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 Max Dose in the UK — Cost and Access
Mounjaro's maximum dose is 15mg once weekly. This is the highest strength available in the UK, typically reached after a gradual dose titration starting from 2.5mg. Most people take between 4–16 weeks to reach the maximum dose, with increases every 4 weeks if tolerated. The cost and access route for Mounjaro vary significantly depending on whether you pursue NHS or private prescription options. Understanding both pathways helps you make an informed decision about availability and affordability.
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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.
Mounjaro Max Dose and Private Prescription Costs in the UK
Mounjaro is available in the UK through private prescription as a branded KwikPen device, with costs varying by dose and provider. Private costs typically range from £129–£320 per month depending on your dose level and the pharmacy used. The maximum 15mg dose is usually among the most expensive options available. Unlike lower doses, reaching 15mg requires commitment to the full titration schedule—typically 16–20 weeks—so upfront costs should be considered alongside the expected timeline. Prescription tirzepatide (the generic name) may be slightly cheaper than the branded Mounjaro at some providers, but all require a valid UK prescription from a licensed healthcare professional. Dose titration costs must be factored in: you cannot skip to 15mg immediately; you must follow the approved escalation schedule, meaning you'll pay for multiple dose levels before reaching the maximum.
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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 Access for Mounjaro in the UK
NHS access: Mounjaro is approved by NICE for use within NHS specialist tier 3/4 weight management services, but you cannot request it directly from your GP. You must be referred to a specialist weight management service, which involves a waiting list—typically several months to over a year in many areas depending on your region. NHS prescribing is free at point of use once approved.
Private access: You can obtain a prescription within days through a GPhC-registered online pharmacy following a remote clinical assessment. No NHS referral is needed. An online consultation with a UK-licensed prescriber takes 10–20 minutes; if approved, your prescription is issued and dispensed by the pharmacy. This route is faster but requires payment for each dose level during titration.
- 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.
What is Mounjaro's maximum dose and how long does it take to reach it?
The maximum dose is 15mg once weekly. Dose titration takes 16–20 weeks on average, starting at 2.5mg with 4-week increments. You cannot skip doses—each level must be tolerated for at least 4 weeks. Total cost includes all intermediate doses, not just the final 15mg strength.
How much does Mounjaro cost in the UK on private prescription?
Private costs range from approximately £129–£320 monthly depending on dose strength and provider. The 15mg maximum dose sits at the higher end. You'll pay for multiple dose levels during titration, so budget for several months of escalating costs before reaching maximum strength.
Can I get Mounjaro on the NHS in the UK?
Yes—NICE approved tirzepatide for NHS specialist weight management services. However, access is through tier 3/4 referral only, not from your GP directly. Waiting lists vary by region and can exceed one year. Once approved, it's free. Private prescription offers faster access.
What's the difference between NHS and private Mounjaro prescription in the UK?
NHS requires GP referral to specialist services and involves waiting lists, but is free. Private prescription is faster (days, not months), requires an online clinical assessment, and costs £129–£320 monthly. Both require prescription from a UK-licensed prescriber and follow the same dose titration protocol.
Can I switch from a lower Mounjaro dose to 15mg quickly?
No. The dose titration protocol is fixed: 2.5mg (weeks 1–4), 5mg (weeks 5–8), 7.5mg (weeks 9–12), 10mg (weeks 13–16), 12.5mg (weeks 17–20), then 15mg (week 21+). Each dose requires minimum 4 weeks before escalation. Faster titration increases side effect risk and is not recommended.
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.