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 Access Mounjaro Through the NHS in the UK
Mounjaro (tirzepatide) is now approved for NHS prescribing in the UK following NICE guidance, but access is not straightforward. Unlike some GP prescriptions, Mounjaro is only available through specialist tier 3 weight management services, not standard primary care. This guide explains NHS eligibility criteria, how to get referred, and why regional availability varies significantly across England, Wales, Scotland, and Northern Ireland. If you're interested in exploring your options, our free BMI calculator can help you understand where your current weight stands against NHS thresholds.
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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 Eligibility and NICE Approval for Mounjaro
NICE approval: The National Institute for Health and Care Excellence approved tirzepatide (Mounjaro) for NHS use in 2024, but only within specialist tier 3 weight management services. This is not the same as standard GP prescribing.
Who qualifies for NHS Mounjaro:
- 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, prediabetes, high blood pressure, sleep apnoea, cardiovascular disease, or abnormal blood fats)
- Ethnicity-adjusted thresholds apply: South Asian, Chinese, Black African, and Black Caribbean adults may qualify at lower BMI (27.5 and above)
Access requires referral from your GP to a specialist tier 3 service. Mounjaro is not available on prescription from your GP directly. Regional NHS services assess your eligibility based on clinical need, available funding, and local service capacity.
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: Free at point of use once prescribed through a tier 3 service, but involves GP referral, specialist assessment, and waiting lists (often months to years in many areas). Availability depends entirely on your regional Integrated Care Board funding decisions.
Private access: Available now through GPhC-registered online prescribing services following a clinical assessment. No NHS referral needed, but you pay directly (typically £129–£320 monthly depending on dose). Both routes require a prescription from a licensed UK prescriber and evidence of clinical eligibility. Use our free GLP-1 weight loss calculator to understand projected outcomes at different doses, regardless of your chosen route.
- 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 from my GP?
Not directly from your GP. Mounjaro is only available through specialist tier 3 NHS weight management services following referral. Your GP cannot prescribe it in standard primary care. You'll need your GP to refer you to your local tier 3 service for assessment.
What is tier 3 weight management service?
Tier 3 is specialist NHS weight management, delivered by multidisciplinary teams (doctors, dietitians, psychologists). It's the third level of the NHS pathway: tier 1 is self-help, tier 2 is primary care programmes, tier 3 is specialist intervention, and tier 4 is bariatric surgery.
How long are NHS waiting lists for Mounjaro?
Waiting times vary significantly by region. Some areas have waits of 6–12 months or longer. Contact your local integrated care board or ask your GP about current waiting times in your area. Private access is available immediately if waiting times are not feasible for you.
Is Mounjaro free on the NHS?
Yes, Mounjaro is free on the NHS once prescribed through a tier 3 service. However, regional variation in availability means some areas may not currently offer it, or may have restrictive eligibility criteria beyond NICE guidance.
What's the difference between Mounjaro and Wegovy on the NHS?
Both tirzepatide (Mounjaro) and semaglutide (Wegovy) are NICE-approved for NHS weight management in tier 3 services. Mounjaro is a dual GIP/GLP-1 agonist; Wegovy is GLP-1 only. Which one you're offered depends on your local service's formulary and 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.