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 2.5mg Mounjaro?
The 2.5mg starting dose of Mounjaro comes as a single pre-filled KwikPen injection — you don't count individual clicks. Each KwikPen is pre-loaded with exactly one dose, so you simply inject the entire pen contents once weekly. This is different from older injection devices that required counting clicks. The Mounjaro KwikPen is designed for ease of use, with a straightforward injection process that takes just a few seconds.
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Calculate Your BMI Instantly
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.
Understanding Mounjaro KwikPen Dosing
Each Mounjaro KwikPen contains one complete weekly dose — whether that's 2.5mg, 5mg, 7.5mg, 10mg, 12.5mg, or 15mg. You don't need to count clicks or measure doses yourself. The pen is pre-filled and pre-dosed by the manufacturer, so you simply:
- Remove the pen from the fridge 15 minutes before use to allow it to reach room temperature
- Check the dose window to confirm the dose strength (printed on the pen label)
- Select your injection site — stomach, thigh, or upper arm
- Inject the entire pen contents once weekly
- Dispose of the pen safely in a sharps bin after use
The 2.5mg dose is typically the starting dose, used for the first 4 weeks. After 4 weeks, your prescriber will guide you to increase to the next dose level, usually 5mg, depending on your response and tolerance.
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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 Titration Schedule
Mounjaro uses a structured dose escalation schedule — your prescriber will not advise you to skip doses or adjust individual injections. Each KwikPen contains 4 weekly doses, so one pen lasts exactly one month. The typical titration follows: 2.5mg weeks 1–4, then 5mg weeks 5–8, continuing to increase every 4 weeks if appropriate, up to a maximum of 15mg weekly.
Your prescriber will assess your progress, side effects, and weight loss at each stage before recommending an increase. This gradual approach helps your body adjust and minimises gastrointestinal side effects. Never attempt to adjust doses yourself — always follow your prescriber's guidance. Our GLP-1 weight loss calculator can help you estimate projected outcomes at different doses alongside a reduced-calorie diet and increased physical activity.
- 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 Mounjaro the same as Ozempic?
Both contain the same medication (tirzepatide for Mounjaro, semaglutide for Ozempic), but they are different drugs. Mounjaro is licensed in the UK for weight management. Ozempic is approved for type 2 diabetes only and is not licensed for weight loss. Using Ozempic for weight loss is off-label in the UK.
How do I inject Mounjaro if there are no clicks?
The KwikPen is pre-dosed — simply hold the pen against your skin at 90 degrees and press the injection button. You'll hear a click sound as the needle deploys. The entire injection takes a few seconds. Full step-by-step guidance is provided in your patient information leaflet.
What if I miss a Mounjaro injection?
If you remember within 4 days of your missed dose, inject as soon as possible and continue your normal weekly schedule. If more than 4 days have passed, skip the missed dose and take your next injection on the scheduled day. Never inject twice in one week.
Can I adjust my Mounjaro dose myself?
No. Mounjaro dosing is managed by your prescriber only. Each KwikPen is pre-loaded with a specific dose. Dose changes are made by switching to a different pen strength, always under medical guidance, with a minimum of 4 weeks between increases.
How much does a single Mounjaro KwikPen cost on the NHS?
NHS access to Mounjaro for weight management is through specialist tier 3 weight management services, not standard GP prescription. Availability and cost vary by region. Private prescribing costs typically range from £129–£320 per month depending on dose strength.
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.