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 in the UK
Mounjaro (tirzepatide) is available in the UK through both NHS specialist weight management services and private online prescribing routes. However, availability varies significantly by region and access method. NICE has approved tirzepatide for use within NHS tier 3 and 4 specialist weight management services, but GPs cannot prescribe it in routine primary care. This guide explains your options for accessing Mounjaro, eligibility criteria, and what to expect from each route. Use our free BMI calculator to check if you might meet eligibility thresholds before seeking a prescription.
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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 — Eligibility and Tier 3 Services
NHS Mounjaro prescribing follows the tiered weight management pathway. You cannot access Mounjaro directly from your GP in most cases — you must be referred to a specialist tier 3 or tier 4 weight management service. Eligibility typically requires:
- BMI of 30 kg/m² or above, OR BMI of 27–29.9 kg/m² with weight-related comorbidities (type 2 diabetes, hypertension, cardiovascular disease, obstructive sleep apnoea, dyslipidaemia)
- For South Asian, Chinese, Black African, or Black Caribbean adults: lower thresholds may apply (BMI 27.5+)
- Evidence of previous weight loss attempts and lifestyle changes
- No absolute contraindications to GLP-1 or dual GIP/GLP-1 agonists
Once referred to tier 3, you'll undergo a comprehensive assessment including blood tests, medical history review, and discussion of benefits and side effects. NICE guidance supports dose titration from 2.5 mg up to 15 mg based on individual response and tolerability. However, NHS waiting lists for specialist services vary dramatically by region — some areas have waits of 12–24 months or longer.
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.
Private Access and Regional Variation
Private access to Mounjaro is available through GPhC-registered online pharmacies following an online clinical assessment with a UK-licensed prescriber. This route does not require NHS referral and typically offers faster access — usually within days rather than months. Private costs range from approximately £129 to £320 per month depending on dose and provider.
Regional NHS availability remains uneven. Your Integrated Care Board (ICB) determines local provision. Some areas have excellent tier 3 services with reasonable waiting times; others have very limited capacity or long waits. Contact your GP to understand your local NHS pathway, or check your ICB's commissioning strategy online. Many patients use MyWeightCheck's free GLP-1 weight loss calculator to estimate potential outcomes before committing to either 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 my GP prescribe Mounjaro directly?
No. Mounjaro is not routinely prescribed in primary care in the UK. Your GP can refer you to a specialist tier 3 weight management service, where a consultant will assess your suitability. Some private online prescribers can issue prescriptions without NHS referral, but you'll pay privately.
What's the average wait time for NHS Mounjaro?
Waiting times vary by region and local NHS capacity. Some areas have waits of 6–12 months; others exceed 24 months. Contact your local Integrated Care Board or ask your GP for an estimate. Private routes typically have much shorter waits (days to weeks).
How does Mounjaro availability compare to Wegovy on the NHS?
Both tirzepatide (Mounjaro) and semaglutide (Wegovy) are NICE-approved for NHS use, but availability depends on your local tier 3 service. Some areas prioritise one over the other based on local commissioning. Your prescriber will determine which is most appropriate for your situation.
Is Mounjaro available privately without NHS referral?
Yes. Private online prescribing services can assess your eligibility and issue a prescription following an online consultation. You'll need to pay privately (typically £129–£320/month depending on dose). No NHS referral is required.
What eligibility criteria must I meet for NHS Mounjaro?
You'll typically need a BMI of 30+ (or 27+ with weight-related health conditions like diabetes or hypertension). Assessment includes blood tests and lifestyle history review. For South Asian, Chinese, Black African, or Black Caribbean adults, lower thresholds apply. Your GP or specialist will confirm your eligibility.
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.