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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Weight Loss Jab Mounjaro: NHS vs Private Access in the UK
Mounjaro (tirzepatide) is a prescription-only weekly weight loss injection available in the UK through both NHS and private routes. Access and cost vary significantly depending on which pathway you choose. The NHS offers access through specialist weight management services, whilst private prescription provides faster access without waiting lists. Understanding both options helps you find the right route for your situation. This guide explains eligibility, costs, and how to access Mounjaro in the UK.
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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 and Access in the UK
Private prescription Mounjaro costs in the UK typically range from £129 to £320 per month, depending on your dose and the provider. Lower doses (2.5–5 mg) cost less, whilst maximum doses (15 mg) cost more. Each KwikPen contains four weekly injections, so monthly costs represent a 4-week supply. Private access is available without NHS referral through GPhC-registered online pharmacies following a brief online clinical assessment with a UK-licensed prescriber. This route offers faster access — often within days — compared to NHS waiting lists. Common doses and approximate monthly costs: 5 mg around £129–£180, 10 mg around £200–£260, 15 mg around £280–£320. Private costs are not covered by the NHS, so you pay the full amount. Some people use private prescription to start treatment whilst awaiting NHS specialist assessment.
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: Which Route Is Right?
NHS access to Mounjaro is through tier 3 specialist weight management services, not routine GP prescription. You need GP referral to a specialist service in your area. NICE has approved tirzepatide for use within NHS weight management pathways, but availability and waiting times vary significantly by region and ICB funding. Some areas have waiting lists of several months to over a year. Private access is faster but costs more. NHS is free at point of use but requires specialist referral and meeting local service criteria. Many people choose private prescription for rapid access whilst also being referred to NHS services, then switch to NHS once assessed. Your GP can help you understand local NHS options and referral timescales.
- 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?
Private Mounjaro costs range from approximately £129–£320 per month depending on your dose. Lower starting doses (2.5–5 mg) cost around £129–£180 monthly, whilst maximum doses (15 mg) cost £280–£320. Costs cover a 4-week supply (one KwikPen with four weekly injections). Prices vary slightly between providers but are similar across the market.
Can I get Mounjaro on the NHS?
Yes. NICE has approved tirzepatide (Mounjaro) for use within NHS specialist weight management services. Access is through tier 3 weight management clinics via GP referral, not routine GP prescription. Eligibility requires a BMI of 30 or above, or 27–29.9 with weight-related health conditions. NHS availability and waiting times vary significantly by region.
How long does NHS waiting list for Mounjaro take?
NHS waiting times vary by region and local ICB funding. Some areas offer assessment within weeks, whilst others have waiting lists of 6–18 months or longer. Contact your local weight management service or ask your GP about current waiting times in your area. Private prescription offers faster access if you need treatment urgently.
What is the online consultation process for private Mounjaro?
Most private routes involve: (1) completing an online medical questionnaire, (2) brief video or telephone consultation with a UK-licensed prescriber, (3) prescription issued if clinically appropriate, (4) KwikPen dispensed by a GPhC pharmacy and delivered to your address. The whole process typically takes 24–48 hours. You'll need to provide medical history and current medications.
Is Mounjaro better than other weekly weight loss injections like Wegovy?
Mounjaro (dual GIP/GLP-1 agonist) and Wegovy (GLP-1 agonist only) work differently. Clinical trials showed Mounjaro achieved average weight loss of 15–21% body weight, whilst Wegovy achieved around 15%. Results vary individually. Your prescriber can advise which is more suitable based on your health profile. Both are prescription-only and require clinical assessment.
Ready to take control of your weight loss journey?
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