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
Free tracker included with every download this week
How Many Clicks in a Mounjaro 5mg Pen?
A Mounjaro 5mg dose requires two clicks on the KwikPen injection device to dispense the full dose. The Mounjaro KwikPen is designed with a distinctive clicking mechanism that indicates each dose increment, making it straightforward for patients to deliver their weekly injection at home. Understanding how the pen works is essential for accurate dosing and confident self-injection.
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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.
Understanding the Mounjaro KwikPen Click Mechanism
The Mounjaro KwikPen uses a colour-coded dose indicator and audible clicking system to help patients dial and confirm their prescribed dose. Each click corresponds to 0.1 mg of tirzepatide. For a 5mg dose, you would dial the pen until the dose selector stops at the 5mg marking, which requires rotating the dial two full rotations (20 clicks total) to reach 5mg from the starting position. However, the critical thing to understand is that you only inject once the correct dose is dialled — the clicks are not individual injections, but rather incremental dose selections.
- Each click = 0.1 mg dose increment
- 5mg dose = dial to the 5mg line on the pen
- The pen will click and stop at each 0.5 mg interval for easier reading
- Always check your dose window matches your prescribed dose before injecting
- Inject once, when the correct dose is displayed
The design makes it nearly impossible to accidentally inject an incorrect dose — the pen simply will not operate unless the dial is set correctly and the injection button is pressed.
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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.
Correct Mounjaro 5mg Injection Technique
Once you've dialled your 5mg dose on the Mounjaro KwikPen, hold the pen with the needle pointing downward and insert the needle into your chosen injection site (stomach, thigh, or upper arm). Press the injection button firmly and hold for 3 seconds — you'll hear and feel a click confirming the dose is being delivered. The entire injection takes only a few seconds. Always rotate your injection site weekly to avoid lipohypertrophy (tissue thickening). Use our free GLP-1 weight loss calculator to track your expected progress across different Mounjaro doses, and refer to your patient information leaflet or GP if you're unsure about your technique.
- 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 happens if I dial the wrong dose on my Mounjaro pen?
If you dial an incorrect dose, simply rotate the dial back to your prescribed dose shown in the dose window. The pen will not inject unless you press the button. If you've already injected an incorrect dose, contact your prescriber or pharmacist immediately for guidance — do not attempt to correct with a second injection.
Does each click equal one full injection?
No. The clicks are dose increments (0.1 mg each), not separate injections. You dial to your full prescribed dose (e.g., 5mg) and then inject once. The multiple clicks simply help you dial the correct total dose accurately.
Can I use a Mounjaro pen after the expiry date?
No. Always check the expiry date on your KwikPen before use. Expired pens should be disposed of safely at a pharmacy. Using expired medication may be unsafe or ineffective.
What should I do if my Mounjaro pen is frozen?
Do not use a frozen pen. If your Mounjaro has been frozen, it may be damaged and unsafe to inject. Mounjaro should be stored at 2–8°C in the refrigerator but must never be frozen. Dispose of it and request a replacement from your pharmacy.
Is Mounjaro injection technique the same as Wegovy?
Both Mounjaro (tirzepatide) and Wegovy (semaglutide) use similar once-weekly injection pens and comparable injection techniques. However, Wegovy uses a different device (the Ozempic-style pen) rather than the KwikPen. Always follow the specific instructions for whichever medication you've been prescribed by your GP or prescriber.
Ready to take control of your weight loss journey?
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