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 Pen Clicks Chart — Understanding Your Doses
If you've been prescribed Mounjaro (tirzepatide) in the UK, understanding how to use your KwikPen correctly is essential. This guide explains how many pen clicks correspond to each dose, how the titration schedule works, and what you need to know about using your Mounjaro pen. Mounjaro comes as a pre-filled KwikPen device with four weekly doses per pen, and knowing exactly when to increase your dose is important for both effectiveness and safety.
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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.
How Mounjaro Doses and Pen Clicks Work
Mounjaro is supplied in the UK as a pre-filled KwikPen device containing four weekly injections. Each pen delivers a single dose once weekly. The KwikPen has a dose selector dial that you turn to set your required dose — this is not about counting "clicks" in the traditional sense, but rather turning the dial until it aligns with your prescribed dose number.
The standard Mounjaro dose titration schedule is:
- Weeks 1–4: 2.5 mg once weekly (starting dose)
- Weeks 5–8: 5 mg once weekly (first increase)
- Weeks 9–12: 7.5 mg once weekly
- Weeks 13–16: 10 mg once weekly
- Weeks 17–20: 12.5 mg once weekly
- Week 21+: 15 mg once weekly (maximum dose)
You must spend at least 4 weeks on each dose before increasing, unless your prescriber advises otherwise. Your KwikPen dial clearly shows each dose number, making it straightforward to select the correct dose for your week of treatment.
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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.
NHS Access, Eligibility, and Prescriber Guidance
In the UK, Mounjaro is available through NHS specialist weight management services (tier 3 services) for adults meeting NICE-approved eligibility criteria. You must have a BMI of 30 or above, or BMI of 27–29.9 with weight-related health conditions such as type 2 diabetes, high blood pressure, or cardiovascular disease. For South Asian, Chinese, Black African, or Black Caribbean adults, lower thresholds apply.
Access via NHS typically involves referral from your GP to a tier 3 specialist service, which assesses your suitability and manages your titration schedule. Private routes are also available through online clinical assessment. Your prescriber will provide specific guidance on your individual dose schedule. Use our free GLP-1 weight loss calculator to understand potential weight loss outcomes at different doses, and the BMI calculator to track your health metrics throughout 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.
How do I know which dose to inject from my Mounjaro KwikPen?
Your KwikPen has a dial with numbered dose settings. Turn the dial until the number aligns with your prescribed dose (2.5 mg, 5 mg, 7.5 mg, 10 mg, 12.5 mg, or 15 mg). Your prescriber will tell you which dose to use each week. The pen automatically prevents over-injection.
Can I stay on a lower Mounjaro dose if it's working for me?
Yes. You do not have to reach the maximum 15 mg dose. Your prescriber may recommend staying on a lower dose (such as 5 mg or 10 mg) if it is working well for you and you are tolerating it. The goal is effective weight management, not necessarily maximum dose.
What happens if I miss a Mounjaro injection?
If you miss your weekly injection, take it within 4 days of the missed date and continue your normal schedule. If more than 4 days have passed, skip that dose and inject on your normal weekly day. Never double-dose. Contact your prescriber if you are unsure.
Is Mounjaro available on the NHS in my area?
NHS access to Mounjaro varies by region. Your GP can refer you to your local tier 3 specialist weight management service, though waiting times differ significantly across the UK. Private prescription routes are available without NHS referral and may have shorter access times.
What is the difference between Mounjaro and Wegovy pens?
Mounjaro (tirzepatide) is a dual GIP and GLP-1 agonist with doses up to 15 mg weekly. Wegovy (semaglutide) is a single GLP-1 agonist with maximum dose of 2.4 mg weekly. Both are prescription-only and require clinical assessment. Clinical trials show Mounjaro may produce slightly larger average weight loss, but individual results vary significantly.
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.