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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What Is Mounjaro — Cost & Access in the UK
Mounjaro is a prescription-only weight management injection that's increasingly discussed in the UK. It contains tirzepatide, a dual GLP-1 and GIP receptor agonist, which means it works differently from other weight loss medications. If you're considering Mounjaro, you'll want to understand how to access it in the UK, what it costs, and whether the NHS or private route is right for you. This guide explains your options clearly and helps you make an informed decision.
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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.
How Much Does Mounjaro Cost in the UK?
Mounjaro costs vary significantly depending on whether you access it through the NHS or privately. Private prescription costs typically range from £129 to £320 per month, depending on your dose and the provider you choose. The starting dose (2.5 mg) is usually cheaper, while the maximum maintenance dose (15 mg) costs more. Each KwikPen contains 4 weeks of injections, so monthly costs are calculated per pen.
NHS costs are significantly lower if you're prescribed through specialist weight management services — you would pay standard prescription charges (currently £9.90 per item in England), or nothing if you're exempt. However, NHS access is limited and depends on your local integrated care board (ICB) commissioning the service and your eligibility meeting strict criteria. Waiting lists for NHS specialist services can be several months to over a year in many regions.
- Private route: typically £129–£320/month depending on dose
- NHS route: standard prescription charge or free if exempt
- Each dose requires a separate KwikPen (4-week supply)
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 — How to Access Mounjaro in the UK
NHS access requires a referral from your GP to a tier 3 specialist weight management service. Your GP will assess whether referral is appropriate based on your BMI, health conditions, and local commissioning. The specialist service will then conduct a full assessment and, if suitable, prescribe Mounjaro. This route is free or low-cost but involves longer waiting times and regional availability gaps.
Private access is faster: you complete an online health assessment with a UK-licensed prescriber, who reviews your medical history and determines suitability. If approved, you receive a prescription and it's dispensed by a GPhC-registered pharmacy. This takes days rather than months but costs £129–£320 monthly depending on dose.
Both routes require proper clinical assessment — Mounjaro is not available over-the-counter. Use our free GLP-1 weight loss calculator to explore potential outcomes at different doses, and our free BMI calculator to assess your starting point.
NHS access requires a referral from your GP to a tier 3 specialist weight management service. Your GP will assess whether referral is appropriate based on your BMI, health conditions, and local commissioning. The specialist service will then conduct a full assessment and, if suitable, prescribe Mounjaro. This route is free or low-cost but involves longer waiting times and regional availability gaps.
Private access is faster: you complete an online health assessment with a UK-licensed prescriber, who reviews your medical history and determines suitability. If approved, you receive a prescription and it's dispensed by a GPhC-registered pharmacy. This takes days rather than months but costs £129–£320 monthly depending on dose.
Both routes require proper clinical assessment — Mounjaro is not available over-the-counter. Use our free GLP-1 weight loss calculator to explore potential outcomes at different doses, and our free BMI calculator to assess your starting point.
- 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.
Is Mounjaro available on the NHS in the UK?
Yes, Mounjaro (tirzepatide) has been approved by NICE for NHS use in specialist weight management services. However, availability depends on your local ICB's commissioning decisions and waiting lists are often very long. You'll need a GP referral to a tier 3 specialist service. Private access is available without NHS referral but costs £129–£320 monthly depending on your dose.
What is the typical cost of Mounjaro privately in the UK?
Private Mounjaro costs range from approximately £129 to £320 per month, depending on your starting dose and maintenance dose. The starting dose (2.5 mg) is usually cheaper; the maximum dose (15 mg) is more expensive. Each KwikPen contains 4 weeks of injections. Costs vary slightly between different GPhC-registered providers.
How long does it take to access Mounjaro privately?
Private access is typically faster than NHS. You can usually complete an online health assessment within hours or days, receive a decision from the prescriber within 1–2 days, and have your first pen dispatched within 2–5 days. NHS specialist services typically involve waiting lists of several months to over a year, depending on your region.
What's the difference between Mounjaro and Wegovy in terms of access and cost?
Both are prescription-only weight loss injections available privately at similar costs (£129–£320/month). Mounjaro is a dual GIP+GLP-1 agonist; Wegovy is a GLP-1 agonist only. Both are available through NHS specialist services (where approved), though with significant waiting lists. Private prescribers assess both and can advise which may be more suitable for you.
Do I need a clinical assessment to get Mounjaro?
Yes, absolutely. Mounjaro is prescription-only and requires a clinical assessment regardless of whether you access it through the NHS or privately. The prescriber will review your medical history, current medications, weight, BMI, and health conditions to ensure Mounjaro is safe and appropriate for you. Self-diagnosis or online ordering without assessment is not available in the UK.
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.