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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How to Apply For Mounjaro in the UK
Applying for Mounjaro (tirzepatide) in the UK depends on whether you access it through the NHS or privately. Both routes require a clinical assessment and prescription from a licensed healthcare professional. This guide explains your options, eligibility criteria, and the practical steps to take next. We'll also help you understand how Mounjaro works and whether it might be suitable for your situation.
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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 Route vs Private Route
NHS access to Mounjaro requires referral to a specialist weight management service (tier 3 or 4). Start by discussing weight management with your GP, who can assess whether you meet NHS eligibility criteria and refer you to a specialist service in your area. However, NHS availability varies significantly by region — waiting times can be several months to over a year in many areas.
Private access is typically faster. You can arrange a consultation with a UK-licensed prescriber through a GPhC-registered online pharmacy or private clinic. Following an online clinical assessment, if appropriate, a prescription for Mounjaro is issued and dispensed. Private treatment usually costs between £129–£320 per month depending on your starting dose.
Both routes require the same eligibility assessment and both prescriptions are subject to the same safety checks.
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.
Am I Eligible For Mounjaro?
In the UK, you may be eligible for Mounjaro if you have a BMI of 30 kg/m² or above, or a BMI of 27–29.9 with at least one weight-related health condition. Weight-related conditions include type 2 diabetes, prediabetes, high blood pressure, abnormal blood fats, sleep apnoea, or history of cardiovascular disease.
If you are of South Asian, Chinese, Black African, or Black Caribbean heritage, eligibility thresholds may start at a lower BMI (from 27.5) because these groups face higher health risks at lower weights.
Use our free BMI calculator above to check your personal BMI instantly, and discuss the results with your GP or prescriber to confirm eligibility.
You cannot take Mounjaro if you are under 18, pregnant, breastfeeding, or have a personal or family history of thyroid cancer or multiple endocrine neoplasia type 2 (MEN2). A prescriber will ask about your full medical history, current medications, and any allergies during assessment.
Note that Mounjaro is a GIP and GLP-1 receptor agonist — the dual mechanism that makes it different from single-action GLP-1 injections like Wegovy (semaglutide). Clinical trials showed tirzepatide helped participants lose an average of 15–21% of their body weight, though individual results vary significantly.
Our GLP-1 weight loss calculator can help you estimate potential weight loss at different Mounjaro doses.
- 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 happens during the clinical assessment for Mounjaro?
A licensed prescriber will review your weight history, current health conditions, medications, allergies, and lifestyle. They will discuss how Mounjaro works, expected side effects, and whether it's appropriate for you. You'll also typically have your blood pressure checked and may have blood tests ordered. The assessment is usually done online for private access or in person for NHS specialist services.
How quickly can I start Mounjaro once approved?
Private prescriptions are usually issued within 24–48 hours of approval and can be dispensed by a GPhC-registered pharmacy within a few days. NHS access depends on your regional specialist service and current waiting times — this can range from weeks to several months. Once you start, the first dose is 2.5 mg, with dose increases every 4 weeks.
Do I need my GP's permission to access Mounjaro privately?
No — you do not need GP referral or permission for private access. You can arrange a consultation directly with a UK-licensed prescriber through a private clinic or online pharmacy. However, it's good practice to inform your GP that you're taking Mounjaro so they have a complete medical record and can monitor your health.
What's the difference between Mounjaro and Wegovy for weight loss?
Mounjaro (tirzepatide) is a dual GIP+GLP-1 agonist, while Wegovy (semaglutide) is a single GLP-1 agonist. Clinical trials showed Mounjaro achieved average weight loss of 15–21%, compared to approximately 15% with Wegovy. Starting doses and maximum doses also differ. A prescriber can discuss which is more suitable for your situation.
Will the NHS eventually cover Mounjaro more widely?
NICE has approved tirzepatide (Mounjaro) for use in NHS specialist weight management services, but access remains limited by funding and availability. Regional variations are significant. Your GP can discuss NHS options in your area, but private access remains the fastest route if you want to start treatment soon.
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.