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 Can Have Mounjaro in the UK?
Mounjaro (tirzepatide) is a prescription-only weight management injection available in the UK through both NHS specialist services and private prescribing. Eligibility depends on your BMI, any weight-related health conditions, and other individual health factors. Understanding the criteria helps you work with your GP or a licensed prescriber to see if this medication might be suitable for you.
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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.
NHS Eligibility Criteria for Mounjaro
In the UK, Mounjaro may be prescribed through NHS tier 3 specialist weight management services if you meet one of these criteria:
- BMI of 30 kg/m² or above (obesity), OR
- BMI of 27–29.9 kg/m² (overweight) with at least one weight-related health condition
Weight-related conditions that may qualify include type 2 diabetes, prediabetes, high blood pressure, abnormal blood fats, obstructive sleep apnoea, or a history of cardiovascular disease. For adults of South Asian, Chinese, Black African, or Black Caribbean heritage, the NHS applies lower BMI thresholds — eligibility may start at BMI 27.5 or above, as these groups face higher health risks at lower BMI levels.
Access is through your GP, who refers you to a specialist tier 3 or tier 4 weight management service. NICE has approved tirzepatide (Mounjaro) for use within NHS services, though availability varies significantly by region and ICB (Integrated Care Board). Waiting times can be substantial in many areas.
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 vs Private Access in the UK
NHS access: Requires referral from your GP to a specialist weight management service. This is free but involves assessment through the NHS pathway and depends on regional availability. Many areas have waiting lists of several months.
Private access: Available through GPhC-registered online pharmacies following a clinical consultation with a UK-licensed prescriber. No NHS referral needed, but involves a cost (typically £129–£320+ per month depending on dose). Private prescribers assess your eligibility directly, and if appropriate, issue a prescription for a Mounjaro KwikPen delivered to you.
Track your weight progress with our free progress tracker while considering your treatment options.
- 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 get Mounjaro on the NHS?
Yes, if you meet NICE criteria and are referred to an NHS tier 3 specialist weight management service by your GP. Access depends on regional availability and ICB funding. Waiting times vary significantly across the UK — some areas have waiting lists of months or longer. Your GP can advise on local availability.
What BMI do I need to be eligible for Mounjaro?
NHS eligibility typically starts at BMI 30 or above, or BMI 27–29.9 if you have a weight-related health condition. For South Asian, Chinese, Black African, or Black Caribbean adults, lower thresholds apply (from BMI 27.5). Use our free BMI calculator to check your personal BMI and see where you fall.
What counts as a weight-related health condition?
Type 2 diabetes, prediabetes, high blood pressure, high cholesterol, obstructive sleep apnoea, and history of heart attack or stroke all qualify. Your GP or prescriber will assess whether your specific conditions make you eligible.
Can I get Mounjaro privately in the UK without NHS referral?
Yes. Private UK-licensed prescribers can assess and prescribe Mounjaro following an online clinical consultation. This bypasses NHS waiting lists but involves a private cost. The prescriber will still assess your medical history and eligibility.
How does Mounjaro compare to Wegovy for UK eligibility?
Both are prescription-only and use similar NHS and private eligibility criteria. Mounjaro is a dual GIP/GLP-1 agonist (maximum dose 15 mg weekly), while Wegovy is a single GLP-1 agonist (maximum dose 2.4 mg weekly). Clinical trials showed different average weight loss outcomes, though individual results vary significantly.
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.