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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Weight Loss Jab Mounjaro on the NHS
Mounjaro (tirzepatide) is a prescription weight loss injection that may be available through NHS specialist services in the UK. Unlike medications you might buy privately, NHS access involves referral to a tier 3 weight management service, where clinicians assess your eligibility based on your BMI and health conditions. Availability varies significantly across different regions, and waiting lists can be lengthy. This guide explains how NHS Mounjaro works, who qualifies, and how access differs from private options using an online prescription route.
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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 NHS Mounjaro Access Works
NICE (National Institute for Health and Care Excellence) has approved tirzepatide (Mounjaro) for use within NHS weight management services. Access is through specialist tier 3 or tier 4 multidisciplinary weight management teams, not standard GP prescription. Your GP can refer you to your local specialist weight management service if they believe you may be eligible.
- Referral initiated by your GP to your local Integrated Care Board (ICB) specialist weight management service
- Assessment by a multidisciplinary team including doctors, dietitians, and behaviour change specialists
- Clinical review of your BMI, weight-related health conditions, previous weight loss attempts, and suitability
- If approved, Mounjaro is prescribed and dispensed through the NHS at no additional cost to you
- Ongoing monitoring and dose adjustments managed by the specialist team
The process typically involves several appointments and can take weeks or months depending on your local service capacity and waiting lists.
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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 Eligibility for Mounjaro
You may be eligible for NHS Mounjaro if you have:
- A BMI of 30 kg/m² or above (obesity), OR a BMI of 27–29.9 kg/m² with at least one weight-related health condition
- For South Asian, Chinese, Black African, or Black Caribbean adults: BMI 27.5 or above, due to higher health risks at lower weights
- Previous attempts at weight loss through diet and exercise
- Weight-related health conditions (type 2 diabetes, hypertension, cardiovascular disease, sleep apnoea, dyslipidaemia)
Availability and exact thresholds vary by region. You can check your local ICB's weight management service criteria online or ask your GP about what's available in your area. Our free BMI calculator can help you determine your current BMI status as a starting point.
NHS Mounjaro availability is highly variable across the UK. Some regions have excellent access with shorter waiting times, while others have significant gaps or limited capacity. Factors affecting access include: local ICB funding, service staffing, and regional demand. Waiting times can range from a few months to over a year in some areas. If NHS access is not immediately available or waiting lists are very long, some people choose to access Mounjaro privately through a licensed prescriber following an online clinical assessment — this bypasses NHS referral and waiting lists entirely. Private costs vary but typically range from £150–£320 per month depending on your dose. Try our free GLP-1 weight loss calculator to explore potential outcomes with tirzepatide at different doses, which may help inform your conversations with healthcare providers.
- 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.
How long does it take to get Mounjaro through the NHS?
NHS timelines vary significantly by region. After GP referral, you typically have an initial assessment appointment within 8–12 weeks, followed by further appointments if approved. Overall, from referral to receiving your first injection can take 3–12 months depending on your local weight management service capacity and waiting list. Contact your local ICB to understand typical waiting times in your area.
Can my GP prescribe Mounjaro directly without referral?
No. Mounjaro is not prescribed in general practice. Your GP can refer you to a tier 3 specialist weight management service, but the actual prescription and ongoing management happen within that specialist service. Private prescribing via online consultation is available outside NHS services if you wish to avoid waiting lists.
Is Mounjaro free on the NHS?
Yes. If you are prescribed Mounjaro through the NHS, there is no cost — it is dispensed as an NHS prescription at no charge to you. Private Mounjaro prescriptions are not free and typically cost £150–£320 per month depending on your dose and the provider.
What's the difference between Mounjaro and Wegovy on the NHS?
Mounjaro (tirzepatide) and Wegovy (semaglutide) are both GLP-1-type weight loss injections licensed in the UK. Mounjaro is a dual GIP and GLP-1 agonist (activating two pathways), while Wegovy is a GLP-1 agonist only. NICE has approved both for NHS use. Availability, dosing, and individual suitability vary — your specialist team will advise which is appropriate for you.
What if I can't access Mounjaro through the NHS?
If your local service doesn't offer Mounjaro, has a very long wait, or you don't meet current eligibility criteria, private prescription through a licensed UK prescriber is an alternative. This requires an online clinical assessment and costs vary by provider and dose. Always check that any prescriber is registered with the General Pharmaceutical Council (GPhC).
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.