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
Is Mounjaro Free on the NHS?
Mounjaro (tirzepatide) is available on the NHS, but access is limited and varies significantly by region. It's not available through your standard GP prescription — you'll need a referral to a specialist tier 3 or tier 4 weight management service. NICE has approved tirzepatide for NHS use, but waiting lists can be lengthy, and many areas have strict eligibility criteria. Many people access Mounjaro privately through online prescribers instead. This guide explains NHS access, costs, and your options in the UK.
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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 Access to Mounjaro — How It Works
Mounjaro is officially approved by NICE for use within the NHS, but you cannot simply ask your GP for a prescription. Instead, you must follow the specialist weight management pathway:
- Tier 1: Your GP assesses you and may refer you to specialist services if you meet eligibility criteria
- Tier 2: Community weight management programmes and structured support
- Tier 3: Specialist multidisciplinary weight management services — this is where prescription weight loss medications like Mounjaro may be considered
- Tier 4: Bariatric surgery centres for severe obesity
If approved at tier 3, Mounjaro is dispensed free through the NHS. However, regional variation is significant — some ICBs (Integrated Care Boards) have lengthy waiting lists, others have restricted access, and a few areas have very limited tier 3 services. You may wait 6–18 months or longer for an NHS appointment in some regions. Our free GLP-1 weight loss calculator can help you understand potential outcomes if you do access treatment.
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 Eligibility and Private Alternatives
To be considered 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, hypertension, or sleep apnoea). Even if you meet eligibility criteria, NHS access depends on your local ICB's funding and waiting capacity.
Many people choose private online prescribing instead. Private tirzepatide costs approximately £150–£320 per month depending on dose titration and provider. You don't need an NHS referral — just a consultation with a UK-licensed prescriber. This pathway is often faster, though it's not free. Check your personal BMI using our free BMI calculator to understand your starting point, then discuss options with your GP or a private prescriber.
- 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 Mounjaro free on the NHS?
Yes, if approved through a specialist tier 3 weight management service. NICE has approved tirzepatide for NHS use. However, access is limited by region, waiting lists are often very long (6–18+ months), and eligibility criteria are strict. You cannot get it from your standard GP — you need a specialist referral and assessment.
What's the difference between NHS and private Mounjaro?
The medication is identical. NHS Mounjaro is free but involves waiting and specialist referral. Private Mounjaro requires an online clinical assessment and costs £150–£320/month but is usually faster to access. Both require a UK-licensed prescriber's prescription and clinical assessment.
What are the NHS eligibility criteria for Mounjaro?
Generally, a BMI of 30 or above, or 27–29.9 with weight-related health conditions (diabetes, hypertension, sleep apnoea, cardiovascular disease). South Asian and other ethnic minority adults may have lower BMI thresholds. Your GP assesses whether you meet local ICB criteria — eligibility varies by region.
How long is the NHS waiting list for Mounjaro?
This varies significantly by region. Some areas have waiting lists of 6–12 months; others are 18+ months or longer. A few regions have very limited tier 3 services. Contact your local ICB or ask your GP for the current waiting time in your area.
Is Mounjaro the same as Ozempic or Wegovy?
No. Mounjaro (tirzepatide) is a different medication — a dual GIP and GLP-1 agonist. Wegovy (semaglutide) is a GLP-1-only medication, also available on NHS and privately. Ozempic is also semaglutide but approved for diabetes, not weight loss. All three are prescription-only and require clinical assessment.
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.