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 Chart — UK Doses and Weight Loss Guide
Mounjaro (tirzepatide) is a prescription-only weight management injection available in the UK. This chart shows the standard weekly doses prescribed in the UK, from the initial 2.5mg starting dose up to the 15mg maximum. Understanding the dose progression, how tirzepatide works as a dual GIP and GLP-1 receptor agonist, and what clinical trial data shows about weight loss outcomes can help you understand what to expect if prescribed this medication. Always consult your GP or a licensed prescriber about your individual eligibility and suitability.
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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 UK Dose Chart and Titration Schedule
Standard Mounjaro doses in the UK follow a four-week titration schedule. You begin on 2.5mg once weekly for the first four weeks, then typically increase to 5mg for weeks 5–8, then 7.5mg for weeks 9–12, continuing to escalate in 2.5mg increments every four weeks until reaching your effective maintenance dose or the 15mg maximum.
- Week 1–4: 2.5mg once weekly (starting dose)
- Week 5–8: 5mg once weekly
- Week 9–12: 7.5mg once weekly
- Week 13–16: 10mg once weekly
- Week 17–20: 12.5mg once weekly
- Week 21+: 15mg once weekly (maximum dose)
Each KwikPen contains four weekly doses. Your prescriber will assess whether you need to continue escalating or remain at a particular dose based on your weight loss response and tolerance. The dual GIP and GLP-1 mechanism may help regulate appetite and support feeling fuller after smaller meals, though results vary significantly between individuals.
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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.
Expected Weight Loss and Clinical Trial Data
Clinical trial data from the SURMOUNT-1 trial showed that at week 72, participants achieved average weight loss of approximately 15% of body weight at the 5mg dose, 19.5% at 10mg, and 20.9% at the 15mg dose. These outcomes were achieved alongside a reduced-calorie diet and increased physical activity. It is important to note that individual results vary significantly — some people experience greater weight loss, while others experience more modest outcomes. Use our free GLP-1 weight loss calculator to explore potential weight loss projections at different doses, and our BMI calculator to understand your starting point and healthy weight range for your height.
Mounjaro Eligibility and How to Access in the UKAdults may be eligible for Mounjaro if they have a BMI of 30 or above, or 27–29.9 with at least one weight-related health condition such as type 2 diabetes, high blood pressure, or cardiovascular disease. For South Asian, Chinese, Black African, or Black Caribbean adults, lower BMI thresholds may apply. Mounjaro is available through NHS specialist tier 3 weight management services (with regional variation in access and waiting lists) or through private prescribing following an online clinical assessment with a UK-licensed prescriber. A clinical assessment is always required before prescription — your prescriber will evaluate your medical history, current medications, and suitability for this treatment.
- 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 and how does it work?
Mounjaro (tirzepatide) is a once-weekly injection that activates two hormone pathways — GIP and GLP-1 — to help regulate appetite, reduce food cravings, and support feeling fuller. It is prescription-only and licensed for weight management in UK adults who meet eligibility criteria.
How quickly do you increase Mounjaro doses?
Doses increase by 2.5mg every four weeks, starting at 2.5mg for weeks 1–4, then 5mg, 7.5mg, 10mg, 12.5mg, and up to 15mg maximum. Your prescriber will decide when to increase based on your response and tolerability.
What weight loss can I expect with Mounjaro?
Clinical trials showed average weight loss of 15–21% of body weight, though results vary significantly between individuals. Your personal outcome depends on your starting weight, adherence to reduced-calorie diet, physical activity, and how your body responds to the medication.
Am I eligible for Mounjaro in the UK?
You may be eligible if your BMI is 30 or above, or 27–29.9 with weight-related health conditions like diabetes or high blood pressure. Lower thresholds apply for certain ethnic backgrounds. A prescriber will assess your individual eligibility following a clinical assessment.
What is the difference between Mounjaro and Wegovy?
Mounjaro (tirzepatide) is a dual GIP and GLP-1 agonist with a 15mg maximum dose. Wegovy (semaglutide) is a GLP-1-only agonist with a 2.4mg maximum dose. Clinical trial data suggests Mounjaro may produce slightly greater average weight loss, though individual results vary and both require prescription and clinical assessment.
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.