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 on the NHS — How to Access in the UK
Mounjaro (tirzepatide), the prescription weight loss injection, is available through the NHS in the UK, but access is different from getting a standard prescription from your GP. NICE has approved tirzepatide for use within specialist weight management services, and eligibility depends on your BMI and health circumstances. This guide explains NHS access pathways, MHRA approval status, eligibility criteria, and how Mounjaro compares to obtaining treatment through private routes. Understanding your options helps you take the right step for your health.
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 and Tier 3 Weight Management Services
In the UK, Mounjaro is prescribed through NHS tier 3 (specialist) weight management services, not through standard GP prescriptions. NICE (National Institute for Health and Care Excellence) has approved tirzepatide for NHS use following clinical trial data showing an average weight loss of 15–21% of body weight when used alongside diet and exercise.
You may be eligible for NHS Mounjaro if you have:
- A BMI of 30 kg/m² or above (obese category), OR
- A BMI of 27–29.9 kg/m² with a weight-related health condition such as type 2 diabetes, prediabetes, high blood pressure, abnormal blood fats, sleep apnoea, or previous cardiovascular disease
- For adults of South Asian, Chinese, Black African, or Black Caribbean heritage, lower BMI thresholds may apply (from 27.5 kg/m² or above)
Access requires a referral from your GP to your local tier 3 weight management service. This is not a medication you can request directly from your GP practice. A specialist team will assess your suitability, and if approved, they will manage your treatment, dose escalation, and monitoring throughout your Mounjaro journey.
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 Access — Timeline and Regional Variation
NHS access to Mounjaro varies significantly by region and ICB (Integrated Care Board). Waiting lists for tier 3 services can range from several months to over a year in many areas, depending on demand and local resources. If you are referred, you will typically be assessed for suitability before Mounjaro is prescribed.
Some patients choose private access through GPhC-registered online prescribing services, which bypasses NHS waiting lists. Private prescriptions require an online clinical assessment, are faster to obtain (often within days), and are managed by a private prescriber and pharmacy — but involve out-of-pocket costs ranging from approximately £129–£320 per month depending on dose.
Calculate your potential weight loss trajectory using our free GLP-1 weight loss calculator to help inform your decision about pursuing treatment.
Check your BMI and health eligibility using our free BMI calculator, which also provides context on healthy weight ranges for your height according to NHS guidelines.
- 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 in the UK?
Yes, NICE has approved tirzepatide (Mounjaro) for NHS use in specialist weight management services (tier 3). However, access is not through standard GP prescription — you must be referred to your local tier 3 service, assessed by a specialist team, and approved before treatment begins. Availability and waiting times vary significantly by region.
What is the difference between MHRA approval and NICE approval?
MHRA (Medicines and Healthcare products Regulatory Agency) approval means Mounjaro is licensed and safe for use in the UK. NICE approval means the NHS has reviewed the clinical evidence and cost-effectiveness and recommends it for specific NHS use within weight management services. Both approvals are in place for Mounjaro in the UK.
How do I get a referral to NHS Mounjaro?
Speak to your GP about weight management support. If you meet BMI and health criteria, your GP can refer you to your local tier 3 weight management service. The specialist team will then assess you for Mounjaro. You cannot self-refer to tier 3 services — GP referral is the route.
How long does it take to access Mounjaro on the NHS?
NHS waiting times vary by region and local demand. Many areas have waiting lists of 6–18+ months for tier 3 services. Private access is faster (typically within days to 2 weeks of completing an online clinical assessment), but involves cost. Check with your local ICB for current waiting times.
What is a GIP receptor agonist and how does Mounjaro differ from other weight loss injections?
Mounjaro (tirzepatide) is a dual GIP and GLP-1 receptor agonist — it activates two natural hormone pathways that regulate appetite and blood sugar. Other weight loss injections like Wegovy (semaglutide) activate GLP-1 alone. Clinical trials suggest Mounjaro may produce greater average weight loss, though individual results vary significantly.
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.