS criteria and have tried lifestyle changes. However, referral depends on your local commissioning and your GP's clinical judgement. Ask your GP about tier 3 weight management services in your area.
What's the difference between Mounjaro and Wegovy for NHS eligibility?
Both tirzepatide (Mounjaro) and semaglutide (Wegovy) have similar NHS eligibility criteria. Mounjaro is a dual GIP/GLP-1 agonist; Wegovy is GLP-1 only. Both require BMI 30+ or BMI 27–29.9 with a health condition. NHS availability and waiting times vary by region for each.
Can I get Mounjaro if I have type 2 diabetes?
Yes. Type 2 diabetes is a weight-related condition that qualifies you for consideration with a lower BMI threshold. If you have diabetes and a BMI of 27 or above, you may be eligible. Your GP or specialist can assess this based on your overall health picture.
How long does the NHS referral process take?
Waiting times vary widely by region and local commissioning. Some areas have waiting lists of 6–18 months. You can ask your GP how long the typical wait is in your local NHS integrated care board (ICB). Private access is faster if you wish to pursue that route.
What if I don't meet the BMI criteria — can I still get Mounjaro?
NHS prescribing generally follows NICE guidance based on BMI thresholds and health conditions. If you don't meet these, your GP may recommend lifestyle interventions first. Private prescribers have similar eligibility criteria but can assess your individual circumstances. Try our GLP-1 weight loss calculator to explore potential outcomes.
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.