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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Who Can Take Mounjaro in the UK?
Mounjaro (tirzepatide) is a prescription-only weight management injection available in the UK, but not everyone can take it. Eligibility depends on your BMI, age, health conditions, and whether you're accessing it through the NHS or private prescription. Understanding these criteria is the first step toward exploring whether this medication might be appropriate for you. This guide covers UK eligibility rules, access routes, costs, and what to expect from the application process.
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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
You may be eligible for Mounjaro if you are an adult aged 18 or over and meet one of these BMI thresholds:
- BMI of 30 kg/m² or above (obesity), OR
- BMI of 27–29.9 kg/m² with at least one weight-related health condition
Weight-related conditions that may qualify include type 2 diabetes or prediabetes, high blood pressure, abnormal blood fats (dyslipidaemia), obstructive sleep apnoea, or a history of heart attack or stroke.
For adults of South Asian, Chinese, Black African, or Black Caribbean heritage, the NHS recommends lower thresholds. Eligibility may start at BMI 27.5 or above because these groups face higher health risks from excess weight at lower BMI levels.
You cannot take Mounjaro if you are under 18, pregnant, breastfeeding, or allergic to tirzepatide. A prescriber will assess your full medical history before prescribing. Use our free BMI calculator above to check where you stand.
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: How to Get Mounjaro in the UK
NHS access: Mounjaro is available through NHS specialist tier 3/4 weight management services following NICE approval. You'll need a GP referral to a specialist service, which can involve lengthy waiting lists—sometimes months or years depending on your region (ICB). Once assessed by the specialist team, Mounjaro may be prescribed if clinically appropriate.
Private access: You can obtain a private prescription through a GPhC-registered online pharmacy following an online clinical consultation with a UK-licensed prescriber. This route is faster—typically days rather than months—and doesn't require an NHS referral. Private costs vary by dose and provider, ranging from approximately £129–£320 per month. A prescriber will assess your eligibility during the online consultation before dispensing.
The online consultation process for private prescriptions involves answering detailed health questions about your weight, medical history, medications, and lifestyle. The prescriber reviews your information to decide if Mounjaro is safe and suitable for you. If approved, your prescription is sent to a pharmacy for dispensing. This entire process is confidential, conducted by qualified UK-licensed prescribers, and follows the same clinical standards as NHS assessment—the main differences are speed and how you access it.
- 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 take Mounjaro in the UK?
Adults with a BMI of 30 or above can access Mounjaro. If your BMI is 27–29.9, you'll need at least one weight-related health condition (such as type 2 diabetes or high blood pressure). For South Asian, Chinese, Black African, or Black Caribbean adults, lower thresholds apply—eligibility may start at BMI 27.5. Use our free BMI calculator to find your current BMI and see where you stand.
How much does Mounjaro cost on private prescription in the UK?
Private Mounjaro costs typically range from £129–£320 per month, depending on your dose and the pharmacy provider. Starting doses (2.5 mg) are usually cheaper than maintenance doses (15 mg). Costs may vary between providers, so it's worth comparing options. NHS access is free but involves waiting for referral and assessment through specialist services.
Can I get Mounjaro through the NHS?
Yes, Mounjaro is available through NHS specialist weight management services following NICE approval. Access is via GP referral to a tier 3/4 specialist service in your area. Availability and waiting times vary significantly by region (ICB). Some areas have long waiting lists. Your GP can advise whether specialist services are available in your area and what the likely waiting time might be.
What happens during a private Mounjaro consultation?
You'll complete a detailed online health questionnaire covering your weight, medical history, current medications, allergies, and lifestyle. A UK-licensed prescriber reviews your answers to assess whether Mounjaro is safe and appropriate for you. If approved, a prescription is issued to a GPhC-registered pharmacy for dispensing. The entire process is confidential and typically takes a few days.
How does Mounjaro compare to Wegovy for UK eligibility?
Both Mounjaro (tirzepatide) and Wegovy (semaglutide) have the same UK eligibility criteria—BMI 30 or above, or BMI 27–29.9 with weight-related health conditions. Mounjaro is a dual GIP and GLP-1 receptor agonist, while Wegovy is a GLP-1 agonist only. Clinical trials showed Mounjaro may produce slightly higher average weight loss (around 20.9% at the maximum dose versus Wegovy's 14.9%), though individual results vary. Both are prescription-only and available through NHS and private routes.
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.