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 Can You Get Mounjaro On The NHS?
Getting Mounjaro (tirzepatide) on the NHS in the UK is possible but requires going through specialist weight management services. NICE has approved tirzepatide for use within the NHS, but access is typically through tier 3 or tier 4 services rather than standard GP prescription. You'll need a referral from your GP, a clinical assessment showing you meet eligibility criteria, and availability in your local area. This guide explains the NHS route, how it compares to private access, and what to expect at each stage.
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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 and The Tier 3 Pathway
To access Mounjaro through the NHS, you must first meet MHRA and NICE eligibility criteria. You need 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, high blood pressure, or cardiovascular disease). If you are of South Asian, Chinese, Black African, or Black Caribbean heritage, lower thresholds may apply — eligibility may begin at BMI 27.5 or above due to higher health risks in these populations.
The NHS operates a four-tier weight management pathway. Tier 1 involves self-help and community programmes. Tier 2 offers GP-led behaviour change support. Tier 3 is where prescription medications like Mounjaro are typically initiated — this is a specialist multidisciplinary weight management service. Your GP must refer you to tier 3, which varies significantly by region and ICB (Integrated Care Board). Once referred, you'll undergo a full clinical assessment, including blood tests and health history review, before a specialist team decides whether Mounjaro is appropriate for you. Tier 4 (bariatric surgery) is reserved for severe obesity with significant comorbidities.
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 — What's The Difference?
NHS access is free at point of use but involves waiting lists that can extend several months to over a year in many regions. You have no choice of medication within tier 3 — the service will recommend what they consider most suitable. You cannot usually access Mounjaro through your GP; it must come through the specialist service. In contrast, private access is available through GPhC-registered online prescribing services following a clinical assessment, typically within days, with choice of medication (Mounjaro vs Wegovy), but costs range from approximately £150–£320 per month depending on dose.
Both routes require a prescription from a UK-licensed prescriber and a genuine clinical assessment — neither route offers medication without proper evaluation. NHS access is appropriate if you can wait and prefer NHS care; private access is faster and gives more choice but involves out-of-pocket cost. Use our free BMI calculator to confirm your eligibility category, then speak to your GP about the best route for you.
- 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.
Do I need a GP referral to get Mounjaro on the NHS?
Yes. You must ask your GP for a referral to your local tier 3 specialist weight management service. Your GP will assess whether a referral is appropriate and forward your details. Direct self-referral to tier 3 services is not available; the NHS route requires GP involvement at the start.
How long does it take to get Mounjaro through the NHS?
Waiting times vary significantly by region. Some areas have waiting lists of 3–6 months; others can exceed 12 months. Tier 3 services are under high demand. You can ask your GP approximately how long the wait is in your area when requesting a referral.
What if my local NHS doesn't offer Mounjaro?
Some tier 3 services offer GLP-1 medications (like Wegovy or Saxenda) but not Mounjaro. This varies by region and ICB funding decisions. If Mounjaro is not available locally, the service may recommend an alternative weight loss injection, or you may consider private access.
Is Mounjaro free on the NHS once prescribed?
Yes. All prescription medications prescribed through the NHS are available at the standard prescription cost (£9.65 in England as of 2024) or free if you qualify for free prescriptions. Once a tier 3 service prescribes Mounjaro, you collect it at an NHS pharmacy.
Can I switch from NHS Mounjaro to a private prescription?
Yes. If you start on NHS Mounjaro through tier 3 services and later want to switch to private prescribing, you can do so. However, there may be a gap while you transition. Discuss any switch with both your NHS specialist and private prescriber to avoid gaps in medication.
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.