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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How to Get Prescribed Mounjaro in the UK
Getting prescribed Mounjaro (tirzepatide) in the UK involves two main routes: through the NHS or via private prescription following an online clinical assessment. Mounjaro is a prescription-only, once-weekly injectable medicine that may help support weight loss alongside diet and exercise. This guide explains eligibility criteria, the prescription process, and what to expect at each stage. Use our free BMI calculator above to check if you might meet the eligibility threshold for Mounjaro treatment.
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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 Route: Specialist Weight Management Services
The NHS route to Mounjaro begins with your GP. You'll need a referral to a tier 3 specialist weight management service in your area. Eligibility typically requires a BMI of 30 or above, or 27–29.9 with weight-related health conditions such as type 2 diabetes, high blood pressure, or sleep apnoea. For adults of South Asian, Chinese, Black African, or Black Caribbean heritage, lower thresholds may apply due to increased health risks at lower BMI levels.
Once referred, you'll be assessed by a multidisciplinary team including doctors, dietitians, and psychologists. If Mounjaro is deemed suitable, a specialist will prescribe and manage your treatment. Important: NHS availability varies significantly by region. Many areas have substantial waiting lists—sometimes several months or longer. NICE has approved tirzepatide for NHS use, but access depends on your local Integrated Care Board (ICB) funding and capacity.
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.
Private Route: Online Clinical Assessment
The private route offers faster access without NHS referral. You'll complete an online consultation with a UK-licensed prescriber through a GPhC-registered pharmacy. The prescriber will assess your medical history, current medications, weight, BMI, and suitability for Mounjaro treatment. If approved, a prescription is issued and dispensed by post. Costs typically range from £129–£320 per month depending on dose and provider.
Private prescribing follows the same clinical standards as NHS prescribing—you must meet eligibility criteria and have a valid clinical reason for treatment. Dose titration (gradual increases from 2.5 mg to your maintenance dose) follows standard protocols. Try our GLP-1 weight loss calculator above to estimate potential weight loss at different Mounjaro doses, which you can discuss with your 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.
What is the main difference between getting Mounjaro on the NHS vs privately?
NHS access is through specialist tier 3 services with referral from your GP—it's free but often involves waiting lists. Private access is faster, requires an online clinical assessment, and costs money but doesn't require NHS referral or waiting. Both routes require clinical eligibility assessment.
What BMI do I need to be prescribed Mounjaro?
You typically need a BMI of 30 or above, or 27–29.9 with weight-related health conditions like type 2 diabetes, high blood pressure, or sleep apnoea. For South Asian, Chinese, Black African, or Black Caribbean adults, lower thresholds (BMI 27.5+) may apply. Use our BMI calculator above to check your current BMI.
Can I get Mounjaro without going through my GP?
Yes. The private route allows you to access Mounjaro directly through an online consultation with a prescriber, without a GP referral. However, you must still be clinically eligible and pass the prescriber's assessment.
How long does the Mounjaro prescription process take?
NHS timelines vary by region—waiting times can range from weeks to many months. Private route is typically faster: you complete an online consultation within days, and if approved, your prescription is usually dispensed within 1–2 weeks.
What happens after I'm prescribed Mounjaro—do I need ongoing monitoring?
Yes. Whether NHS or private, your prescriber will monitor your progress, side effects, and response to treatment. You'll likely start on a 2.5 mg dose and increase gradually each week until reaching your maintenance dose. Regular check-ins are important for safety and effectiveness.
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.