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 Do I Get Mounjaro in the UK?
Mounjaro (tirzepatide) is available in the UK through two main routes: specialist NHS weight management services and private online prescribing. NICE has approved tirzepatide for use within NHS tier 3 services, though access varies significantly by region and waiting times can be lengthy. Private access is faster and available without NHS referral, though it involves costs. This guide explains both pathways, eligibility criteria, and what to expect at each stage of getting a Mounjaro prescription.
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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.
Getting Mounjaro Through the NHS
The NHS tier 3 specialist weight management pathway is the primary route for accessing Mounjaro on the health service. You'll need referral from your GP to a specialist tier 3 or tier 4 weight management service in your area. Your GP will assess whether referral is appropriate based on your BMI and health conditions.
- BMI of 30 kg/m² or above (obesity)
- BMI of 27–29.9 kg/m² with weight-related health conditions (type 2 diabetes, high blood pressure, sleep apnoea, cardiovascular disease)
- Lower thresholds may apply if you're of South Asian, Chinese, Black African, or Black Caribbean heritage
Once referred, you'll be assessed by the specialist team, who will determine whether Mounjaro is suitable and manage your dose titration from 2.5 mg up to 15 mg. NHS availability is limited and regional — some areas have longer waiting lists than others. Speak to your GP about local availability and what to expect.
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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.
Getting Mounjaro Through Private Prescription
Private access is faster and doesn't require NHS referral. You can obtain a Mounjaro prescription from a UK-licensed prescriber via an online clinical consultation with a GPhC-registered pharmacy. The process typically takes a few days from consultation to prescription.
Private prescribers will assess your suitability based on your BMI, weight-related health conditions, current medications, and medical history. Once approved, your prescription is dispensed by a pharmacy. Costs range from approximately £129–£320 per month depending on your dose and the provider. Private prescribing is ideal if NHS waiting lists are long or you prefer faster access, though you'll bear the full cost of medication.
- 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.
Can my GP prescribe Mounjaro directly?
In most cases, no. Your GP will refer you to a specialist tier 3 weight management service, which is where Mounjaro prescriptions are typically initiated within the NHS. However, some specialist GPs may initiate it — ask your GP about local pathways. Private GPs and online prescribers can prescribe Mounjaro directly if you meet eligibility criteria.
How long does it take to get Mounjaro on the NHS?
This varies significantly by region. Some specialist services have waiting lists of several months or longer, while others may be shorter. Contact your local tier 3 service for their current waiting times. Private access typically takes 3–7 days from consultation to prescription delivery.
What's the difference between Mounjaro on the NHS and from a private prescription?
The medication is identical. The main differences are the waiting time (NHS can be longer), cost (NHS is free, private costs £129–£320/month), and pathway (NHS requires GP referral to specialist services, private requires an online clinical assessment). Dose titration and monitoring follow similar principles in both routes.
Do I need to meet specific BMI or health criteria to get Mounjaro?
Yes. You'll need a BMI of 30 kg/m² or above, or 27–29.9 kg/m² with at least one weight-related health condition like type 2 diabetes, high blood pressure, or sleep apnoea. Lower thresholds apply if you're of South Asian, Chinese, Black African, or Black Caribbean heritage. Your GP or private prescriber will assess whether you meet these criteria.
Can I use the NHS and then switch to private, or vice versa?
Switching between NHS and private is possible but should be managed carefully. If you're prescribed Mounjaro through one route, inform any new prescriber about your current treatment. Never overlap NHS and private prescriptions. Your prescriber will coordinate the transition and manage dose continuity safely.
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.