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 Many People Are On Mounjaro in the UK?
The exact number of UK adults currently prescribed Mounjaro (tirzepatide) is not publicly released by manufacturers or the NHS, but demand for this once-weekly injection has grown significantly since its approval for weight management. This guide explains what we know about Mounjaro uptake in the UK, who is eligible, and how to access this prescription medication through NHS or private routes. If you're considering whether Mounjaro might be right for you, our free GLP-1 weight loss calculator can help you explore potential outcomes based on current clinical trial data.
10,000+ calculations today · NHS-aligned thresholds · 100% free
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.
What We Know About Mounjaro Usage in the UK
While exact prescribing numbers for Mounjaro (tirzepatide) are not publicly available, several indicators suggest rapidly increasing usage. Since NICE approved tirzepatide for weight management in 2023, NHS specialist weight management services have been prescribing it alongside Wegovy (semaglutide). Private online prescribing has also grown substantially, with many GPhC-registered pharmacies reporting high demand. The SURMOUNT clinical trials showed Mounjaro helped participants lose an average of 15–21% of body weight across different doses, which has driven significant patient interest. Unlike Ozempic (which is used for diabetes and is not licensed for weight loss), Mounjaro is specifically approved for weight management. However, NHS access remains limited by waiting lists and regional ICB availability — some areas have waits of several months to over a year for tier 3 specialist services. Private prescribing offers faster access but requires payment.
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.
Who Is Currently 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 such as type 2 diabetes, prediabetes, high blood pressure, sleep apnoea, or cardiovascular disease. For people 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 health risks at lower weights. To check your personal BMI, use our free BMI calculator above. Mounjaro is prescription-only and requires a clinical assessment to confirm suitability. Access is through NHS specialist weight management services or a private online consultation with a UK-licensed prescriber. You must be 18 or over; the medication is not suitable during pregnancy or while breastfeeding.
- 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.
Is Mounjaro available on the NHS?
Yes, Mounjaro (tirzepatide) is approved by NICE for NHS use within specialist tier 3 weight management services. However, NHS access varies significantly by region and waiting lists are often long. Many people access it privately through online prescribing instead.
How does Mounjaro differ from Wegovy?
Mounjaro is a dual GIP and GLP-1 receptor agonist, while Wegovy (semaglutide) is GLP-1 only. Mounjaro has a higher maximum dose (15 mg vs 2.4 mg) and clinical trials showed slightly higher average weight loss, but individual results vary considerably.
How much weight loss can I expect from Mounjaro?
Clinical trials showed average weight loss of 15–21% of body weight over 72 weeks, alongside a reduced-calorie diet and increased physical activity. Results vary significantly between individuals — some lose more, some less. Use our GLP-1 weight loss calculator to explore projected outcomes.
What are the most common side effects of Mounjaro?
The most common side effects are nausea, diarrhoea, vomiting, constipation, and stomach pain. These often improve as the body adjusts. Serious side effects are rare but can include pancreatitis — seek immediate medical attention if you experience severe stomach pain.
How do I access Mounjaro in the UK?
NHS access is through referral to a specialist weight management service — ask your GP. Private access is through online consultation with a UK-licensed prescriber and a GPhC-registered pharmacy. Private prescriptions are available without NHS referral but cost approximately £129–£320 per month depending on dose.
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.