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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Mounjaro Private vs NHS — How to Access in the UK
If you're considering Mounjaro (tirzepatide) for weight management in the UK, you have two main routes: NHS specialist services or private prescription. Both offer legitimate access to this prescription-only injection, but they differ significantly in eligibility pathways, waiting times, costs, and how quickly you can start treatment. Understanding these differences helps you decide which route suits your situation best.
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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 — Key Differences
NHS access is available through NICE-approved specialist tier 3 and tier 4 weight management services. Your GP refers you to your local integrated care board's (ICB) weight management pathway. NICE has approved tirzepatide for use within these specialist services, meaning it can be prescribed at no direct cost to you. However, NHS waiting times vary dramatically by region — some areas have waiting lists of 12–24 months, while others may offer faster access. You'll need a BMI of 30 or above, or 27–29.9 with weight-related health conditions (type 2 diabetes, hypertension, sleep apnoea, or cardiovascular disease).
Private prescription bypasses NHS waiting lists entirely. You book an online consultation with a UK-licensed prescriber through a GPhC-registered pharmacy, answer health questions, and receive a prescription if clinically suitable. Private Mounjaro typically costs £180–£320 per month depending on your dose and provider — you pay per prescription. Access is immediate (within days), and there are no waiting lists. The same eligibility criteria apply, but the assessment happens privately rather than through NHS services.
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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 Medication Matters More Than Access Route
Many people researching Mounjaro also compare it to Wegovy (semaglutide), and this choice is often more important than the access route itself. Both are prescription-only injections licensed for weight management in the UK. Mounjaro is a dual GIP and GLP-1 receptor agonist — it activates two hormone pathways simultaneously, which may help it achieve slightly higher average weight loss than Wegovy in clinical trials. The SURMOUNT-1 trial showed Mounjaro users lost approximately 15–21% of body weight on average at maximum dose. Wegovy, a GLP-1 agonist only, showed approximately 15% average weight loss in STEP trials. However, individual results vary significantly — some people respond better to one medication than the other. Your prescriber will assess which is more suitable based on your health profile, previous treatments, and contraindications. Use our GLP-1 weight loss calculator to explore potential outcomes at different doses.
The medication choice is a clinical decision made between you and your prescriber — not determined by whether you access NHS or private routes. Both NHS and private prescribers can prescribe either Mounjaro or Wegovy, though NHS availability depends on regional ICB approval and stock. Private prescribers typically have faster access to both medications. Cost differences exist: NHS prescription medications are free once prescribed, while private Mounjaro runs £180–£320/month and private Wegovy typically £129–£280/month depending on dose and provider. Both require clinical assessment, and both are used alongside reduced-calorie diet and increased physical activity for best results.
- 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.
How long is the NHS waiting list for Mounjaro?
NHS waiting times vary dramatically by region. Some ICBs offer access within 3–6 months; others have waiting lists of 12–24 months or longer. Contact your local integrated care board or ask your GP for realistic timescales in your area. Private prescription access is typically available within 1–7 days.
Is Mounjaro cheaper on the NHS or private prescription?
Mounjaro is free on the NHS once prescribed through a specialist service — you pay nothing per dose. Private prescription costs £180–£320 per month depending on your dose and provider. However, NHS access involves waiting times; private offers immediate access for a cost.
Do I need a GP referral for private Mounjaro?
No. Private prescription Mounjaro does not require a GP referral. You can book a consultation directly with a private prescriber through a GPhC-registered pharmacy. However, informing your GP is recommended so your medical records are updated and your GP can monitor your progress.
What's the difference between Mounjaro and Wegovy?
Mounjaro (tirzepatide) is a dual GIP and GLP-1 receptor agonist; Wegovy (semaglutide) is a GLP-1 agonist only. Clinical trials suggest Mounjaro may achieve slightly higher average weight loss (15–21% vs 15%), though individual results vary. Both are prescription-only, and both are available on NHS and private routes in the UK.
Am I eligible for Mounjaro on either route?
Eligibility criteria are the same for both NHS and private: BMI 30 or above, or 27–29.9 with weight-related health conditions (type 2 diabetes, hypertension, cardiovascular disease, sleep apnoea). Lower BMI thresholds apply if you're of South Asian, Chinese, Black African, or Black Caribbean heritage. An NHS or private prescriber will assess your individual suitability.
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.