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 Weight Loss in the UK β NHS and Private Access
Mounjaro (tirzepatide) is a prescription-only weekly weight loss injection licensed in the UK for adults with obesity or overweight with health complications. NICE has approved tirzepatide for use within NHS specialist weight management services, though access varies significantly by region. This guide explains NHS eligibility criteria, how NICE and the MHRA oversee Mounjaro, and the difference between accessing it through the NHS and privately. As a dual GIP and GLP-1 receptor agonist, Mounjaro works differently to other weight loss injections like Wegovy (semaglutide), offering potentially stronger appetite suppression through its dual mechanism.
10,000+ calculations today Β· NHS-aligned thresholds Β· 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/mΒ²).
While BMI isn't a perfect measure β it doesn't account for muscle mass, bone density, or fat distribution β 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 β 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 Mounjaro Eligibility and NICE Guidance
NICE has approved tirzepatide (Mounjaro) for weight management within NHS specialist tier 3 and tier 4 weight management services. You may be eligible if you have a BMI of 30 kg/mΒ² or above, or a BMI of 27β29.9 with at least one weight-related health condition such as type 2 diabetes, prediabetes, hypertension, or sleep apnoea.
For adults of South Asian, Chinese, Black African, or Black Caribbean heritage, the NHS recommends lower thresholds β eligibility may start at BMI 27.5 or above due to higher metabolic risk in these groups.
- Mounjaro is subject to additional MHRA monitoring (Black Triangle βΌ status)
- Weight loss injections are not first-line treatments β lifestyle changes remain essential
- In NHS clinical trials, Mounjaro helped patients lose an average of 15β21% of body weight over 72 weeks, though results vary significantly
- Access through the NHS requires referral to a tier 3 specialist weight management service, typically from your GP
Clinically BackedWeight Loss
No appointments. No waiting rooms. Just care β 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 β 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 β completely free.
NHS vs Private Mounjaro Access in the UK
NHS access is limited to specialist tier 3 and tier 4 weight management services, meaning your GP cannot prescribe Mounjaro directly. You must be referred to a specialist service, which can involve waiting lists of months to years depending on your region and local ICB commissioning. Private access is available through GPhC-registered online pharmacies following an online clinical assessment with a UK-licensed prescriber β no NHS referral needed. Private costs typically range from Β£129βΒ£320 per month depending on your dose level. Whichever route you choose, Mounjaro is used alongside a reduced-calorie diet and increased physical activity for best results. 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 β 5mg β 7.5mg β 10mg β 12.5mg β 15mg
- GLP-1 receptor agonist
- Up to 15β17% body weight loss (STEP trials)
- Weekly injection, 5-step dose escalation
- NHS & private prescription available
- Doses: 0.25mg β 0.5mg β 1mg β 1.7mg β 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 | 15β22.5% | 12β17% |
| Key trial | SURMOUNT-1 (2022) | STEP 1 (2021) |
| Max dose | 15 mg weekly | 2.4 mg weekly |
| Escalation period | 20β32 weeks | 16β20 weeks |
| Administration | Weekly injection (pen) | Weekly injection (pen) |
| NHS availability | Private prescription only | NHS & private |
| Approx. private cost | Β£150βΒ£250/month | Β£150βΒ£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 β 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 is Mounjaro and how does it work for weight loss?
Mounjaro (tirzepatide) is a once-weekly prescription injection that activates two hormone pathways β GIP and GLP-1 β helping regulate appetite, reduce food cravings, and support feeling fuller after smaller meals. Its dual mechanism may offer stronger appetite suppression than single GLP-1 medications like Wegovy.
Am I eligible for Mounjaro on the NHS?
You may qualify if your BMI is 30 or above, or 27β29.9 with weight-related health conditions (diabetes, hypertension, sleep apnoea). Adults of South Asian, Black African, or Black Caribbean heritage may be eligible at BMI 27.5+. Referral to an NHS tier 3 specialist service is required.
How much weight can I lose on Mounjaro?
NHS data and clinical trials show average weight loss of 15β21% of body weight over 72 weeks, though individual results vary. Weight loss depends on dose level, diet, physical activity, and personal metabolism. Use our GLP-1 weight loss calculator to estimate potential outcomes at different doses.
Can I get Mounjaro quickly on the NHS, or should I go private?
NHS access can involve lengthy waiting lists (months to years depending on your region). Private online prescribing offers faster access if you meet eligibility criteria, though it costs Β£129βΒ£320/month. Your GP can advise which route suits your circumstances.
What is the difference between Mounjaro and Wegovy for weight loss?
Mounjaro is a dual GIP+GLP-1 agonist; Wegovy is a GLP-1 agonist only. Mounjaro averages 15βclinically studied weight loss versus Wegovy's ~15%. Both are prescription-only and require clinical assessment. Neither is assured β individual results vary significantly based on dose and lifestyle.
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.