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
Free tracker included with every download this week
How Do I Buy Mounjaro in the UK?
Mounjaro (tirzepatide) is a prescription-only weight management injection available in the UK through two main routes: NHS specialist services or private prescription following an online clinical assessment. This guide explains how to access it, what it costs, eligibility requirements, and what to expect from the prescription process. Whether you're exploring NHS options or considering private access, understanding your route is the first step toward potentially accessing this medication.
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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.
Private Prescription Route — Cost & Access in the UK
The private prescription route is currently the fastest way to access Mounjaro in the UK. You can obtain a prescription through GPhC-registered online pharmacies and prescribing services without an NHS referral. Here's what to expect:
- Online consultation: Complete a brief health questionnaire assessed by a UK-licensed prescriber (usually takes 24–48 hours)
- Prescription issued: If approved, a prescription is issued to a registered pharmacy
- Dispensing: The pharmacy dispenses your Mounjaro KwikPen and ships it to your home
- Cost: Private prescriptions typically range from £129–£320 per month depending on your dose. Starting doses (2.5 mg) are cheaper; maximum doses (15 mg) cost more
- Ongoing prescriptions: Most services offer repeat prescriptions without needing reassessment each month, though regular monitoring is advised
The cost is significantly higher than NHS prescriptions but you avoid waiting lists and can start medication within days rather than months.
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 Route vs Private — Key Differences & Process
The NHS route is free at point of use but involves a longer process. You'll need a GP referral to a specialist tier 3 or tier 4 weight management service in your area. Waiting lists vary dramatically by region — some areas have waits of 6–18 months. When you reach the service, a multidisciplinary team assesses your eligibility, which includes BMI checks using our free BMI calculator equivalent and evaluation of weight-related health conditions.
With private prescription services, the entire process — from online assessment to receiving your medication — typically takes 3–7 days. Both routes require you to be aged 18 or over, with a BMI of 30 or above (or 27 or above with qualifying health conditions). Always inform your prescriber of all current medications, as Mounjaro may affect absorption of oral medications like contraceptives.
- 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 in the UK?
Yes, Mounjaro is approved by NICE for NHS use through specialist weight management services (tier 3/4). Access requires a GP referral and varies by region. Waiting lists can be very long in many areas — typically several months to over a year. Your GP can advise on NHS availability in your region.
What does Mounjaro cost on private prescription in the UK?
Private prescriptions cost approximately £129–£320 per month depending on your dose. Starting doses (2.5 mg–5 mg) are cheaper; higher doses (10 mg–15 mg) cost more. Costs vary between different private prescribing services, so it's worth comparing options.
How long does it take to get a private Mounjaro prescription in the UK?
The private route is much faster than NHS. You typically complete an online consultation, receive approval within 24–48 hours, and your medication is dispatched within 3–7 days. Some services offer same-week delivery, making it the quickest option to start treatment.
What eligibility checks do I need for Mounjaro in the UK?
You need a BMI of 30 or above, or 27 or above with at least one weight-related health condition (diabetes, high blood pressure, sleep apnoea, heart disease). A prescriber will assess your full health history, current medications, and medical conditions during the consultation process.
Do I need a GP referral to get Mounjaro privately?
No, you don't need a GP referral for private prescription. You can access it directly through online prescribing services by completing a health questionnaire. However, it's still a good idea to inform your GP that you're taking Mounjaro so they can monitor your health appropriately.
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.