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 Manufactures Mounjaro and How Is It Supplied?
Mounjaro (tirzepatide) is manufactured by Eli Lilly and Company, a major global pharmaceutical corporation. The medication is supplied in the UK as a pre-filled KwikPen injection device for once-weekly administration. Mounjaro is approved by the MHRA for weight management in UK adults and is subject to additional monitoring (Black Triangle ▼ status). Understanding the manufacturer and supply chain can help you feel confident about the medication's quality and safety standards.
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.
About Eli Lilly and Mounjaro Production
Eli Lilly and Company is a Fortune 500 pharmaceutical manufacturer founded in 1876, headquartered in Indianapolis, USA. The company has a strong track record in metabolic and endocrine medicines. Mounjaro (tirzepatide) is manufactured to strict pharmaceutical standards and undergoes rigorous quality control before distribution.
Mounjaro uses a dual GIP and GLP-1 receptor agonist mechanism — a unique approach that distinguishes it from other weight loss injections like Wegovy (semaglutide), which activates only the GLP-1 pathway. This dual mechanism may help reduce appetite, support feeling fuller after meals, and assist with fat utilisation.
- Manufactured to MHRA and international pharmaceutical standards
- Pre-filled KwikPen format for ease of use
- Subject to additional MHRA monitoring (Black Triangle ▼)
- Each pen contains 4 weekly doses
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.
Mounjaro Supply and Prescription in the UK
In the UK, Mounjaro is available through two main routes: NHS specialist weight management services (tier 3/4) and private prescribing through registered online services. NHS access requires referral from your GP to a specialist service, though availability varies significantly by region and waiting lists can be lengthy. Privately, Mounjaro is dispensed by GPhC-registered pharmacies following an online clinical assessment with a UK-licensed prescriber.
Regardless of supply route, Mounjaro is prescription-only and requires clinical assessment to confirm eligibility. Your prescriber will assess your BMI, health conditions, and suitability before issuing a prescription. Use our GLP-1 weight loss calculator to estimate potential outcomes, and our BMI calculator to check your current status.
- 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 made by Novo Nordisk?
No. Mounjaro (tirzepatide) is manufactured by Eli Lilly and Company. Novo Nordisk manufactures Wegovy (semaglutide), a different weight loss injection. Both are GLP-1-based medications licensed in the UK, but they are made by different pharmaceutical companies and use different mechanisms.
Why is Mounjaro subject to Black Triangle (▼) monitoring?
Black Triangle status means the MHRA is conducting additional monitoring for safety. This is common for newer medicines and does not indicate a safety problem — it reflects the MHRA's commitment to gathering comprehensive safety data as the medication is used across the UK population.
How is Mounjaro quality controlled?
Mounjaro is manufactured by Eli Lilly to strict MHRA and international pharmaceutical standards. Each batch undergoes rigorous quality testing before distribution. The pre-filled KwikPen format ensures precise dosing and maintains medication stability until use.
Can I get Mounjaro on the NHS in the UK?
Mounjaro is available on the NHS through specialist tier 3/4 weight management services, typically requiring GP referral. However, availability and waiting times vary significantly by region and ICB (Integrated Care Board). Private prescribing through registered online services is also available without NHS referral.
What's the difference between Mounjaro and Wegovy?
Mounjaro (tirzepatide, Eli Lilly) is a dual GIP and GLP-1 receptor agonist. Wegovy (semaglutide, Novo Nordisk) is a GLP-1 agonist only. Both are once-weekly injections for weight management, but the dual mechanism of Mounjaro may produce different results. Clinical trials show both can support meaningful weight loss alongside lifestyle changes.
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.