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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What Is The Mounjaro Maintenance Dose In The UK?
The maintenance dose of Mounjaro (tirzepatide) is 15mg once weekly for most UK adults — the maximum recommended dose. However, many people stabilise on lower doses like 5mg, 10mg, or 12.5mg depending on their individual response and tolerance. This guide explains Mounjaro dose progression, typical maintenance doses, UK prescription costs, and how to access this weight management injection through NHS specialist services or private prescription routes.
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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 Dose Progression And Maintenance In The UK
Mounjaro (tirzepatide) uses a dose titration schedule — you start low and increase gradually every 4 weeks until reaching your maintenance dose. The standard UK progression is:
- Weeks 1–4: 2.5mg (starter dose)
- Weeks 5–8: 5mg
- Weeks 9–12: 7.5mg
- Weeks 13–16: 10mg
- Weeks 17–20: 12.5mg
- Week 21+: 15mg (maximum maintenance dose)
Not everyone reaches 15mg — your prescriber may recommend staying on a lower maintenance dose if you're experiencing good weight loss results and tolerating the dose well. Clinical trials showed that doses of 5mg, 10mg, and 15mg all produced meaningful weight loss, with higher doses producing greater average results. Your GP or prescriber will assess what's right for you based on your response and any side effects.
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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
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Mounjaro Cost And Access Routes In The UK
NHS route: Available through specialist tier 3/4 weight management services following GP referral. NICE has approved tirzepatide for NHS use, but access varies significantly by region and waiting lists can be lengthy. Once prescribed, NHS costs are covered by your prescription charge (or free if eligible).
Private route: Available through GPhC-registered online prescribing services. Costs typically range from £129–£320 per month depending on your maintenance dose and provider. A 15mg Mounjaro KwikPen (4 weeks supply) usually costs more than a 5mg or 10mg pen at the same provider. Private prescription requires an online clinical assessment with a UK-licensed prescriber — no NHS referral needed, but you must meet eligibility criteria (BMI ≥30 or ≥27 with weight-related health conditions).
- 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.
Is 15mg the maintenance dose everyone reaches on Mounjaro?
No. While 15mg is the maximum dose, many people maintain effective weight loss on 5mg, 10mg, or 12.5mg. Your prescriber will recommend a maintenance dose based on your individual response, weight loss results, and how well you tolerate the injection. There's no requirement to reach 15mg.
How long does it take to reach maintenance dose on Mounjaro?
The standard titration schedule takes approximately 20 weeks (5 months) to reach 15mg, starting from 2.5mg. You increase by one dose level every 4 weeks. If your prescriber recommends a lower maintenance dose, you'll reach it sooner.
Can I access Mounjaro on the NHS for weight management in the UK?
Yes, NICE has approved tirzepatide (Mounjaro) for NHS use in specialist weight management services. However, availability varies by region and waiting lists are often long. You'll need to be referred to a tier 3 or tier 4 weight management service by your GP. Private prescription routes don't require an NHS referral and are typically faster.
What does a private Mounjaro prescription cost per month in the UK?
Private costs typically range from £129–£320 per month depending on your maintenance dose. A higher dose (like 15mg) costs more than a lower maintenance dose at the same provider. Prices vary between providers, so it's worth comparing. This is separate from any online consultation fee your prescriber may charge.
How do I know if my maintenance dose of Mounjaro is working?
Your prescriber will monitor your weight loss progress, appetite changes, and any side effects. After 12 weeks on your maintenance dose, you should review results with your prescriber to confirm whether your current dose is producing acceptable weight loss or whether adjustment is needed. ```
Ready to take control of your weight loss journey?
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