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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Counting Clicks on Mounjaro vs Wegovy — A UK Comparison
Both Mounjaro and Wegovy are prescription-only weight management injections used in the UK, but they work differently and have different dose schedules. Understanding how many "clicks" or doses each requires, and how they compare in clinical trials, can help you and your GP make an informed decision. This guide explains the key differences between these two GLP-1 and dual-action medications, their dosing patterns, and what the evidence shows about their effectiveness.
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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 and Wegovy Dosing Differs
Mounjaro (tirzepatide) uses a dual GIP and GLP-1 receptor agonist mechanism, meaning it activates two separate hormone pathways to help reduce appetite and support weight management. The dosing starts at 2.5 mg once weekly and escalates every 4 weeks: 5 mg, 7.5 mg, 10 mg, 12.5 mg, and finally 15 mg as the maximum maintenance dose. Each KwikPen contains 4 weeks' worth of doses (4 clicks = 4 injections). Counting your Mounjaro clicks is straightforward — you inject the same dose once per week on your chosen day.
Wegovy (semaglutide) uses a single GLP-1 mechanism. Dosing is more gradual, starting at 0.25 mg and escalating through 0.5 mg, 1 mg, 1.7 mg, before reaching the maximum 2.4 mg dose. Like Mounjaro, Wegovy is a once-weekly injection. The slower titration schedule means it takes longer to reach the full maintenance dose — approximately 16–20 weeks compared to Mounjaro's typical 20 weeks.
- Mounjaro: 6 possible doses (2.5 mg to 15 mg)
- Wegovy: 5 possible doses (0.25 mg to 2.4 mg)
- Both: Once-weekly injections, easy to remember schedule
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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.
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Clinical Trial Results and Individual Suitability
In the SURMOUNT-1 clinical trial, Mounjaro at 15 mg achieved average weight loss of approximately 20.9% of body weight over 72 weeks. Wegovy, in the STEP-1 trial, achieved average weight loss of approximately 14.9% at its maximum 2.4 mg dose over 68 weeks. These figures are averages — individual results vary significantly based on diet, exercise, genetics, and other factors. Both medications work best when combined with a reduced-calorie diet and increased physical activity. Your GP or prescriber will assess which medication is clinically appropriate for you based on your health history, current medications, and weight management goals. Try our free GLP-1 weight loss calculator to see projected outcomes at different doses, and use our BMI calculator to understand your starting point.
- 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 many clicks does a Mounjaro KwikPen contain?
Each Mounjaro KwikPen contains 4 pre-filled doses — one injection per week for 4 weeks. You'll receive a new pen every month. Each pen delivers the same dose (e.g., all four clicks from a 10 mg pen will deliver 10 mg each).
Is Mounjaro better than Wegovy for weight loss?
Clinical trials show Mounjaro achieved slightly higher average weight loss (20.9%) than Wegovy (14.9%), but individual results vary significantly. "Better" depends on your personal health profile, other medications, and how your body responds. Your GP will assess suitability.
Why does Mounjaro have a dual mechanism and Wegovy only GLP-1?
Mounjaro (tirzepatide) activates both GIP and GLP-1 pathways, which may enhance appetite suppression. Wegovy (semaglutide) activates GLP-1 only. The dual action may explain Mounjaro's slightly higher average weight loss in trials, though both are effective.
Can I switch from Wegovy to Mounjaro or vice versa?
Switching between medications is possible but must be managed by your prescriber. There's no official conversion chart — your GP will assess the switch based on your response and any side effects. Do not switch without medical guidance.
How do I get prescribed Mounjaro or Wegovy in the UK?
Both medications are prescription-only and available through NHS specialist weight management services (with significant waiting lists) or private online prescribing following a clinical assessment. Your GP can refer you to NHS services, or you can access private prescribing through a registered UK provider.
Ready to take control of your weight loss journey?
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