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
Is Mounjaro for Diabetes?
Mounjaro (tirzepatide) is not primarily licensed for diabetes treatment in the UK — it is approved specifically for weight management in adults. However, because tirzepatide works on the same hormone pathways that regulate blood sugar, it may help improve blood glucose control as a side effect of weight loss. If you have type 2 diabetes and are overweight, your GP or prescriber can discuss whether Mounjaro might be suitable for your situation. It's important to understand the difference between Mounjaro and other semaglutide medications like Ozempic, which is licensed for diabetes but not for weight loss in the UK.
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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's Licence and Diabetes
Mounjaro is licensed in the UK for weight management, not diabetes treatment. The medication (tirzepatide) is a dual GIP and GLP-1 receptor agonist — it activates two hormone pathways in the body. While these pathways are also involved in blood sugar regulation, Mounjaro's UK approval is specifically for adults with a BMI of 30 or above, or 27–29.9 with weight-related health conditions such as type 2 diabetes, high blood pressure, or cardiovascular disease.
That said, because obesity and excess weight significantly contribute to type 2 diabetes, weight loss achieved with Mounjaro may improve blood glucose control as an indirect benefit. Clinical trials of tirzepatide showed improvements in glycaemic control, but this was a secondary observation, not the primary purpose of the medication.
If you have type 2 diabetes and are also overweight, a specialist prescriber or your GP can assess whether Mounjaro may be appropriate for your individual circumstances. You can use our free GLP-1 weight loss calculator to estimate potential weight loss outcomes, which may help inform that conversation.
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 vs Ozempic — What's the Difference?
A common source of confusion in the UK is the difference between Mounjaro and Ozempic — both are semaglutide medications, but they serve different purposes. Ozempic is approved for type 2 diabetes management and is injected as a once-weekly dose of up to 2 mg. Mounjaro (tirzepatide) is a different medication approved specifically for weight management, not diabetes.
Using Ozempic off-label for weight loss is not recommended or licensed in the UK. If you have type 2 diabetes and need weight management support, your GP or prescriber can discuss Mounjaro eligibility, which may be appropriate if you meet the BMI and health criteria. Always ensure any prescription weight loss medication is obtained through a licensed prescriber following a 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.
Can I take Mounjaro if I have type 2 diabetes?
Mounjaro is not licensed for diabetes treatment, but it may be prescribed for weight management in adults with type 2 diabetes who meet the BMI criteria (30 or above, or 27–29.9 with health conditions). Weight loss achieved through Mounjaro may help improve blood glucose control. Your GP or specialist prescriber can assess your individual eligibility and suitability.
Is Mounjaro the same as Ozempic?
No. Ozempic contains semaglutide and is licensed for type 2 diabetes. Mounjaro contains tirzepatide and is licensed for weight management. They are different medications with different approval purposes in the UK. Never use either medication off-label without prescriber guidance.
Will Mounjaro help my blood sugar if I have diabetes?
Mounjaro is not primarily designed to treat diabetes, but weight loss from Mounjaro may indirectly help improve blood glucose control, especially if excess weight is contributing to your diabetes. This would be a secondary benefit of weight loss, not the medication's primary function. Always discuss with your prescriber.
How do I get Mounjaro prescribed in the UK?
Mounjaro is prescription-only and requires a clinical assessment from a UK-licensed prescriber. You can access it through NHS specialist weight management services (tier 3) or via a private online consultation with a registered prescriber. Eligibility is based on BMI and health criteria, not diabetes status alone.
Can I use the BMI calculator to check if I might be eligible for Mounjaro?
Yes. Use our free BMI calculator to find your current BMI — this is one of the first steps in assessing Mounjaro eligibility. A BMI of 30 or above, or 27–29.9 with weight-related conditions, may qualify you. A prescriber will assess your full medical history and health before deciding. ```
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.