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 Buy Monjaro in the UK
Monjaro (tirzepatide) is a prescription-only weight loss injection available in the UK through two main routes: NHS specialist services and private prescription. Whether you're eligible, which route suits you, and what it costs depends on your health profile and access to specialist services. This guide explains your options, pricing, and how to start.
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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.
Monjaro Cost and Access Routes in the UK
Accessing Monjaro in the UK depends on whether you use the NHS or private prescription route. NHS access is through specialist tier 3 weight management services — you'll need a GP referral and assessment by a specialist team. Waiting lists vary significantly by region; some areas have 6-month waits, others considerably longer. Private access is faster: you can book an online consultation with a UK-licensed prescriber, receive an assessment, and obtain a prescription without NHS referral.
Private Monjaro costs typically range from £129–£250 per month depending on the dose you require. Starting doses (2.5–5 mg) cost less than maintenance doses (10–15 mg). Each KwikPen contains 4 doses (one month's supply). NHS prescriptions, if dispensed privately, may cost more. Some private providers offer payment plans. Costs are paid by you directly — prescriptions are not typically NHS-funded outside specialist services.
Use our free GLP-1 weight loss calculator to estimate potential results at different Monjaro doses, which may help you decide if this investment is right for you.
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: Which Route Is Right for You?
Choose NHS if: You're eligible (BMI ≥27 with health conditions, or BMI ≥30), want free prescriptions, and can wait for an appointment. Your GP can refer you to your local tier 3 service. Choose private if: You want faster access (2–3 weeks), don't want to involve your GP, or are not yet eligible for NHS services. Private consultations are online; prescriptions are dispensed by GPhC-registered pharmacies.
Both routes require a clinical assessment confirming you're suitable. Private prescribers will ask about your medical history, current medications, and weight loss goals. Your BMI will be calculated using a weight converter or measured in clinic. Neither route assures prescription — clinical suitability is assessed individually.
- 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 I get Monjaro on the NHS for free?
Only through specialist tier 3 weight management services following a GP referral. Eligibility requires a BMI of 30 or above, or 27–29.9 with weight-related health conditions (diabetes, hypertension, sleep apnoea). NHS availability varies by region and waiting times can be long.
How much does private Monjaro cost per month?
Private Monjaro typically costs £129–£250 per month depending on your dose. Starting doses (2.5–5 mg) cost less; maximum doses (15 mg) cost more. Each KwikPen contains 4 weekly doses. Some private providers offer payment plans to spread the cost.
What happens during an online private consultation?
You'll answer health questions about your weight, medical history, medications, and previous weight loss attempts. The prescriber assesses your eligibility and suitability. If approved, a prescription is issued and sent to a GPhC-registered pharmacy for dispensing. Consultations take 15–30 minutes and cost £0–£50 depending on the provider.
Do I need a GP referral for private Monjaro?
No. Private prescribing doesn't require NHS involvement or a GP referral. You can book directly with a private online prescriber. However, informing your GP is recommended so they can monitor your progress and manage any interactions with existing medications.
Is private Monjaro safe if I'm not assessed by the NHS?
Yes, if assessed by a UK-licensed prescriber. Private consultations follow clinical guidelines equivalent to NHS assessment. Prescribers check your medical history, contraindications, and suitability. Both NHS and private routes require proper clinical evaluation before dispensing.
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.