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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Can You Get Mounjaro From Your GP in the UK?
Getting Mounjaro (tirzepatide) from your GP depends on whether you access it through the NHS or privately. In most cases, your GP cannot prescribe Mounjaro directly, but they can refer you to specialist services where it may be available. Alternatively, Mounjaro is accessible through private online prescribing following a clinical assessment. This guide explains both pathways, NICE approval status, and how to find out what's available in your area.
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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 vs Private Prescribing — What's the Difference?
NHS access: NICE has approved tirzepatide (Mounjaro) for use within specialist tier 3 and tier 4 weight management services in the UK. However, your GP typically cannot prescribe it directly from primary care. Instead, your GP must refer you to your local specialist weight management service, usually through your Integrated Care Board (ICB). Once referred, a multidisciplinary team assesses your eligibility and decides whether Mounjaro is appropriate. NHS provision varies significantly by region — some areas have good availability, whilst others have long waiting lists of many months or years.
Private access: You can obtain Mounjaro privately through a UK-licensed prescriber following an online consultation and clinical assessment. This route does not require an NHS referral. A prescription is issued if you meet eligibility criteria, and Mounjaro is then dispensed by a GPhC-registered pharmacy. Private access is typically faster than NHS but involves a cost (usually £150–£320+ per month depending on dose).
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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 vs Wegovy — Which Might Your GP Refer You For?
Both Mounjaro (tirzepatide) and Wegovy (semaglutide) are licensed for weight management in the UK, and both require prescription and clinical assessment. The key difference is mechanism: Mounjaro is a dual GIP and GLP-1 receptor agonist, whilst Wegovy is a GLP-1 agonist only. Clinical trials (SURMOUNT for Mounjaro, STEP for Wegovy) showed Mounjaro produced average weight loss of approximately 15–21% body weight, whilst Wegovy showed around 15% on average — though individual results vary significantly. Your prescriber will assess which medication (if either) suits your individual health profile, medical history, and needs. Both require ongoing monitoring and are used alongside 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.
Will my GP prescribe Mounjaro directly?
In most cases, no. Your GP can refer you to a specialist weight management service where Mounjaro may be prescribed, but GPs do not typically issue prescriptions for Mounjaro directly from primary care. The exception is if you are already under the care of a specialist service that issues repeat prescriptions through your GP practice.
How long is the NHS waiting list for Mounjaro?
Waiting times vary dramatically by region. Some ICBs have waits of several months to over a year. Contact your local NHS weight management service for current waiting times, or ask your GP to refer you so you can join the queue in your area.
Can I get Mounjaro through private prescribing instead of waiting for the NHS?
Yes. You can access Mounjaro privately through a UK-licensed online prescriber without an NHS referral. A clinical assessment is still required. This is typically faster than NHS routes but involves private cost. Prices vary by dose and provider (usually £150–£320+ per month).
What's the difference between Mounjaro and Wegovy for weight loss?
Both are licensed for weight management in the UK and require prescription. Mounjaro is a dual GIP+GLP-1 agonist; Wegovy is GLP-1 only. Clinical trials showed Mounjaro produced slightly higher average weight loss (15–21% vs 15%), but individual results vary. Your prescriber will decide which is most suitable for you.
Do I need to meet eligibility criteria before my GP refers me for Mounjaro?
Yes. General criteria include BMI of 30+ (or 27+ with weight-related health conditions like type 2 diabetes, high blood pressure, or cardiovascular disease). For South Asian, Chinese, Black African, or Black Caribbean adults, lower thresholds may apply. Your GP can advise whether you're likely to qualify.
Ready to take control of your weight loss journey?
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