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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How To Get Mounjaro For Weight Loss in the UK
Getting Mounjaro (tirzepatide) for weight loss in the UK involves two main routes: NHS specialist services or private prescription. Both require a clinical assessment to confirm you meet eligibility criteria. Mounjaro is a prescription-only weekly weight loss injection that works as a dual GIP and GLP-1 receptor agonist. Access varies depending on your circumstances, local NHS availability, and whether you choose private or public healthcare. This guide explains both pathways and how to determine which suits you.
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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 vs Private Access: Routes to Get Mounjaro
In the UK, you can access Mounjaro through two distinct pathways, each with different timelines and costs.
NHS Route: Your GP can refer you to a specialist tier 3 or tier 4 weight management service, where a multidisciplinary team assesses your eligibility. According to NICE guidance, you qualify if you have a BMI of 30 or above, or 27–29.9 with weight-related health conditions (type 2 diabetes, hypertension, dyslipidaemia, sleep apnoea, or cardiovascular disease). NHS prescriptions are free once approved, but waiting lists vary significantly by region—some areas have waits of 12–18 months. Access depends on your Integrated Care Board (ICB) funding and capacity.
Private Route: You can obtain a prescription through a GPhC-registered online pharmacy after an online clinical assessment with a UK-licensed prescriber. This bypasses NHS waiting lists and is available within days. Costs typically range from £129–£320 per month depending on your dose. Private prescriptions require you to meet the same clinical eligibility criteria and demonstrate that a prescriber believes the medication is suitable for you. For South Asian, Chinese, Black African, and Black Caribbean adults, lower BMI thresholds (from 27.5) may apply due to higher metabolic health risks at lower weights.
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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.
Mounjaro vs Wegovy: Which Route Works for You?
Both Mounjaro (tirzepatide) and Wegovy (semaglutide) are UK-licensed weekly weight loss injections, but they differ in mechanism and clinical trial results. Mounjaro is a dual GIP and GLP-1 receptor agonist, whereas Wegovy is a GLP-1 agonist only. In the SURMOUNT clinical trial, Mounjaro achieved average weight loss of approximately 15–21% of body weight at the highest dose (15 mg), whilst STEP trial data showed Wegovy at approximately 15% at 2.4 mg. Individual results vary significantly. Your prescriber will assess which is most suitable based on your health profile, any existing medical conditions, and other medications you take. Both require the same eligibility assessment and clinical decision-making. The choice often depends on local availability, prescriber experience, and individual patient factors. Use our free GLP-1 weight loss calculator to explore potential outcomes with either medication, and our BMI calculator to confirm your starting position.
- 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 on the NHS in the UK?
Yes, but access is limited. Your GP can refer you to a specialist weight management service (tier 3 or 4), where you'll be assessed against NICE criteria. Eligibility requires a BMI of 30 or above, or 27–29.9 with weight-related health conditions. Waiting lists vary widely by region, from 6 months to over 18 months. Not all ICBs fund tirzepatide yet, so availability depends on your area.
What is the fastest way to get Mounjaro?
The fastest route is private prescription through a GPhC-registered online pharmacy. After an online clinical assessment with a UK-licensed prescriber, you can receive a prescription and medication within days if approved. This costs approximately £129–£320 per month depending on your dose and provider.
Do I need to see my GP before getting Mounjaro privately?
You do not need a GP referral for private prescription, but you will need a clinical assessment from a UK-licensed prescriber. They will review your medical history, current medications, BMI, and any weight-related health conditions to determine suitability. It's sensible to inform your GP if you start taking Mounjaro privately so they have a complete picture of your healthcare.
What's the difference between Mounjaro and Wegovy?
Mounjaro (tirzepatide) is a dual GIP and GLP-1 receptor agonist, whilst Wegovy (semaglutide) is a GLP-1 agonist only. Mounjaro's dual mechanism may provide stronger appetite suppression. In clinical trials, Mounjaro showed average weight loss of 15–21% body weight, whilst Wegovy showed approximately 15%. Both are prescription-only and require clinical assessment. Your prescriber will recommend the most suitable option for your individual circumstances.
How much does Mounjaro cost privately in the UK?
Private Mounjaro costs typically range from £129–£320 per month, depending on your dose and the provider. Starting doses (2.5 mg) cost less than higher maintenance doses (15 mg). Some providers offer tiered pricing or package deals. Always confirm the total cost upfront, including any consultation fees. NHS prescriptions are free once approved, but involve waiting lists.
Ready to take control of your weight loss journey?
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