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
How to Apply for Mounjaro on the NHS
Getting Mounjaro (tirzepatide) on the NHS in the UK requires referral to a specialist tier 3 weight management service, not through your standard GP prescription. NICE has approved tirzepatide for use within NHS weight management services, but access varies significantly by region and depends on meeting specific eligibility criteria. This guide explains the NHS pathway, what makes you eligible, and what to expect from application through to prescription.
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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 Eligibility Criteria and the Tier 3 Pathway
To apply for Mounjaro on the NHS, you must first meet weight-related eligibility criteria and be referred to a tier 3 (or tier 4) specialist weight management service. Standard GP practices do not prescribe Mounjaro directly — it is only available through these specialist NHS services.
You may be eligible if you have:
- A BMI of 30 kg/m² or above, or
- A BMI of 27–29.9 kg/m² alongside a weight-related health condition such as type 2 diabetes, prediabetes, high blood pressure, abnormal blood fats, obstructive sleep apnoea, or cardiovascular disease history
- For adults of South Asian, Chinese, Black African, or Black Caribbean heritage, lower BMI thresholds may apply — eligibility may start at BMI 27.5 or above due to higher health risks at lower weights
Check your BMI instantly using our free BMI calculator above, then discuss referral with your GP if you meet these criteria.
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 vs Private Route: Understanding Your Options
The NHS pathway offers Mounjaro at no cost if approved, but involves waiting lists and regional variation — some areas have delays of months or years. The private route means consulting a UK-licensed prescriber online and obtaining a prescription through a GPhC-registered pharmacy, without NHS referral. Private costs range from approximately £129–£320 monthly depending on dose. Both routes require a clinical assessment confirming you meet eligibility criteria. Your GP referral to tier 3 is the first step on the NHS route; if you wish to explore private access, you can do so independently while waiting for NHS assessment.
- 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 do I ask my GP to refer me for Mounjaro on the NHS?
Contact your GP surgery and explain you're interested in specialist weight management services. Mention your BMI and any weight-related health conditions. Your GP can then refer you to your local tier 3 weight management service. The referral process and waiting times vary by region and NHS integrated care board.
What is NICE guidance on Mounjaro prescribing in the UK?
NICE has approved tirzepatide (Mounjaro) as a treatment option within NHS tier 3 weight management services for eligible adults. However, NICE guidance emphasises that prescription should only follow clinical assessment and be used alongside lifestyle changes — diet and physical activity support remain essential.
What's the difference between tier 3 and tier 4 weight management services?
Tier 3 services are specialist weight management clinics in secondary care (hospital-based or community services). Tier 4 services are highly specialised centres dealing with severe obesity and complex cases. Most Mounjaro prescriptions come through tier 3. Your GP referral determines which service is appropriate for your situation.
Can I get Mounjaro faster by going private instead of waiting for NHS?
Yes. Private online prescribing services can typically provide a prescription within days if you meet eligibility criteria, whereas NHS tier 3 waiting lists can extend months or years depending on your region. Private costs apply, but you avoid the wait — you can explore both routes simultaneously.
Does Mounjaro eligibility depend on trying other weight loss methods first?
Some NHS tier 3 services may require evidence of previous weight loss attempts or completion of lifestyle programmes before prescribing. This varies by service and region. Private prescribers typically assess you individually. Ask your GP or the tier 3 service directly about their specific requirements when referred.
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.