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
Where To Buy Mounjaro In The UK
If you're looking for Mounjaro (tirzepatide) in the UK, it's available through two main routes: NHS specialist weight management services or private online prescribing. Mounjaro is a prescription-only medicine, so you'll need a prescription from a UK-licensed prescriber following a clinical assessment. This guide explains your options, eligibility requirements, and what the process involves. You can also use our free GLP-1 weight loss calculator to estimate potential outcomes at different tirzepatide doses.
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.
NHS Access To Mounjaro
NHS access to Mounjaro is through tier 3 specialist weight management services, not standard GP prescription. NICE has approved tirzepatide for use within NHS specialist weight management programmes, but availability varies significantly by region (Integrated Care Board area).
- Referral required: Your GP must refer you to your local NHS tier 3 weight management service
- Assessment: Specialists will assess whether you meet eligibility criteria (BMI 30+, or 27–29.9 with weight-related health conditions)
- Waiting lists: In many areas, waiting times for NHS specialist services can be several months to over a year
- Regional variation: Some ICB areas have more accessible services than others; some have limited or no access to tirzepatide
Contact your GP to ask about local NHS weight management services and referral routes in your area. Use our BMI calculator above to check your current BMI and see whether you may be within eligibility thresholds.
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.
Private Prescribing And Costs
Private route: Mounjaro is available through GPhC-registered online pharmacies following an online clinical assessment with a UK-licensed prescriber. This route doesn't require NHS referral.
- How it works: Complete an online consultation, a prescriber reviews your health information, and if approved, your prescription is dispensed by a regulated pharmacy
- Cost: Typically £129–£320+ per month depending on dose (higher doses cost more)
- Speed: Generally faster than NHS access — you can start treatment within days if approved
- Flexibility: You remain in control of your treatment; you can pause or stop at any time
Private prescribing is a legitimate route used by thousands of UK adults. Always ensure any provider is GPhC-registered and uses a real UK prescriber, not just an automated assessment. Track your progress with our free progress tracker once you start treatment.
- 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.
What's the difference between Mounjaro and Wegovy for weight loss in the UK?
Both are prescription-only weight management injections. Mounjaro (tirzepatide) is a dual GIP+GLP-1 agonist; Wegovy (semaglutide) is a GLP-1 agonist only. Clinical trials showed Mounjaro achieved slightly higher average weight loss (~15–21% body weight vs ~15% with Wegovy), though individual results vary. Both require clinical assessment before prescription.
How much does Mounjaro cost privately in the UK?
Private Mounjaro costs typically range from £129–£320+ per month depending on your dose. The 2.5 mg starting dose is cheaper than higher maintenance doses (15 mg). Some providers offer monthly or annual payment plans. Always check the exact cost with your chosen provider, as prices vary.
Can my GP prescribe Mounjaro, or do I need a specialist?
NHS prescribing is through specialist tier 3 weight management services, not standard GP prescription. Your GP can refer you, but they don't typically prescribe it themselves. Privately, you can access prescribers online without GP referral. Either way, you need a prescription-only medicines prescription from a licensed prescriber.
How long is the NHS waiting list for Mounjaro?
Waiting times vary significantly by region. Some areas have waits of several months to over a year for NHS tier 3 weight management services. Contact your local service to ask about current waiting times. Private access is often faster (typically days to weeks) if you go the private route instead.
Is Mounjaro safe to use long-term in the UK?
Mounjaro is licensed for long-term weight management. It carries a Black Triangle (▼) status, meaning it requires additional MHRA monitoring, but this is a precautionary measure. Common side effects include nausea, diarrhoea, and constipation, most mild and temporary. Always discuss long-term use with your prescriber and report any unusual symptoms.
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.