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
Can Doctors Prescribe Mounjaro in the UK?
Yes, doctors can prescribe Mounjaro (tirzepatide) in the UK — but access depends on where you seek treatment. Your GP may refer you to an NHS specialist weight management service, or you can access Mounjaro privately through an online clinical assessment with a UK-licensed prescriber. Mounjaro is a prescription-only medicine, so it's only available following proper clinical evaluation. Eligibility is based on BMI and health factors. Use our free GLP-1 weight loss calculator to understand how Mounjaro may support your weight management journey alongside lifestyle changes.
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 vs Private Mounjaro Prescription Routes
In the UK, you can access Mounjaro through two main routes: NHS specialist services or private prescription.
NHS Route: Your GP can refer you to a tier 3 or tier 4 specialist weight management service. These multidisciplinary teams assess whether Mounjaro is appropriate for you. However, NHS availability varies significantly by region and ICB (Integrated Care Board), and waiting lists can be lengthy — sometimes many months or years. Not all areas offer Mounjaro on the NHS yet, even though NICE has approved tirzepatide for use within specialist weight management services.
Private Route: You can access Mounjaro privately through a GPhC-registered online pharmacy following a clinical assessment with a UK-licensed prescriber. This route does not require an NHS referral and is typically faster, though there is a cost. Prescribers will assess your BMI, health history, and suitability before issuing a prescription. Both routes require a clinical assessment — Mounjaro cannot be obtained without proper medical evaluation.
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.
Who Is Eligible for Mounjaro Prescription?
Your eligibility for Mounjaro depends on your BMI and health status. Adults with a BMI of 30 kg/m² or above, or a BMI of 27–29.9 kg/m² with at least one weight-related health condition, may be eligible. Weight-related conditions include type 2 diabetes, prediabetes, high blood pressure, abnormal blood fats, sleep apnoea, or a history of cardiovascular disease.
For adults of South Asian, Chinese, Black African, or Black Caribbean heritage, lower BMI thresholds apply (typically 27.5 and above) because these groups face higher metabolic health risks at lower weights. You must be 18 or older, not pregnant or breastfeeding, and have no contraindications such as a personal or family history of medullary thyroid cancer. Check your personal eligibility using our free BMI calculator above, then discuss with your GP or a prescriber.
- 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 automatically prescribe Mounjaro?
No. Your GP will assess your individual health and may refer you to a specialist weight management service rather than prescribing Mounjaro directly. NHS GPs typically cannot initiate Mounjaro — it's usually prescribed through specialist tier 3 or tier 4 services. Private prescribers can issue Mounjaro following an online clinical assessment.
What's the difference between Mounjaro and Wegovy?
Both are prescription-only weight loss injections licensed in the UK. Mounjaro (tirzepatide) is a dual GIP and GLP-1 receptor agonist, while Wegovy (semaglutide) is a GLP-1 receptor agonist only. Clinical trials showed Mounjaro resulted in slightly higher average weight loss (~20.9% at maximum dose) compared to Wegovy (~14.9%), though individual results vary significantly.
Can I get Mounjaro prescribed without seeing a doctor?
No. Mounjaro is prescription-only and requires a clinical assessment by a UK-licensed prescriber before being prescribed. This can be done via online consultation with a private prescriber, but you must provide health information and be assessed as suitable. You cannot obtain Mounjaro without medical evaluation.
How long does it take to get Mounjaro on the NHS?
Waiting times vary significantly by region. Some specialist services have waiting lists of several months to over a year. Private prescribing is typically faster — often within 1–2 weeks of your assessment. Check with your local NHS weight management service for their current waiting times.
What happens after my doctor prescribes Mounjaro?
Your prescriber will explain how to inject Mounjaro using the KwikPen device, starting at 2.5 mg weekly. You'll be guided through dose escalation over weeks, and your progress will be monitored. You'll need to follow a reduced-calorie diet and increase physical activity. Regular check-ins with your prescriber help ensure the treatment is working and side effects are manageable.
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.