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 on the NHS — What You Need to Know
Mounjaro (tirzepatide) is a prescription-only weight loss injection now available through the NHS in the UK, though access varies significantly by region. As a dual GIP and GLP-1 receptor agonist, it works differently from other weight loss medications by activating two natural hormone pathways to help regulate appetite and support weight management. This guide explains how to access Mounjaro through the NHS, eligibility criteria, waiting times, and what to expect from the prescription process. Understanding your options can help you decide whether NHS or private routes are right for you.
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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.
How to Access Mounjaro Through the NHS
NICE approval: The National Institute for Health and Care Excellence (NICE) has approved tirzepatide (Mounjaro) for use within specialist weight management services across the NHS. However, this does not mean it is available from your GP like a standard prescription.
Tier 3 specialist services: Mounjaro is only prescribed through NHS tier 3 specialist weight management services, not through primary care. You typically need a referral from your GP to these services, usually based on:
- BMI of 30 kg/m² or above (or 27–29.9 with weight-related health conditions)
- Previous attempts at weight loss through diet and lifestyle
- Readiness to commit to ongoing weight management
- No contraindications to the medication
Regional variation: Availability differs significantly across NHS regions. Some areas have specialist weight management services with access to Mounjaro, whilst others have limited access or significant waiting lists. Your local Integrated Care Board (ICB) determines availability in your area.
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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 Waiting Times and Private Alternatives
NHS waiting times for tier 3 specialist weight management services range from several months to over a year in some regions, and not all services currently offer Mounjaro. If you need timely access, you can obtain a prescription through private online assessment with a UK-licensed prescriber, followed by dispensing from a GPhC-registered pharmacy. Private costs typically range from £129–£320 monthly depending on dose. Calculate your potential weight loss with our free GLP-1 weight loss calculator to understand outcomes at different doses. Check your current BMI using our BMI calculator, then discuss both NHS and private options with your GP to find the best route for your circumstances.
- 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, NICE has approved tirzepatide (Mounjaro) for NHS use within specialist tier 3 weight management services. However, availability depends on your region, and you typically need a GP referral. Not all NHS areas offer it, and waiting lists can be lengthy. Ask your GP whether your local service provides Mounjaro.
What are the NHS eligibility criteria for Mounjaro?
Generally, a BMI of 30 kg/m² or above, or 27–29.9 with weight-related conditions like type 2 diabetes, high blood pressure, or sleep apnoea. South Asian, Chinese, Black African, or Black Caribbean adults may have lower thresholds. Your GP or specialist will assess your individual eligibility.
How long does it take to get Mounjaro on the NHS?
Waiting times vary widely by region, often ranging from 3 months to over a year. Some areas have no waiting time for specialist services, whilst others have very long lists. Contact your local NHS weight management service to ask about current waiting times in your area.
Can I get Mounjaro privately instead of waiting for the NHS?
Yes. You can access Mounjaro through private online prescription services, dispensed by GPhC-registered pharmacies. This typically costs £129–£320 monthly depending on dose. You'll have a private clinical assessment and can begin treatment much faster than the NHS route.
Is Mounjaro the same as Ozempic?
No. Mounjaro (tirzepatide) is a dual GIP and GLP-1 agonist approved for weight loss. Ozempic (semaglutide) is also a GLP-1 agonist but is licensed for type 2 diabetes management, not weight loss. Mounjaro and Wegovy (semaglutide for weight loss) are the two main NHS-approved weight loss injections.
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.