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
How to Apply for Mounjaro on the NHS
Mounjaro (tirzepatide) is available on the NHS for weight management, but access requires a referral to specialist services rather than a standard GP prescription. The process starts with your GP, who will assess your eligibility based on your BMI, health conditions, and medical history. Understanding the NHS pathway helps you know what to expect and whether Mounjaro might be suitable for you. This guide explains the full application and referral process in 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 and the Referral Pathway
To access Mounjaro through the NHS, you must be referred to a tier 3 or tier 4 specialist weight management service. Your GP cannot prescribe Mounjaro directly — they assess your eligibility and refer you onwards. NICE (National Institute for Health and Care Excellence) has approved tirzepatide for use in specialist services for adults with a BMI of 30 kg/m² or above, or 27–29.9 kg/m² with weight-related health conditions such as type 2 diabetes, high blood pressure, or cardiovascular disease.
If you are of South Asian, Chinese, Black African, or Black Caribbean heritage, lower BMI thresholds may apply — eligibility could start at BMI 27.5 or above due to higher health risks at lower BMI in these populations. Use our free BMI calculator above to check your current BMI and see whether you may meet NHS eligibility criteria.
- BMI 30+ (or 27.5+ for certain ethnicities) may qualify
- Weight-related health conditions strengthen eligibility
- Previous weight loss attempts are assessed
- Current medications are reviewed
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.
Steps to Apply: GP Referral to Specialist Assessment
Start by booking an appointment with your GP and explain that you are interested in weight management support and specialist assessment. Your GP will review your medical history, current weight, height, and any weight-related conditions. If you meet initial criteria, your GP will refer you to your local Integrated Care Board (ICB) specialist weight management service — this is typically a hospital or community clinic offering tier 3 or tier 4 care.
Once referred, you will be added to a waiting list and invited for an assessment appointment with a weight management team (doctors, nurses, dietitians). They will discuss Mounjaro, assess whether it is suitable, explain how the medication works, review potential side effects, and discuss lifestyle changes alongside treatment. Regional variation is significant — some areas have shorter waiting times than others. If approved, your first dose (2.5 mg) is typically scheduled within weeks of approval.
Track your progress with our free progress tracker if you are approved for treatment. Our GLP-1 weight loss calculator can also help you estimate potential weight loss at different Mounjaro doses based on clinical trial data, though individual results vary significantly. Keep regular GP appointments throughout treatment to monitor side effects, blood sugar levels (if diabetic), and weight progress.
- 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.
Can I ask my GP to prescribe Mounjaro directly?
No. Mounjaro is not prescribed in general practice. Your GP assesses eligibility and refers you to a specialist weight management service. Only specialist teams in tier 3 or tier 4 services can prescribe Mounjaro on the NHS. This ensures proper medical oversight and monitoring.
What if I don't meet NHS eligibility criteria?
If you don't qualify for NHS Mounjaro, private online prescribing is available. A UK-licensed prescriber assesses your suitability following an online consultation. If approved, Mounjaro can be prescribed and dispensed by a GPhC-registered pharmacy. Costs vary by dose but typically range from £129–£320 per month.
How long is the NHS waiting list for Mounjaro?
Waiting times vary significantly by region and local ICB resources. Some areas have waiting lists of several months; others may take a year or longer. Ask your GP about expected waiting times in your area when you request a referral. Private options are available if you prefer not to wait.
What happens at the specialist weight management assessment?
The team will review your medical history, current weight, BMI, and weight-related health conditions. They will discuss how Mounjaro works, explain potential side effects, assess injection technique, and discuss diet and physical activity changes. If approved, treatment planning and follow-up appointments are arranged.
Is Mounjaro assured to work on the NHS?
Mounjaro is not assured. Clinical trials showed average weight loss of 15–21% body weight, but individual results vary. The specialist team will monitor your progress and adjust doses or consider alternatives if you are not losing weight as expected. Treatment is combined with dietary and 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.