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
Who Owns Mounjaro and How It's Prescribed in the UK
Mounjaro (tirzepatide) is owned and manufactured by Eli Lilly and Company, a major pharmaceutical manufacturer. In the UK, Mounjaro is licensed for weight management and approved by the MHRA (Medicines and Healthcare Products Regulatory Agency). Access is available through two main routes: specialist NHS tier 3 weight management services or private prescribing. Understanding who manufactures this medication and how UK prescribing works can help you navigate your options. Use our free BMI calculator to check your weight status and explore whether you might be eligible for prescription weight loss treatment.
10,000+ calculations today · NHS-aligned thresholds · 100% free
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 Ownership and MHRA Approval in the UK
Eli Lilly and Company manufactures Mounjaro (tirzepatide) globally, including for UK supply. Eli Lilly is a large pharmaceutical corporation headquartered in the United States, and tirzepatide represents one of their significant recent approvals in weight management. Mounjaro received MHRA approval in the UK and is subject to additional monitoring (Black Triangle ▼ status), meaning the MHRA closely monitors safety data. The medication is supplied as a pre-filled KwikPen device containing four once-weekly doses. In the UK, Mounjaro is available through two distinct pathways: NHS specialist weight management services (tier 3) following GP referral, and private online prescribing through GPhC-registered pharmacies. Both routes require a clinical assessment before dispensing. NICE has approved tirzepatide for use within NHS specialist services, though regional availability varies significantly across England, Scotland, Wales, and Northern Ireland.
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 Access vs Private Access for Mounjaro in the UK
The NHS route involves referral from your GP to a specialist tier 3 or tier 4 weight management service. These services assess your eligibility based on BMI and weight-related health conditions, then prescribe and monitor your treatment. NHS access is free at point of care but waiting lists can be lengthy in many areas—sometimes months or years depending on your region. The private route allows you to access Mounjaro through an online clinical assessment with a UK-licensed prescriber without NHS referral. Private treatment is available more quickly but involves cost (typically £200–£300+ per month depending on dose). Both routes require the same clinical suitability assessment. Our GLP-1 weight loss calculator can help you explore potential outcomes at different doses, regardless of which access route you choose.
- 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) is available through NHS specialist weight management services (tier 3). You need a GP referral and assessment by the specialist service. Regional availability varies, and waiting lists can be significant. Some NHS regions have better access than others. Check with your GP about local services.
Who manufactures Mounjaro?
Mounjaro is manufactured by Eli Lilly and Company, a major global pharmaceutical corporation. The medication is supplied as a pre-filled KwikPen device with four once-weekly doses. Eli Lilly also manufactures other medications used in diabetes and weight management.
What is the difference between NHS and private Mounjaro prescribing in the UK?
NHS prescribing is free but requires GP referral to specialist services and often involves waiting lists. Private prescribing is faster, available through online assessment, but involves cost (typically £200–£300+ monthly). Both require clinical assessment and the same eligibility criteria apply.
How does Mounjaro compare to Wegovy in the UK?
Both are prescription-only weight management injections available in the UK. Mounjaro (tirzepatide) is a dual GIP and GLP-1 agonist; Wegovy (semaglutide) is a GLP-1 agonist only. Both are licensed, available via NHS specialist services or privately, and have clinical trial evidence for weight loss. Individual suitability is assessed case-by-case.
What does MHRA approval mean for Mounjaro in the UK?
MHRA (Medicines and Healthcare Products Regulatory Agency) approval means Mounjaro meets UK safety, quality, and efficacy standards. It has Black Triangle (▼) status, meaning the MHRA actively monitors safety data. This is normal for newer medications and indicates careful oversight, not a safety concern. ```
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.