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 a Mounjaro Prescription in the UK
Getting a Mounjaro prescription in the UK involves two distinct routes: NHS specialist services or private online prescribing. The route you choose depends on your eligibility, local NHS availability, and budget. Mounjaro (tirzepatide) is a prescription-only weight loss injection that requires a clinical assessment before being prescribed. This guide explains how each route works, what costs to expect, and what happens next. Our GLP-1 weight loss calculator can help you understand potential outcomes at different doses.
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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 vs Private Routes for Mounjaro Prescription
NHS route: Mounjaro is approved by NICE for use within specialist weight management services (tier 3/4). To access it via the NHS, you must first speak to your GP about a referral to your local weight management service. NICE recommends tirzepatide for adults with a BMI of 30 or above, or BMI 27–29.9 with weight-related health conditions such as type 2 diabetes, high blood pressure, or cardiovascular disease. However, NHS availability varies significantly by region — some areas have long waiting lists (6–18 months), while others may not offer it yet. Access depends on your Integrated Care Board (ICB) commissioning decisions.
Private route: Private prescription is available immediately through GPhC-registered online pharmacies. You complete an online health questionnaire, a UK-licensed prescriber reviews your information, and if approved, a prescription is issued and the medication is dispensed. Private prescriptions are faster but require payment upfront. There are no waiting lists, and eligibility is assessed individually without geographic restrictions.
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 Mounjaro Costs and What to Expect
Private Mounjaro prescriptions cost between approximately £129–£320 per month depending on your starting dose and provider. Initial doses (2.5 mg) are typically at the lower end; maintenance and higher doses (10–15 mg) cost more. Most providers require a new online assessment every 3–6 months to renew your prescription. Costs do not include GP reviews or blood tests that your prescriber may recommend. Some private providers offer payment plans or discounts for upfront payment of multiple months. Always confirm the exact price before starting — costs vary between providers. You can use our BMI calculator to check your starting eligibility, then speak to a prescriber about your personal assessment and pricing.
Online consultation process: Complete a health form with your weight, height, medical history, and current medications. A UK doctor reviews your information within 24 hours. If approved, your prescription is sent to a GPhC pharmacy and your Mounjaro KwikPen is delivered to your home. If not approved, the prescriber will explain why and suggest alternatives. You inject once weekly at home using the pre-filled pen. Regular check-ins with your prescriber (usually online or by phone) monitor your progress and side effects, with dose adjustments every 4 weeks if needed.
- 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 Mounjaro on the NHS?
Yes, but access depends on your local NHS specialist weight management service. NICE has approved tirzepatide for eligible adults. Referral comes from your GP. NHS waiting lists vary from immediate to 18+ months depending on your area. Contact your GP to discuss NHS options in your region.
How much does Mounjaro cost privately in the UK?
Private Mounjaro typically costs £129–£320 per month depending on your dose and provider. Starting doses (2.5 mg) are cheaper; higher maintenance doses (10–15 mg) cost more. Prices vary between providers, so always confirm costs upfront. Some offer payment plans.
What is the difference between Mounjaro and Wegovy?
Mounjaro (tirzepatide) is a dual GIP and GLP-1 receptor agonist. Wegovy (semaglutide) is a GLP-1 agonist only. Clinical trials showed Mounjaro may support slightly greater average weight loss, but individual results vary. Both are prescription-only and available through NHS and private routes.
Do I need ongoing GP support if I use private Mounjaro?
Your prescriber will monitor you, but it's recommended to inform your GP that you're using Mounjaro. Your GP can provide regular health checks and manage any weight-related conditions. Some private providers may recommend blood tests or periodic GP reviews alongside their prescriber assessments.
How long does the online prescription process take?
Most GPhC-registered providers assess your application within 24 hours. If approved, your prescription is issued and sent to a pharmacy. Delivery typically takes 2–5 working days. Private prescriptions are much faster than NHS routes, which can involve months of waiting.
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.