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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Mounjaro Doses: UK Cost and Access
Mounjaro (tirzepatide) is available in the UK through both NHS specialist services and private online prescribing, with doses ranging from 2.5 mg to 15 mg administered once weekly via a pre-filled KwikPen device. Access routes, costs, and timelines differ significantly depending on whether you're obtaining treatment through the NHS or privately. This guide explains UK pricing, eligibility, and how to access Mounjaro in both sectors.
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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 Mounjaro Costs and Access in the UK
Private tirzepatide (Mounjaro) prescriptions in the UK typically cost between £150 and £320 per month depending on your dose and the online provider. Costs generally increase with higher doses — a starting 2.5 mg dose is usually at the lower end of this range, whilst the maximum 15 mg dose sits at the higher end. Private prescribing is available through GPhC-registered online pharmacies following an online clinical assessment with a UK-licensed prescriber, usually lasting 15–30 minutes. You don't require a GP referral for private access, and prescriptions can be issued the same day or within 48 hours if clinically appropriate. Each KwikPen contains four weekly doses (one month's supply), and you'll need a new prescription every month. Unlike NHS access, private treatment is not subject to regional waiting lists, making it significantly faster to start if you meet clinical eligibility criteria. Consider using our free GLP-1 weight loss calculator to estimate potential weight loss at different doses before committing to treatment.
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 vs Private: Which Route Suits You?
NHS access is free at point of use but requires referral from your GP to a tier 3 specialist weight management service. Waiting times vary dramatically by region — some areas have waiting lists exceeding 12–18 months, whilst others may have capacity within 3–6 months. Once assessed by the specialist team, if Mounjaro is appropriate, you'll receive it free on prescription. Private access costs money but is faster and doesn't require NHS referral. You complete an online clinical questionnaire, have a brief video or telephone consultation with a prescriber, and receive your prescription within 24–48 hours if approved. The online consultation process includes review of your medical history, current medications, BMI (check your BMI with our free calculator above), and weight-related health conditions to ensure tirzepatide is safe for you. Private treatment is ideal if you have a high BMI or weight-related health issues and want to start quickly.
- 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 in the UK?
Mounjaro is completely free on the NHS if prescribed through a tier 3 specialist weight management service. However, access is through specialist referral only, not from your GP directly, and waiting times vary significantly by region — sometimes 6–18 months depending on your local integrated care board (ICB) capacity.
What's the typical cost of private Mounjaro prescriptions per dose?
Private tirzepatide prescriptions typically cost £150–£320 per month depending on your dose. A 2.5 mg starting dose is usually around £150–£180, whilst a 15 mg maximum dose may cost £280–£320. Each prescription covers four weekly injections (one month).
Do I need a GP referral to access private Mounjaro?
No. Private Mounjaro prescriptions are available directly through online consultations with UK-licensed prescribers without NHS referral. You complete an online health questionnaire, have a brief clinical assessment, and receive a prescription if appropriate — usually within 24–48 hours.
How long does an online consultation for Mounjaro take?
Most online consultations take 15–30 minutes. You'll answer detailed health questions, discuss your weight loss goals and medical history, and the prescriber will assess whether tirzepatide is safe and appropriate for you based on your BMI and any weight-related health conditions.
Can I switch from NHS to private Mounjaro, or vice versa?
Switching between routes is possible but typically requires stopping one course and starting another through the new provider. There's no official pathway for direct transfers between NHS and private providers, so discuss any transition plans with your current prescriber or GP first.
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.