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
Mounjaro for Type 2 Diabetes in the UK
Type 2 diabetes and excess weight often go hand in hand, and managing both can be challenging. Mounjaro (tirzepatide) is a prescription-only injection licensed in the UK that may help with both blood sugar control and weight management in adults with type 2 diabetes. This guide explains how Mounjaro works, who may be eligible through the NHS, and what the evidence shows about its effectiveness. Always consult your GP for personalised advice about whether this medication is right for you.
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.
How Mounjaro Works and NHS Eligibility
Mounjaro is a dual GIP and GLP-1 receptor agonist — different from standard GLP-1 medications like Wegovy because it activates two hormone pathways. This dual action may help regulate appetite, reduce food cravings, and improve blood sugar control in people with type 2 diabetes. The medication is administered as a once-weekly injection using a pre-filled KwikPen device.
For NHS access in the UK, NICE has approved tirzepatide (Mounjaro's active ingredient) for use in specialist weight management services. Eligibility typically includes adults with:
- Type 2 diabetes or prediabetes
- BMI of 30 or above, or 27–29.9 with weight-related health conditions
- Commitment to lifestyle changes alongside medication
NHS prescribing is through tier 3 specialist services — not standard GP prescription. Access and waiting times vary significantly by region. Your GP can refer you to your local weight management service for assessment.
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 Dose, Results, and NHS vs Private Access
Mounjaro starts at 2.5 mg per week, increasing to a maximum of 15 mg per week over approximately 20 weeks. Clinical trial data (SURMOUNT studies) showed average weight loss of approximately 20.9% body weight and improved blood sugar control at the highest dose — though individual results vary significantly.
In the UK, you can access Mounjaro via two routes: NHS specialist services (through tier 3 referral, often with waiting lists) or private prescribing through registered online services following clinical assessment. Try our free GLP-1 weight loss calculator to estimate potential outcomes, and use the BMI calculator to assess your current health status before speaking with your GP or prescriber.
- 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 for type 2 diabetes?
Yes, NICE has approved tirzepatide (Mounjaro) for use in NHS specialist weight management services. Access is through tier 3 services via GP referral, not standard primary care. Waiting times and availability vary by region (ICB). Your GP can advise on local access.
What is the difference between Mounjaro and Wegovy for diabetes?
Both contain GLP-1-related mechanisms, but Mounjaro is a dual GIP and GLP-1 agonist, whereas Wegovy is GLP-1 only. Clinical trials suggest Mounjaro may produce slightly greater average weight loss. Your prescriber will assess which is more appropriate based on your individual health profile.
How long does it take to see weight loss results with Mounjaro?
Weight loss typically begins within the first 4–8 weeks, with more significant changes evident after 12–16 weeks of treatment. Results depend on the dose reached, adherence, and lifestyle changes. Individual responses vary considerably.
Are there side effects I should know about with Mounjaro?
Common side effects include nausea, diarrhoea, constipation, and stomach pain — often temporary and reducing over time. Serious side effects are rare but may include pancreatitis or gallbladder issues. Your prescriber will monitor you and discuss any concerns.
Can Mounjaro be used for weight loss alone without diabetes?
Yes, Mounjaro is licensed for weight management in adults with a BMI of 30 or above, or 27–29.9 with weight-related conditions — with or without type 2 diabetes. However, it is prescription-only and requires clinical assessment from a licensed prescriber.
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.