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
Can You Get Mounjaro Free on the NHS?
Mounjaro (tirzepatide) was approved by NICE in 2024 for use within NHS weight management services, making it available free to eligible patients in England, Scotland, Wales, and Northern Ireland. However, NHS access is limited to specialist tier 3 and tier 4 weight management services — not standard GP prescription. Eligibility varies by region and waiting lists can be lengthy. Understanding how NICE approval works and what the access pathway involves is essential if you're considering this treatment 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.
NHS Access Pathways and NICE Approval
NICE (National Institute for Health and Care Excellence) approved tirzepatide (Mounjaro) for adults with obesity or overweight with weight-related health conditions in November 2024. This approval means the drug can be prescribed through NHS specialist services, removing the cost barrier for eligible patients. However, approval does not mean automatic availability everywhere or to everyone.
- NHS access is through tier 3 specialist weight management services, not your GP. You must be referred by your GP to your local Integrated Care Board (ICB) weight management service
- Tier 3 services assess suitability based on BMI, comorbidities, previous weight loss attempts, and readiness for lifestyle change
- Waiting lists for NHS tier 3 services vary significantly by region — some areas have waits of 12–24 months
- NICE approval does not assures immediate NHS availability in all regions due to budget constraints and capacity
- Once prescribed, Mounjaro is dispensed free of charge through NHS prescription
Use our free BMI calculator to check your starting point and understand if you may meet the BMI threshold for NHS assessment.
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 Eligibility Criteria for Mounjaro
You may be eligible for NHS 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 BMI thresholds may apply (27.5+).
However, specialist services also assess your readiness — you'll typically need to demonstrate previous attempts at weight loss through diet and exercise, and commitment to continuing lifestyle changes alongside medication. NHS services do not prescribe Mounjaro as a standalone treatment; it's always used alongside dietary changes and activity increases.
- 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 is the NHS waiting list for Mounjaro?
Waiting times vary widely by region (ICB area). Some areas have waits of 6–12 months, others 18–24 months or longer. You can contact your local weight management service or ask your GP for typical waiting times in your area. Private prescribing offers faster access but requires payment.
Do I need a GP referral to access NHS Mounjaro?
Yes. You must ask your GP to refer you to your local tier 3 specialist weight management service. Your GP will assess whether referral is appropriate based on your BMI and health. Not all GPs refer routinely — some areas have stricter criteria. It's worth having this conversation with your GP to understand local pathways.
What's the difference between NHS Mounjaro and private Mounjaro?
NHS Mounjaro is free after NICE approval and specialist assessment. Private Mounjaro requires an online clinical assessment with a UK-licensed prescriber and costs approximately £130–£320 per month depending on dose. Private routes are faster (typically available within 1–2 weeks) but require upfront payment.
Can my GP prescribe Mounjaro directly?
Not typically. Mounjaro on the NHS must be initiated and managed by specialist tier 3 weight management services following NICE guidance, not by standard GP practice. Your GP can refer you to the service, but prescribing and monitoring happen through the specialist team. Some private GPs may offer it privately, but this requires private payment.
What happens after I'm prescribed Mounjaro on the NHS?
You'll receive dose escalation guidance (starting at 2.5 mg, increasing every 4 weeks up to 15 mg as tolerated). The specialist service monitors you regularly — typically 4-weekly appointments initially — to assess weight loss, side effects, and readiness to increase dose. You'll also receive dietary and lifestyle support. Your progress tracker can help you log weekly weight changes between appointments.
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.