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 GLP-1 in the UK: NHS Access and NICE Guidance
Mounjaro is a prescription-only GLP-1 receptor agonist designed for weight management in UK adults. Unlike generic GLP-1 medications, Mounjaro also acts as a GIP receptor agonist—a dual mechanism that may support appetite regulation and weight loss. Access through the NHS is available but limited to specialist tier 3 weight management services. Understanding NHS eligibility criteria, MHRA status, and the prescribing pathway can help you navigate your options. Use our free GLP-1 weight loss calculator to explore potential outcomes, and the BMI calculator to check your starting point.
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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 Tier 3 Weight Management Services
Mounjaro (tirzepatide) is approved by the MHRA for weight management and can be prescribed through NHS specialist tier 3 and tier 4 weight management services. NHS eligibility requires 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, hypertension, or cardiovascular disease.
For adults of South Asian, Chinese, Black African, or Black Caribbean heritage, eligibility may start at a BMI of 27.5 or above due to higher metabolic risk at lower BMI levels.
Access pathway: Referral from your GP to a tier 3 specialist service is required. Availability varies significantly by region and NHS Integrated Care Board (ICB). Some areas have substantial waiting lists—often months to years. NICE has approved tirzepatide for NHS use within specialist weight management services, though implementation depends on local commissioning and resource availability.
Once assessed and prescribed, the medication is typically provided by the NHS specialist service rather than standard community pharmacy dispensing.
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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.
Mounjaro Eligibility: NHS vs Private Routes
NHS route: Requires GP referral, specialist assessment, and tier 3 service approval. NHS access is free at point of use but subject to regional availability and waiting lists. Weight loss injections through the NHS are considered a specialist intervention, not a routine primary care prescription.
Private route: Available through GPhC-registered online pharmacies following a clinical assessment by a UK-licensed prescriber. Private access doesn't require NHS referral or local service availability. Costs vary but typically range from £150–£300 per month depending on dose.
Track your progress with our free progress tracker whether you pursue NHS or private options. Whichever route you choose, Mounjaro works best alongside a reduced-calorie diet and increased physical activity.
- 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.
What is the difference between Mounjaro and other GLP-1 medications like Wegovy?
Mounjaro is a dual GIP and GLP-1 receptor agonist, while Wegovy contains only a GLP-1 agonist. Clinical trials suggest Mounjaro may produce slightly greater average weight loss, though individual results vary significantly. Both are prescription-only and available through NHS specialist services or private prescribing in the UK.
How long is the NHS waiting list for Mounjaro?
NHS waiting times vary greatly depending on your region and local ICB. Some specialist weight management services have waits of 6–12 months or longer. Contact your local tier 3 service for specific timescales. Private prescribing through accredited online pharmacies may offer faster access if you prefer to self-fund.
Can my GP prescribe Mounjaro directly through the NHS?
No. Mounjaro is prescribed only through NHS specialist tier 3 weight management services following a formal referral from your GP. Your GP can refer you, but the prescription is issued by the specialist service after assessment. This ensures appropriate patient selection and monitoring.
What does MHRA approval mean for Mounjaro?
MHRA (Medicines and Healthcare products Regulatory Agency) approval means Mounjaro has been evaluated for safety, quality, and efficacy in the UK. It's licensed for weight management in adults. Mounjaro carries a Black Triangle (▼) symbol, indicating additional monitoring for safety data. This is routine for newer medications.
Is Mounjaro available privately in the UK, and how much does it cost?
Yes, Mounjaro is available privately through GPhC-registered online pharmacies following a clinical assessment. Costs typically range from £150–£300 per month depending on dose (2.5 mg to 15 mg). Private prescribing offers faster access than NHS services but requires self-funding. Always use accredited providers.
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.