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
Who Qualifies for Mounjaro on the NHS?
Mounjaro (tirzepatide) is available through NHS specialist weight management services, but not everyone is eligible. In the UK, you may qualify if you have a BMI of 30 kg/m² or above, or BMI of 27–29.9 with weight-related health conditions. Eligibility is assessed by tier 3 specialist services following referral from your GP. This guide explains the NHS criteria, how the assessment process works, and what to expect when accessing Mounjaro through the NHS.
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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.
Understanding NHS Mounjaro Eligibility
NHS eligibility for Mounjaro is based on BMI and health status. You may qualify if you meet one of these criteria:
- BMI of 30 kg/m² or above (obesity classification), OR
- BMI of 27–29.9 kg/m² (overweight) with at least one weight-related health condition
For adults of South Asian, Chinese, Black African, or Black Caribbean descent, lower BMI thresholds apply due to higher cardiovascular and metabolic risk at lower weights — eligibility may start at BMI 27.5 or above. Weight-related conditions include type 2 diabetes, prediabetes, hypertension, abnormal blood fats, obstructive sleep apnoea, and cardiovascular disease history. Age also matters: you must be 18 or over. The NHS assesses eligibility through tier 3 specialist weight management services, not standard GP consultation. A Mounjaro KwikPen prescription requires specialist assessment, not routine primary care.
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.
NHS Access Routes and Next Steps
To access Mounjaro through the NHS, your GP must refer you to a tier 3 specialist weight management service in your local area. NHS availability varies significantly by region and integrated care board (ICB). Waiting lists for specialist services can be lengthy in many areas — sometimes several months or longer. Once referred, the specialist team will review your medical history, weight history, and current health status. They will confirm you meet NHS criteria before prescribing. If approved, you'll receive a Mounjaro prescription with guidance on injection technique, storage, and dose titration. NICE has approved tirzepatide for use within NHS weight management services. If you're not eligible through the NHS, private options for Mounjaro are available following online clinical assessment with a UK-licensed prescriber.
- 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 BMI do you need for Mounjaro on the NHS?
The standard NHS threshold is BMI 30 or above, or BMI 27–29.9 with a weight-related health condition like type 2 diabetes, high blood pressure, or cardiovascular disease. For South Asian, Chinese, Black African, or Black Caribbean adults, lower thresholds apply — starting at BMI 27.5 or above. Your GP or specialist will assess your individual circumstances.
How do I get a Mounjaro UK prescription through the NHS?
You'll need a GP referral to your local tier 3 specialist weight management service. Your GP cannot prescribe Mounjaro directly — it must come from specialist services. The specialist team will assess whether you meet eligibility criteria before issuing a Mounjaro KwikPen prescription. Waiting times vary by region and can be considerable in some areas.
What's the difference between NHS and private Mounjaro access in the UK?
NHS Mounjaro is accessed through GP referral to tier 3 services and is free at point of use but has eligibility criteria and waiting lists. Private access involves an online clinical assessment with a UK-licensed prescriber and dispensing through a GPhC-registered pharmacy — available without NHS referral but at a cost, typically £129–£320 per month depending on dose.
Are there alternative medications if I don't qualify for Mounjaro?
If you don't meet Mounjaro criteria, your specialist may suggest other approaches including lifestyle programmes, lower-cost GLP-1 options like Saxenda (liraglutide), or Wegovy (semaglutide) if eligible. Bariatric surgery may be considered for severe obesity with significant health complications. Your specialist will discuss all suitable options based on your health profile.
How long is the wait for Mounjaro on the NHS?
Waiting times for NHS specialist weight management services vary considerably by region — some areas may have waits of several months or longer. You can ask your GP approximately how long the wait is in your area when they make the referral. Check your local integrated care board (ICB) website for service information. Our free GLP-1 weight loss calculator can help you understand potential outcomes while you wait.
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.