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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Who Owns Mounjaro and How to Access It in the UK
Mounjaro (tirzepatide) is manufactured by Eli Lilly and Company, a major pharmaceutical manufacturer based in the United States. In the UK, Mounjaro is available as a prescription-only weight management injection for eligible adults. Access is available through both NHS specialist weight management services and private online prescribing routes. Understanding who produces it, how it works, and your options for accessing it can help you make informed decisions about your weight management journey.
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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 Mounjaro Is Made and Distributed in the UK
Eli Lilly and Company manufactures Mounjaro globally and supplies it to the UK through regulated pharmaceutical distribution channels. The medication is supplied in pre-filled KwikPen devices, each containing four weekly doses of tirzepatide. Mounjaro received UK regulatory approval from the MHRA (Medicines and Healthcare products Regulatory Agency) and is subject to additional monitoring (Black Triangle ▼ status), meaning all suspected adverse reactions are reported to ensure ongoing safety. In the UK, the tirzepatide dose range is 2.5 mg to 15 mg, administered once weekly. The KwikPen devices are refrigerated until use and must be disposed of 30 days after first opening. As a dual GIP and GLP-1 receptor agonist, Mounjaro works differently to other weight loss injections like Wegovy (semaglutide), which is manufactured by Novo Nordisk. Your prescriber will explain how Mounjaro works and whether it's appropriate for your individual health profile.
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.
Accessing Mounjaro: NHS vs Private Routes in the UK
NHS access: Mounjaro is available through NICE-approved specialist tier 3 weight management services. You'll need a GP referral and will be assessed by a multidisciplinary team. Waiting times vary significantly by region (ICB). Private access: Available through GPhC-registered online pharmacies following an online clinical assessment with a UK-licensed prescriber. No NHS referral needed. Private costs range from approximately £129–£320 monthly depending on dose. An online consultation typically takes 10–20 minutes and assesses your medical history, current medications, and eligibility. If approved, a prescription is issued and dispensed by a pharmacy. Both routes require a valid prescription and clinical assessment — Mounjaro is never available over-the-counter.
- 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.
Who manufactures Mounjaro?
Mounjaro (tirzepatide) is manufactured by Eli Lilly and Company, a major global pharmaceutical manufacturer. It's produced and supplied to the UK through regulated distribution, approved by the MHRA, and dispensed as pre-filled KwikPen devices containing four weekly doses.
Is Mounjaro available on the NHS in the UK?
Yes, Mounjaro is available through NHS specialist weight management services (tier 3). You'll need a GP referral and assessment by a multidisciplinary team. Availability and waiting times vary significantly by region. Private access is also available through online prescribing without NHS referral.
How much does Mounjaro cost privately in the UK?
Private Mounjaro costs typically range from £129–£320 per month depending on your dose. Starting doses (2.5 mg) are generally less expensive than maintenance doses (10–15 mg). Prices vary between providers. Always check current pricing and whether your dose is included in the quoted cost.
What's the difference between Mounjaro and Wegovy?
Mounjaro (tirzepatide, Eli Lilly) is a dual GIP + GLP-1 agonist. Wegovy (semaglutide, Novo Nordisk) is a GLP-1-only agonist. Both are once-weekly injections licensed for UK weight management. Mounjaro has a higher maximum dose (15 mg vs 2.4 mg). Clinical trial results show both support weight loss; individual results vary.
How do I get Mounjaro prescribed in the UK?
NHS route: ask your GP for referral to specialist weight management services. Private route: complete an online consultation with a UK-licensed prescriber through a GPhC-registered pharmacy. Both require clinical assessment. Your prescriber will check your medical history, current medications, eligibility, and BMI before approving a prescription.
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.