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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Starting Mounjaro in the UK — How to Access & Cost Guide
If you're considering starting Mounjaro (tirzepatide) for weight management in the UK, you'll have two main routes: NHS specialist services or private prescription. Access, costs, and timelines differ significantly between the two pathways. This guide explains how to get started, what Mounjaro costs in the UK, eligibility requirements, and what to expect during your initial dose titration. Use our GLP-1 weight loss calculator to explore potential outcomes alongside this access information.
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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.
Private Prescription Cost & Access in the UK
Private Mounjaro prescriptions are available through GPhC-registered online pharmacies following a clinical assessment with a UK-licensed prescriber. Monthly costs range from approximately £129 to £280 depending on your starting dose.
- 2.5 mg starting dose: typically £129–£150/month
- 5 mg maintenance dose: typically £150–£180/month
- 10–15 mg higher doses: typically £200–£280/month
Costs vary by provider. The online consultation itself is usually free or £15–£30. You'll receive a KwikPen containing 4 weeks of doses. Private access means you can start without NHS referral or waiting lists—typically within 1–2 weeks of your assessment. Compare this route using our BMI calculator to confirm your eligibility before booking a consultation.
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 Access vs Private — What's the Difference?
NHS route: NICE has approved tirzepatide (Mounjaro) through specialist tier 3/4 weight management services. Access is via GP referral to your local integrated care board (ICB) weight management service. NHS Mounjaro is free once prescribed, but waiting lists vary widely—from months to over a year in many regions. Not all ICBs have equal availability. You'll need a BMI of 30+ (or 27+ with weight-related health conditions) and typically require attendance at weight management programmes.
Private route: Faster access (1–2 weeks), no waiting lists, no NHS referral needed. You pay per dose. Both routes require clinical assessment to confirm suitability. Most people access Mounjaro privately in the UK due to NHS waiting times.
- 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 privately in the UK per month?
Private Mounjaro costs range from approximately £129 to £280 per month depending on your dose. Starting doses (2.5–5 mg) cost around £129–£180/month, while higher maintenance doses (10–15 mg) cost £200–£280/month. Prices vary by provider. The KwikPen contains 4 weeks of doses.
Can I get Mounjaro on the NHS in the UK?
Yes, NICE has approved tirzepatide through NHS specialist weight management services. Access is via GP referral to your local ICB tier 3/4 service. Mounjaro is free on NHS, but waiting lists are significant—often several months to over a year. Eligibility requires BMI 30+ (or 27+ with weight-related health conditions). Availability varies by region.
What's the difference between NHS and private Mounjaro access?
NHS Mounjaro is free but involves long waiting lists and GP referral; private is faster (1–2 weeks), costs £129–£280/month, and requires no NHS referral. Both require clinical assessment. Private access is more common due to NHS availability constraints.
What happens during the dose titration period when starting Mounjaro?
You start on 2.5 mg weekly for 4 weeks, then increase by 2.5 mg every 4 weeks (5 mg, 7.5 mg, 10 mg, 12.5 mg, 15 mg maximum). Each dose adjustment is gradual to allow your body to adjust and monitor side effects. Most people stabilise on 10–15 mg, though some benefit from lower doses.
Do I need a prescription to get Mounjaro in the UK?
Yes, Mounjaro is prescription-only in the UK. Private access requires a UK-licensed prescriber to assess you through an online consultation and issue a prescription if appropriate. NHS access requires a GP referral. Individual clinical assessment is always required before prescribing.
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.