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 — How to Access in the UK
If you're wondering whether you're eligible for Mounjaro in the UK, your GP or a licensed prescriber will assess you based on specific health criteria. Mounjaro (tirzepatide) is a prescription-only weight management injection, and access depends on your BMI, weight-related health conditions, and ethnicity-adjusted thresholds. This guide explains the eligibility criteria, how to access Mounjaro through the NHS or privately, and what to expect when consulting a healthcare professional about this treatment option.
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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.
Eligibility Criteria for Mounjaro in the UK
You may be eligible for Mounjaro 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 (dyslipidaemia), obstructive sleep apnoea, or a history of heart attack or stroke.
For South Asian, Chinese, Black African, or Black Caribbean adults: Lower BMI thresholds apply due to higher health risks at lower BMI levels. Eligibility may start at BMI 27.5 or above, and the healthy weight range is adjusted accordingly. Use our free BMI calculator to check your personal BMI and understand where you fall against NHS guidelines.
You cannot take Mounjaro if you are under 18, pregnant, breastfeeding, or allergic to tirzepatide. Your prescriber will assess your full medical history during consultation.
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 & What to Expect
NHS Access: NICE has approved tirzepatide (Mounjaro) for use within NHS specialist weight management services (tier 3/4). This requires a GP referral to your local specialist service. Availability and waiting times vary significantly by region. Many areas have waiting lists lasting several months or longer due to high demand.
Private Access: Mounjaro is available through UK-licensed prescribers via private online consultations. You complete a health questionnaire, are assessed by a qualified prescriber, and if suitable, receive a prescription dispensed by a GPhC-registered pharmacy. This route does not require NHS referral. Private prescription costs typically range from £129–£320 per month depending on your dose. The KwikPen device contains 4 weekly injections, so costs vary by dose escalation stage.
Whether you choose NHS or private access, your prescriber will assess whether Mounjaro is clinically appropriate for you and monitor your progress with regular check-ins.
- 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 be eligible for Mounjaro on the NHS?
You need a BMI of 30 or above, or 27–29.9 with a weight-related health condition. South Asian, Chinese, Black African, and Black Caribbean adults have lower thresholds (BMI 27.5+). Your GP can assess your eligibility and refer you to a specialist service if appropriate.
How much does Mounjaro cost privately in the UK?
Private Mounjaro costs typically range from £129–£320 per month depending on your dose. Costs increase as you titrate up from 2.5 mg to higher doses (up to 15 mg maximum). Each KwikPen contains 4 weekly injections. Exact pricing varies between private prescribers and pharmacies.
Can I get Mounjaro from my GP directly?
Your GP can discuss weight management with you and may refer you to an NHS specialist weight management service (tier 3), where Mounjaro may be prescribed. However, your GP alone typically cannot prescribe Mounjaro — it requires specialist assessment. Private online prescribers can also assess and prescribe if you choose the private route.
What happens during a private Mounjaro consultation?
You complete a detailed health questionnaire covering your medical history, current medications, weight, height, and any contraindications. A UK-licensed prescriber reviews this and may ask follow-up questions. If you're clinically suitable, they issue a prescription, which is dispensed by a GPhC-registered pharmacy and delivered to you.
How long are NHS waiting lists for Mounjaro?
NHS waiting times vary significantly by region (ICB). Some areas have waits of several months to over a year due to high demand. Your local NHS specialist weight management service can give you an estimated wait time. Private access offers faster availability but involves out-of-pocket costs.
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.