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
Mounjaro in the UK — Your Guide to Access Routes
If you're considering Mounjaro (tirzepatide) for weight management in the UK, you have two main routes: NHS specialist services or private prescription through an online prescriber. Both are legal and available, but with different eligibility criteria, costs, and waiting times. This guide explains how each route works, who qualifies, and how to get started. Use our free BMI calculator above to check if you might meet the eligibility threshold for either route.
10,000+ calculations today · NHS-aligned thresholds · 100% free
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 Access to Mounjaro in the UK
NICE approval: Mounjaro (tirzepatide) is approved by NICE for use within specialist NHS weight management services. However, NHS access is limited and varies significantly by region.
How the NHS route works: You cannot currently obtain Mounjaro directly from your GP. Instead, you must be referred to a tier 3 or tier 4 specialist weight management service through your local Integrated Care Board (ICB). Your GP can make this referral, but availability and waiting times differ greatly across England, Scotland, Wales, and Northern Ireland.
- Tier 3 services are multidisciplinary weight management clinics offering behaviour change support alongside medication
- Tier 4 services include bariatric surgery options
- Referral criteria typically require BMI ≥30, or ≥27 with weight-related health conditions (diabetes, hypertension, sleep apnoea)
- South Asian, Chinese, Black African, and Black Caribbean patients may qualify at lower BMI thresholds (≥27.5)
If approved by the specialist service, Mounjaro is free on the NHS following your clinical assessment. However, waiting times in many regions exceed 12–24 months, and some areas have temporary recruitment freezes.
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 Access to Mounjaro vs NHS Route
Private route: You can obtain a Mounjaro prescription through UK-licensed online prescribers without NHS referral. This requires an online clinical assessment (usually £15–£35) followed by a prescription from a registered doctor. The prescription is then dispensed by a GPhC-registered pharmacy.
Costs: Private Mounjaro costs approximately £129–£199 per month depending on dose and provider. A 2.5 mg starter pen costs around £129; the 15 mg maintenance dose costs £179–£199 monthly.
Key differences: Private access is faster (assessment to prescription within days) but costs apply. NHS access is free but involves specialist referral and significant waiting lists. Both require an appropriate clinical assessment and ongoing prescriber support. Try our free GLP-1 weight loss calculator to project potential results with tirzepatide at different doses, helping you decide if treatment is right for you.
- 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 my GP prescribe Mounjaro directly in the UK?
Not currently. Mounjaro is prescribed through NHS tier 3 specialist weight management services following referral from your GP, or through private online prescribers. Your GP cannot issue a direct NHS prescription for Mounjaro, though they can refer you to the specialist service in your area.
What is the tirzepatide dose titration schedule?
Mounjaro (tirzepatide) starts at 2.5 mg weekly, increasing every 4 weeks: 2.5 mg (weeks 1–4), 5 mg (weeks 5–8), 7.5 mg (weeks 9–12), 10 mg (weeks 13–16), 12.5 mg (weeks 17–20), and 15 mg (week 21+). Your prescriber monitors your response and side effects before each escalation.
How long are NHS waiting lists for Mounjaro?
NHS waiting times vary significantly by region (ICB), ranging from 12–24+ months in many areas. Some services have temporary recruitment freezes. Contact your local weight management service for current waiting times, or ask your GP to find out during referral.
Is Mounjaro weight loss injection available through the NHS at all?
Yes, Mounjaro is NICE-approved and available through NHS tier 3 specialist services, but availability is limited and depends on your local ICB and referral criteria. Private access is generally faster. Compare with our BMI calculator to confirm eligibility before pursuing either route.
What makes Mounjaro different from Wegovy for UK patients?
Mounjaro (tirzepatide) is a dual GIP and GLP-1 receptor agonist, while Wegovy (semaglutide) is GLP-1 only. Mounjaro may offer slightly greater average weight loss in clinical trials (~21% vs ~15%). Both are prescription-only and available through NHS and private routes in the UK, with similar eligibility criteria.
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.