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 in the UK
If you're considering Mounjaro (tirzepatide) for weight management in the UK, there are two main routes: NHS specialist services or private prescription. Mounjaro is a prescription-only, once-weekly injectable medicine that works as a dual GIP and GLP-1 receptor agonist. Access depends on your eligibility, location, and preference. This guide explains both pathways, what to expect, and how to check if Mounjaro is right for you. Always consult your GP or a qualified healthcare professional before starting any weight management treatment.
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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 Route to Mounjaro — Eligibility and Access
NHS access to Mounjaro is through tier 3 specialist weight management services. NICE (National Institute for Health and Care Excellence) has approved tirzepatide for use within the NHS, but access is not available through standard GP prescription — you must be referred to a specialist service first.
- Eligibility criteria: Adults with a BMI of 30 or above, or 25–29.9 with weight-related health conditions (type 2 diabetes, prediabetes, hypertension, dyslipidaemia, sleep apnoea, or cardiovascular disease)
- For South Asian, Chinese, Black African, or Black Caribbean adults: Lower thresholds may apply — eligibility may start at BMI 27.5 or above
- Referral process: Ask your GP for referral to your local tier 3 weight management service
- Assessment: Specialist team assesses medical history, medications, and suitability
- Waiting times: Vary significantly by region — can be several months to over a year in many areas
- Cost: Free on the NHS (if prescribed through specialist services)
Use our free BMI calculator above to check if you may meet the initial eligibility threshold, then discuss referral options with your GP.
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 Route — Online Prescription and Cost
Private access to Mounjaro is faster and does not require NHS referral. Online GPhC-registered pharmacies offer Mounjaro following a clinical assessment with a UK-licensed prescriber. The prescriber reviews your medical history and determines suitability — similar to NHS assessment but conducted remotely.
- Cost: Typically £150–£320 per month depending on dose
- Speed: Assessment and prescription within days; delivery within 1–2 weeks
- Dose progression: Starts at 2.5 mg, escalates weekly to maintenance (5–15 mg)
- No waiting list: Unlike NHS, immediate access if approved
- Ongoing support: Regular check-ins with prescriber required for safety monitoring
Try our GLP-1 weight loss calculator to estimate potential weight loss outcomes at different Mounjaro doses, then compare this with your budget and timeline.
- 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?
Yes, Mounjaro (tirzepatide) is approved by NICE for NHS use, but only through specialist tier 3 weight management services, not standard GP prescription. You must be referred by your GP and meet eligibility criteria (BMI ≥30, or ≥25–29.9 with health conditions). Waiting times vary by region but can be lengthy.
What's the difference between NHS and private Mounjaro access?
NHS access is free but requires referral, assessment, and often lengthy waiting times. Private access is faster (days to weeks), available without NHS referral, but costs £150–£320 per month. Both require clinical assessment and prescription from a UK-licensed prescriber.
How much does Mounjaro cost privately in the UK?
Private Mounjaro costs typically range from £150 to £320 per month depending on your dose (2.5 mg to 15 mg). Each KwikPen contains 4 weekly doses. Some providers offer package pricing or discounts for longer commitments. Costs vary between registered pharmacies.
What happens if I'm not eligible for NHS Mounjaro?
If you don't meet NHS criteria or face long waiting times, private prescription is available. You can access Mounjaro through an online assessment with a UK-licensed prescriber. Some people use private Mounjaro temporarily, then transition to NHS if they become eligible later.
Do I need a prescription to get Mounjaro in the UK?
Yes, Mounjaro is prescription-only in the UK. Both NHS and private routes require a valid prescription from a UK-licensed prescriber following clinical assessment. You cannot purchase it without a prescription, regardless of route.
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.