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 For Half Dose Mounjaro?
The Mounjaro KwikPen does not have a "half dose" click setting — each numbered click delivers a complete, fixed dose. If you need to adjust your mounjaro dose, this is done by your prescriber through dose titration over weeks, not by taking partial clicks. Understanding how the KwikPen works and what each dose contains is essential for safe, effective use of this prescription-only tirzepatide injection in the UK.
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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 Mounjaro KwikPen Clicks Work
The Mounjaro KwikPen delivers one complete dose per click — there is no partial dosing option built into the device. Each numbered setting (2.5 mg, 5 mg, 7.5 mg, 10 mg, 12.5 mg, 15 mg) represents the full weekly injection for that dose level. The pen is designed this way to ensure dosing accuracy and safety.
- One click = one complete dose for that dose level
- The pen cannot be set to deliver half of a dose
- If dose reduction is needed, your prescriber will adjust to a lower complete dose
- Each KwikPen contains 4 weeks of doses (one injection per week)
- The pen has a safety mechanism that prevents accidental multiple clicks
If you have been prescribed a specific dose, you inject the entire amount that click represents. Attempting to partially depress the pen or use it in non-standard ways risks inaccurate dosing and is not recommended.
Clinically BackedWeight Loss
No appointments. No waiting rooms. Just care — from a UK-regulated online pharmacy.
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 Titration and UK Dosing Schedule
Mounjaro doses are adjusted in steps over weeks under medical supervision, not taken as partial injections. Your GP or prescriber will start you on 2.5 mg for weeks 1–4, then increase to the next full dose (5 mg, 7.5 mg, etc.) every 4 weeks based on your response and tolerance.
- Minimum 4 weeks between dose escalations
- Your prescriber assesses your progress at each stage
- Any dose adjustment requires a new prescription
- You never manually reduce or split a dose yourself
If you experience side effects or have concerns about your current dose, contact your prescriber immediately — do not attempt to halve or skip doses on your own. Using our free GLP-1 weight loss calculator can help you understand potential outcomes at your current prescribed dose as you progress through your treatment plan.
- 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.
Can I use the Mounjaro pen to inject only half a dose?
No. The KwikPen is designed to deliver complete doses only — each numbered setting injects the full prescribed amount. Attempting to partially press the pen risks inaccurate dosing. If you need a lower dose, your prescriber will prescribe the next lower complete dose level (e.g., switching from 5 mg to 2.5 mg).
What if I need to stop Mounjaro mid-way through a week?
You should not skip or stop doses without guidance from your prescriber. If you miss your weekly injection, take it within 4 days of the scheduled date and continue your normal weekly schedule. If more than 4 days have passed, skip that dose and resume the following week. Always contact your GP if you need to pause or stop treatment.
How do I know which number to dial on the Mounjaro KwikPen?
Your prescription will specify your dose (2.5 mg, 5 mg, 7.5 mg, 10 mg, 12.5 mg, or 15 mg). Match this dose to the number on the pen dial. The KwikPen displays the dose amount clearly — align the window with the prescribed dose number before injecting. Your prescriber or pharmacist will show you how to use it correctly.
What is tirzepatide and how is it different from semaglutide (Wegovy)?
Tirzepatide is the active ingredient in Mounjaro — it is a dual GIP and GLP-1 receptor agonist that works through two hormone pathways. Semaglutide (found in Wegovy) activates only the GLP-1 pathway. Clinical trials suggest tirzepatide may support slightly greater weight loss on average, though individual results vary significantly and both are prescription-only medicines.
Should I use the progress tracker to monitor my Mounjaro treatment?
Yes, tracking your weight weekly using our free progress tracker can help you monitor your response to treatment over your titration schedule. Recording your weight consistently allows you to see trends and share meaningful data with your prescriber at review appointments, supporting informed decisions about dose adjustments or continuing your treatment.
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.