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
What Are Mounjaro Half Dose Clicks?
Mounjaro half dose clicks refer to the injection mechanism on the KwikPen device, which delivers tirzepatide in precise increments. In the UK, some patients may adjust their Mounjaro dose by half-clicks on the dose selector dial, though standard NHS and private prescribing typically follows the established dose escalation schedule. Understanding how your KwikPen works and how to use the dose selector correctly is essential for safe medication administration. Always follow your prescriber's specific guidance for your individual treatment plan.
10,000+ calculations today · NHS-aligned thresholds · 100% free
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 Dosing Works in the UK
Mounjaro is delivered via a pre-filled KwikPen auto-injection device available through NHS specialist services and private prescribers in the UK. The standard dose escalation schedule starts at 2.5 mg once weekly and increases by 2.5 mg increments every four weeks, up to a maximum of 15 mg weekly. Each dose level is maintained for a minimum of four weeks before escalation to allow your body to adjust.
The KwikPen dose selector dial shows the dose in milligrams, and clicking the dial advances the dose setting. Half-clicks on some devices may allow finer dose adjustments, though standard UK prescribing typically uses full-dose increments (2.5 mg, 5 mg, 7.5 mg, 10 mg, 12.5 mg, 15 mg). Your prescriber will specify your exact dose, and you should never adjust beyond your prescribed amount. If you have questions about your specific dose or the mechanics of your pen, contact your prescriber or pharmacist immediately.
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.
Prescription and Safety Considerations
Mounjaro is prescription-only in the UK and requires a clinical assessment before dispensing. Whether accessed through NHS tier 3 weight management services or private online prescribing, your prescriber will determine the appropriate starting dose and escalation plan based on your individual health, BMI, and any weight-related conditions.
Never adjust your dose without explicit instruction from your prescriber. Using a half-click to reduce or increase your dose outside of medical guidance could affect safety and efficacy. Store your KwikPen correctly (refrigerated before first use, up to 30 days at room temperature after), rotate injection sites weekly, and report any injection concerns or unexpected side effects to your healthcare provider immediately.
- 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 "half dose click" mean on a Mounjaro KwikPen?
A half-click refers to a partial turn of the dose selector dial on some KwikPen devices. However, UK prescribers typically use standard full-dose increments (2.5 mg steps). Half-clicks should only be used if your prescriber explicitly instructs you to do so. Always follow your specific prescription guidance.
Can I adjust my Mounjaro dose using half-clicks myself?
No. You should never adjust your Mounjaro dose without direct instruction from your prescriber. Your dose is set based on a clinical assessment, and only your healthcare provider can authorise changes. Contact your GP or prescriber if you think you need a dose adjustment.
What is the standard Mounjaro dose schedule in the UK?
The standard UK schedule starts at 2.5 mg weekly, increasing by 2.5 mg every four weeks. Maximum doses are 15 mg weekly. Each dose is maintained for at least four weeks before escalation to allow your body to adjust properly.
How do I know if I'm using my Mounjaro KwikPen correctly?
Your pharmacist should provide written instructions when you receive your first KwikPen. The device clicks audibly when you advance the dose selector. If you're unsure about any step, contact your pharmacy or prescriber before injecting. Never guess about dose administration.
What should I do if I accidentally use the wrong dose on my Mounjaro pen?
If you've accidentally set the wrong dose, do not inject. Reset your pen to the correct dose using the dose selector dial, or contact your pharmacist for guidance. If you've already injected an incorrect dose, contact your prescriber or NHS 111 for advice immediately.
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.