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
Mounjaro NHS Guidelines — What You Need to Know
Mounjaro (tirzepatide) is approved by NICE for use within NHS specialist weight management services, but access works differently from standard GP prescriptions. Understanding the current NHS guidelines, eligibility criteria, and how to access Mounjaro through the NHS will help you determine whether this prescription-only medication may be suitable for your circumstances. This guide explains the official UK health service pathway and what the evidence shows.
10,000+ calculations today · NHS-aligned thresholds · 100% free
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 for Mounjaro
NICE has approved tirzepatide (Mounjaro) for use in NHS weight management services for adults who meet specific criteria. You may be eligible if you have a BMI of 30 kg/m² or above, or a BMI of 27–29.9 kg/m² with at least one weight-related health condition such as type 2 diabetes, prediabetes, high blood pressure, abnormal blood fats, obstructive sleep apnoea, or a history of cardiovascular disease.
For adults of South Asian, Chinese, Black African, or Black Caribbean heritage, the NHS applies lower BMI thresholds due to higher health risks at lower weights. Check your BMI using our free BMI calculator above to see whether you fall within these ranges.
- BMI 30 or above (or 27.5+ for certain ethnic groups)
- At least one weight-related health condition present
- Failed to achieve sustainable weight loss through lifestyle changes alone
- No contraindications (pregnancy, breastfeeding, certain medical conditions)
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.
Accessing Mounjaro Through the NHS
Mounjaro is not available through standard GP prescription — instead, it is prescribed through tier 3/4 specialist weight management services. To access NHS Mounjaro, you must first be referred to your local specialist weight management service by your GP. These services are provided by Integrated Care Boards (ICBs) across the UK, but availability varies significantly by region.
Waiting times for NHS specialist services can be substantial — in many areas, waiting lists extend several months or longer. Private prescribing offers faster access through online clinical assessments with UK-licensed prescribers, though costs apply. Either route requires a clinical assessment to confirm Mounjaro is appropriate for your individual health profile and medical history.
NHS guidelines emphasise that Mounjaro is used alongside, not instead of, dietary changes and increased physical activity. The NICE guidance recommends that prescribing occurs within a structured weight management programme that includes behavioural support and lifestyle modification. Our GLP-1 weight loss calculator can help you understand potential weight loss outcomes based on clinical trial data, though individual results vary significantly.
If you think you may be eligible, speak to your GP about referral to your local specialist weight management service. They can assess your health, discuss whether Mounjaro is suitable, and explain both NHS and private options available to you in your area.
- 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 Mounjaro (tirzepatide) for use in NHS specialist weight management services. However, it is not available through standard GP prescription — you must be referred to a tier 3/4 specialist service. Availability varies significantly by region, and waiting lists can be long.
What BMI do I need for NHS Mounjaro?
You typically need a BMI of 30 or above, or 27–29.9 with weight-related health conditions like type 2 diabetes or high blood pressure. For South Asian, Chinese, Black African, or Black Caribbean adults, lower thresholds apply (BMI 27.5+). Check your BMI using our calculator above.
How do I access Mounjaro on the NHS?
Ask your GP for a referral to your local specialist weight management service. They will assess your eligibility, discuss whether Mounjaro is appropriate, and prescribe if suitable. Regional availability varies — some areas have shorter waiting times than others.
What is the difference between NHS and private Mounjaro?
NHS access is through specialist services (free but may involve waiting lists), while private access uses online prescribing services (faster but costs apply). Both routes require clinical assessment. Private costs typically range from £129–£320 per month depending on dose.
Does Mounjaro work without diet and exercise changes?
No. NHS guidelines emphasise that Mounjaro is used alongside lifestyle changes, not instead of them. The clinical trials showing weight loss all combined the medication with reduced-calorie diet and increased physical activity for best results.
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.