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
What Weight Do You Need to Be for Mounjaro in the UK?
To access Mounjaro (tirzepatide) in the UK, you need to meet specific weight and health criteria — not just any weight qualifies. Whether you can get this prescription weight loss injection depends on your BMI, any weight-related health conditions, and whether you choose NHS or private access routes. This guide explains the eligibility requirements, costs, and how the online prescription process works for UK adults considering this weekly weight loss injection.
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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.
Mounjaro UK Cost and Private Prescription Access
Private prescription cost context: Mounjaro is available through UK-registered online pharmacies following an online clinical assessment. Prices vary by dose and provider, typically ranging from £129 to £320+ per month depending on whether you're starting at a lower dose (2.5–5 mg) or at maintenance doses (10–15 mg).
- Starting doses (2.5–5 mg) generally cost £129–£180 per month
- Mid-range doses (7.5–10 mg) typically £180–£240 per month
- Higher maintenance doses (12.5–15 mg) may cost £240–£320+ per month
Each KwikPen contains a 4-week supply (4 injections). Prices reflect a single pen and may vary by provider. The prescriber will assess your suitability during an online consultation — this is not a assured outcome. Mounjaro is prescription-only and requires clinical assessment before dispensing.
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 Access Routes for Mounjaro
NHS route: Mounjaro is available through NHS specialist tier 3/4 weight management services, but access requires GP referral and can involve long waiting lists — currently months to years in many regions depending on your integrated care board (ICB) area. Private route: Skip the NHS queue by consulting a UK-licensed prescriber online. After a clinical assessment, a prescription may be issued and dispensed by a GPhC-registered pharmacy without NHS referral. Private access is faster but costs are not covered by the NHS. Use our free BMI calculator to check your current BMI and understand your starting point, then discuss your options — NHS or private — with your GP or a licensed 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 BMI do I need to qualify for Mounjaro in the UK?
You need a BMI of 30 or above (obesity), or 27–29.9 (overweight) with at least one weight-related health condition like type 2 diabetes, high blood pressure, or cardiovascular disease. For South Asian, Chinese, Black African, or Black Caribbean adults, lower thresholds apply — eligibility may start at BMI 27.5+. Use our BMI calculator to find your current BMI instantly.
How much does Mounjaro cost privately in the UK?
Private Mounjaro costs range from approximately £129 to £320+ per month depending on your dose. Starting doses (2.5–5 mg) are typically cheaper than higher maintenance doses (10–15 mg). Each KwikPen is a 4-week supply. Prices vary by provider, and this cost is not covered by NHS prescription charges.
Can I get Mounjaro on the NHS?
Yes, Mounjaro is available through NHS specialist weight management services following GP referral to tier 3/4 services. However, NHS access varies significantly by region, and waiting lists can be very long. Private prescription access is often faster if you meet clinical criteria and can afford the cost.
How long does the online consultation take for a private Mounjaro prescription?
Online consultations typically take 10–20 minutes. You'll be asked about your medical history, current medications, weight, and health goals. A UK-licensed prescriber will assess your suitability. If approved, a prescription is issued to a GPhC-registered pharmacy for dispensing — usually within 24–48 hours.
Is Mounjaro the same as a weekly weight loss injection I've heard about?
Mounjaro (tirzepatide) is a prescription-only weekly weight loss injection that works as a dual GIP and GLP-1 receptor agonist. It's one of several weekly weight loss injections available in the UK — Wegovy (semaglutide) is another. Both require prescription and clinical assessment. Try our GLP-1 weight loss calculator to explore potential outcomes at different doses.
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.