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 — Cost, Instructions & Routes
Mounjaro (tirzepatide) is a prescription-only weight management injection that requires a clinical assessment before you can access it in the UK. You can obtain Mounjaro through two main routes: NHS specialist weight management services or private prescription via a licensed online pharmacy. This guide explains how the Mounjaro KwikPen works, what you'll pay depending on your route, and what to expect during the assessment process. Whether you're considering NHS or private access, understanding your options helps you make an informed decision about your weight management journey.
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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.
Mounjaro Cost and Access Routes in the UK
NHS Access to Mounjaro: NICE has approved tirzepatide (Mounjaro) for use within specialist tier 3 weight management services across the UK. However, NHS access is not straightforward — you'll need a GP referral to your local integrated care board's (ICB) specialist weight management service. NHS availability varies significantly by region, and waiting lists can extend from several months to over a year in some areas. Once approved, Mounjaro is free on the NHS.
Private Access and Cost: Private prescription through a GPhC-registered online pharmacy typically costs between £129 and £320 per month, depending on your dose. Starting doses (2.5 mg) are usually at the lower end, while higher maintenance doses cost more. You'll need to complete an online clinical assessment with a UK-licensed prescriber, who will determine if Mounjaro is suitable for you. Private prescriptions can be issued without NHS referral, offering faster access than the NHS route.
- NHS route: free but involves waiting lists and regional variation
- Private route: faster access, costs £129–£320/month, requires valid prescription
- Both routes require clinical assessment and eligibility checks
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.
Using the Mounjaro KwikPen — What to Expect
The Mounjaro KwikPen is a pre-filled injection device designed for ease of use at home. Each pen contains four doses (one month's supply). Your prescriber will show you how to inject before you use it at home, and written instructions are included in the pack. The pen stores in the fridge at 2–8°C when unopened, or at room temperature (below 30°C) for up to 30 days after first use. You inject once weekly into your stomach, upper thigh, or upper arm — rotating injection sites each week to avoid skin irritation. If you miss a dose within 4 days, take it as soon as you remember; if more than 4 days have passed, skip that dose and continue your normal schedule. Try our free GLP-1 weight loss calculator to see projected results at different Mounjaro doses alongside your clinical assessment.
- 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's the difference between NHS and private Mounjaro access in the UK?
NHS access is free but requires a GP referral to specialist services and involves waiting lists (often several months). Private access via licensed online pharmacies costs £129–£320 monthly depending on dose but offers faster access without referral. Both require clinical assessment and evidence of eligibility (BMI ≥30 or ≥27 with weight-related health conditions).
How much does Mounjaro cost privately in the UK?
Private Mounjaro costs typically range from £129 to £320 per month, depending on your dose level. Starting doses (2.5 mg) cost less; maximum doses (15 mg) cost more. Some providers offer package deals for longer courses. Prices may vary slightly between providers, so it's worth comparing. Prescriptions require a valid clinical assessment.
Can I get Mounjaro on the NHS, and how long does it take?
Yes, NICE has approved Mounjaro for NHS specialist weight management services. You'll need a GP referral to your local ICB's tier 3 service. Waiting times vary significantly by region — some areas have 6-month waits, others 12+ months. Check with your GP about current waiting times in your area. Once approved, it's free.
How do I use the Mounjaro KwikPen?
The Mounjaro KwikPen is pre-filled with a weekly dose. Inject it once per week into your stomach, thigh, or upper arm, rotating sites each week. Your prescriber or pharmacist will demonstrate the injection technique. Store unopened pens in the fridge (2–8°C); opened pens can be kept at room temperature for up to 30 days. Each pen contains four weeks' supply.
Do I need a clinical assessment before getting Mounjaro?
Yes, a clinical assessment is required whether you access Mounjaro through the NHS or privately. A UK-licensed prescriber will review your medical history, BMI, weight-related health conditions, current medications, and suitability for tirzepatide. This assessment ensures Mounjaro is safe for you and helps determine your starting dose and monitoring plan.
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.