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 Access Mounjaro in the UK — Prescribing Guidelines
Mounjaro (tirzepatide) is a prescription-only weight management injection available in the UK through both NHS specialist services and private prescribing routes. Access depends on your eligibility, which is assessed based on BMI and weight-related health conditions. This guide explains the UK prescribing pathway, how costs compare between NHS and private options, and what the online consultation process involves. Understanding your options helps you make an informed decision about pursuing tirzepatide treatment.
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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.
Private Prescription Costs and Access in the UK
Private Mounjaro prescriptions are available through GPhC-registered online pharmacies following a clinical assessment with a UK-licensed prescriber. Costs typically range from £129 to £320 per month depending on your dose, with variation between providers. The starting dose (2.5 mg) is generally less expensive than higher maintenance doses (10–15 mg). You do not require an NHS referral for private access — the entire process is completed online. Most private providers offer subscription models, allowing you to order monthly or skip weeks as needed. Payment is typically required upfront, though some providers offer payment plans. Private access is significantly faster than NHS routes, with prescriptions often issued within 24–72 hours of your assessment. Costs do not include delivery, which is usually £3–£8 per order. Always check whether your chosen provider offers ongoing prescriber support and whether dose adjustments are included in the stated price.
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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.
NHS vs Private Routes and What to Expect
NHS access to Mounjaro is through tier 3 specialist weight management services, typically following a GP referral. NICE has approved tirzepatide for NHS use, but availability varies significantly by region and NHS Integrated Care Board (ICB). Waiting lists can range from several months to over a year in some areas. Private access involves an online consultation where a prescriber assesses your medical history, current medications, and weight management goals. You'll be asked about contraindications including pregnancy plans, pancreatitis history, and gallbladder problems. If approved, a prescription is issued and dispensed by a pharmacy. The entire private process takes 1–3 business days from assessment to delivery. Both routes require the same clinical assessment criteria — BMI ≥30 or BMI 27–29.9 with weight-related health conditions.
- 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.
How much does Mounjaro cost on the NHS?
Mounjaro is available free on the NHS through tier 3 specialist weight management services, but access is limited and varies by region. Many areas have long waiting lists. Your GP can refer you to your local specialist service to check eligibility and current waiting times.
What's included in private Mounjaro costs?
Private costs typically cover the prescription and medication only. Delivery fees (usually £3–£8) are added separately. Some providers include one follow-up prescriber consultation, whilst others charge extra for dose adjustments. Always confirm what's included before purchasing.
How long does the private online assessment take?
The online consultation usually takes 10–20 minutes. You complete a health questionnaire, have a video or phone call with a prescriber, and receive a decision within 24 hours. If approved, your prescription is sent to the pharmacy for dispensing within 1–2 business days.
Can I switch from NHS to private Mounjaro?
Yes, you can access private Mounjaro independently at any time, whether or not you're on an NHS waiting list. However, inform your GP if you're receiving treatment privately, as they should be aware of all medications you're taking.
What happens if I'm not eligible for private Mounjaro?
If a prescriber assesses you as ineligible during a private consultation, they will explain why — commonly due to medical contraindications or BMI below threshold. Your GP can discuss alternative weight management options or refer you to NHS specialist services.
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.