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
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Monjaro Jab: NHS Access and UK Prescribing Guide
Monjaro (tirzepatide) is a prescription-only weekly weight loss injection now available through NHS specialist services and private prescribers in the UK. This guide explains NHS eligibility criteria, how to access Monjaro through the NHS, the difference between NHS and private routes, and what to expect from this GLP-1 receptor agonist medication. Understanding your options helps you make informed decisions about weight management with your GP or healthcare team.
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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.
Monjaro on the NHS: Eligibility and Access Routes
NHS eligibility for Monjaro (tirzepatide):
- BMI of 30 kg/m² or above, OR
- BMI of 27–29.9 kg/m² with at least one weight-related health condition (type 2 diabetes, high blood pressure, high cholesterol, or sleep apnoea)
- For South Asian, Chinese, Black African, or Black Caribbean adults, lower BMI thresholds apply (from 27.5 kg/m²)
Monjaro is available through NHS tier 3 specialist weight management services — not from your standard GP practice. You'll need a referral from your GP to access specialist services in your area. NICE has approved tirzepatide for use within these specialist services. However, NHS availability varies significantly by region and integrated care board (ICB), and waiting lists can be substantial in many areas. Clinical trials (SURMOUNT-1) showed Monjaro helped participants lose an average of 15–21% of their body weight over 72 weeks, alongside reduced-calorie diet and increased physical activity — though individual results vary considerably.
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: Understanding Your Options
NHS route: Free through tier 3 specialist services, but typically involves GP referral, specialist assessment, and potentially significant waiting times. Availability depends on your region and current NHS waiting lists.
Private route: Available through GPhC-registered online prescribers without NHS referral. Faster access, but costs range from approximately £150–£300 per month depending on dose and provider. Use the BMI calculator on this page to check your starting point, and consider discussing both routes with your GP to understand what's available locally. Track your progress with our free progress tracker alongside any weight management plan.
- 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.
Can I get Monjaro on the NHS?
Yes. NICE has approved tirzepatide (Monjaro) for use in NHS tier 3 specialist weight management services. You'll need a referral from your GP. Eligibility requires a BMI of 30 or above, or 27–29.9 with weight-related health conditions. NHS availability and waiting times vary significantly by region.
What's the difference between NHS and private Monjaro prescribing?
NHS provides free access through specialist services but may have waiting lists. Private prescribers offer faster access without referral but charge approximately £150–£300 monthly. Both require clinical assessment. Private access doesn't exclude NHS options — discuss both with your GP.
How long is the NHS waiting list for Monjaro?
Waiting times vary considerably by region and integrated care board. Some areas have waiting lists of several months; others longer. Contact your local NHS weight management service or ask your GP for current waiting times in your area.
What NHS tier 3 services are, and how do I access them?
Tier 3 services are specialist multidisciplinary weight management teams (doctors, nurses, dietitians, psychologists). You access them via GP referral. They provide comprehensive assessment, lifestyle support, and prescription medication where appropriate — including tirzepatide (Monjaro).
Does Monjaro cost anything on the NHS?
No. Once prescribed through an NHS tier 3 service, Monjaro is free at point of use (standard NHS prescription charges may apply). Private prescriptions cost significantly more and are not covered by NHS.
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.