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 Clicks Chart — Understanding Your KwikPen Doses
The Mounjaro KwikPen uses a click-based dosing system that makes it easy to deliver the correct weekly dose. Each click on the pen corresponds to a specific amount of tirzepatide, and understanding how this works helps you use your injection safely and confidently. This guide explains how the click chart relates to your prescribed dose and what to expect at each stage of treatment.
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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.
How the Mounjaro KwikPen Click System Works
The Mounjaro KwikPen is a pre-filled injection device designed for once-weekly dosing. Rather than drawing liquid from a vial, the pen delivers a pre-measured dose with each use. Each KwikPen contains 4 weekly doses — one month's supply.
The click mechanism allows you to select your prescribed dose by turning the dose knob until the correct number appears in the window. Once the correct dose is selected, you inject subcutaneously (under the skin) into the abdomen, thigh, or upper arm. The pen automatically delivers the full dose.
Common injection sites:
- Stomach (abdomen) — most common choice
- Upper thigh — easy to self-inject
- Upper arm — requires assistance
Always rotate your injection site each week to prevent lipohypertrophy (thickened skin tissue at injection sites).
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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.
Mounjaro Dose Progression and Titration Schedule
Mounjaro dose titration follows a gradual escalation pattern over several weeks. You start at a lower dose to allow your body to adjust, then increase every 4 weeks until reaching your maintenance dose.
- Week 1–4: 2.5 mg once weekly (starting dose)
- Week 5–8: 5 mg once weekly
- Week 9–12: 7.5 mg once weekly
- Week 13–16: 10 mg once weekly
- Week 17–20: 12.5 mg once weekly
- Week 21+: 15 mg once weekly (maximum dose)
Your prescriber may keep you on any dose depending on how well it works for you. Not everyone reaches the maximum — some find good results at 5 mg or 10 mg. Use our free GLP-1 weight loss calculator to explore potential outcomes at different doses.
- 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 does each click on the Mounjaro KwikPen deliver?
Each click on the KwikPen corresponds to a specific dose of tirzepatide measured in milligrams (mg). Your prescriber tells you exactly how many clicks to use for your current dose. The pen's dose window shows the selected dose clearly. Always check the window before injecting to confirm you have the correct dose selected.
Why does Mounjaro use a titration schedule rather than starting at the maximum dose?
Gradual dose escalation — titration — allows your body to adjust to the medication and minimises side effects like nausea and vomiting. Starting at 2.5 mg and increasing every 4 weeks gives your digestive system time to adapt. This approach has been shown in clinical trials to improve tolerability and treatment adherence.
Can I stay on a lower Mounjaro dose if it's working well for me?
Yes. Your prescriber may keep you on any dose that is working effectively for you and is well tolerated. Not everyone needs to reach the maximum 15 mg dose. Some people see meaningful weight loss and health improvements at 5 mg or 10 mg. Your prescriber will assess your individual response and may recommend staying at a dose that suits you best.
What should I do if I miss a Mounjaro injection?
If you miss your weekly injection, take it as soon as you remember if it's within 4 days of when you should have had it. Then continue your normal schedule the following week. If more than 4 days have passed, skip that dose and take your next injection on the usual day. Never take two doses close together — allow at least 72 hours (3 days) between injections.
How does Mounjaro compare to Wegovy when it comes to dosing?
Mounjaro (tirzepatide) and Wegovy (semaglutide) are different medications with different mechanisms and dosing schedules. Mounjaro is a dual GIP and GLP-1 agonist with doses ranging from 2.5 mg to 15 mg weekly, while Wegovy is a GLP-1 agonist with doses from 0.25 mg to 2.4 mg weekly. Clinical trials show different average weight loss outcomes — discuss which might suit you with your prescriber.
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.