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
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Mounjaro Qualifications in the UK — Who Can Access It?
Mounjaro (tirzepatide) is available in the UK through both NHS specialist services and private prescription routes, but eligibility varies depending on your weight, health conditions, and which pathway you choose. This guide explains who qualifies, how the UK prescription system works, and what to expect in terms of costs and access timelines.
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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.
UK Eligibility Criteria for Mounjaro Prescription
To qualify for Mounjaro on the NHS, you typically need a BMI of 30 kg/m² or above, or a BMI of 27–29.9 kg/m² if you have at least one weight-related health condition such as type 2 diabetes, prediabetes, high blood pressure, abnormal blood fats, obstructive sleep apnoea, or cardiovascular disease history. Lower BMI thresholds may apply if you're of South Asian, Chinese, Black African, or Black Caribbean heritage — eligibility may start at BMI 27.5 or above, reflecting higher health risks at these weights for these populations.
Check your BMI instantly using our free BMI calculator above to see where you stand. You cannot take Mounjaro if you're under 18, pregnant or breastfeeding, or allergic to tirzepatide. For private prescription access, eligibility criteria are similar, though some private prescribers may assess on an individual basis. Your prescriber will review your full health history, current medications, and weight-related conditions during an online clinical 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.
NHS vs Private Access — Costs, Timelines & How to Get Started
NHS access: Free through specialist tier 3/4 weight management services, but access varies significantly by region and waiting lists can extend several months or years in many areas. You'll need a GP referral. Private access: Available through GPhC-registered online pharmacies without NHS referral. Costs typically range from £129–£320 per month depending on your dose — starting doses like 2.5 mg cost less than maintenance doses of 10–15 mg. Private prescriptions are processed faster (often within days) and don't require waiting lists. Both routes require a clinical assessment from a UK-licensed prescriber before your prescription is issued. Individual results vary, and all weight loss medication works best alongside a reduced-calorie diet and increased physical activity.
- 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 BMI do I need to qualify for Mounjaro in the UK?
You generally need a BMI of 30 or above, or 27–29.9 if you have a weight-related health condition like type 2 diabetes, high blood pressure, or sleep apnoea. If you're of South Asian, Chinese, Black African, or Black Caribbean heritage, lower thresholds apply — eligibility may start at BMI 27.5. Use our BMI calculator to check your personal BMI instantly.
How long does it take to get Mounjaro on the NHS?
NHS access is through specialist weight management services (tier 3/4), requiring a GP referral. Waiting times vary by region but can range from several months to over a year in many areas. Private routes are typically faster, often within days of your clinical assessment being approved.
How much does Mounjaro cost privately in the UK?
Private Mounjaro typically costs £129–£320 per month depending on your dose. Starting dose (2.5 mg) is usually cheaper; maintenance doses (10–15 mg) cost more. Prices vary between providers, so comparing quotes is worthwhile. This is in addition to the prescriber consultation fee.
Can I get Mounjaro without a prescription in the UK?
No. Mounjaro is prescription-only in the UK and requires a clinical assessment from a UK-licensed prescriber — either through NHS specialist services or a private online prescriber. This ensures it's safe for you based on your health history and current medications.
What happens after I'm prescribed Mounjaro — how do I start?
After your prescription is approved, your pharmacy dispenses your first KwikPen. You'll start on 2.5 mg weekly, then increase gradually every 4 weeks if tolerated — moving through 5 mg, 7.5 mg, 10 mg, 12.5 mg, to a maximum of 15 mg. You'll inject once weekly into your stomach, thigh, or upper arm. Track your progress with our free progress tracker.
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.