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
Free Mounjaro Weight Loss Tracker for UK Adults
If you're considering or already taking Mounjaro for weight management, tracking your progress is essential to understand how the medication is working for you. MyWeightCheck offers free tools to help you monitor your weight loss journey alongside your prescription. Mounjaro (tirzepatide) is a once-weekly injectable medication that works as a dual GIP and GLP-1 receptor agonist, and individual results vary significantly. This guide explains how to track your progress effectively and what to expect during your treatment.
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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 to Track Mounjaro Weight Loss Effectively
Tracking your weight loss on Mounjaro requires consistency and realistic expectations. Weigh yourself at the same time each day or weekly — morning, after using the bathroom, before eating — for the most accurate readings. Record your weight in both kg and stone so you can see progress in the units you're most familiar with. Use our free BMI calculator alongside your weight tracking to see how your BMI category changes over time, and our weight converter if you need to switch between metric and imperial measurements.
Most people on Mounjaro experience gradual weight loss as they progress through dose titration. Doses increase every 4 weeks from 2.5mg up to a maximum of 15mg. Clinical trials showed an average weight loss of 15–21% of body weight, but your individual results depend on adherence, diet, and physical activity. Don't compare your progress to others — what matters is your own health improvements and whether the medication is helping you feel fuller for longer and reducing food cravings.
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.
Using MyWeightCheck's Free Weight Loss Calculator
Our free GLP-1 weight loss calculator helps you estimate potential weight loss at different Mounjaro doses based on clinical trial data. Enter your current weight and height, and the calculator projects approximate weight loss ranges at doses like 5mg, 10mg, and 15mg. This gives you a realistic picture of what to expect — though remember, individual results vary and these are average projections, not assures.
Beyond the numbers, track non-scale victories: improved energy levels, better appetite control, clothes fitting differently, improved blood sugar readings (if you have prediabetes), or reduced joint pain from carrying less weight. These changes often appear before significant scale weight loss and are valuable indicators that Mounjaro is working for you. If you're not seeing progress after 12 weeks on your target dose, discuss this with your prescriber — they may adjust your approach.
- 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 often should I weigh myself on Mounjaro?
Weighing once per week at the same time of day is ideal. Daily weighing can be misleading due to natural water weight fluctuations. Record weekly weights in our free progress tracker to see your trend over time. Avoid obsessive daily weigh-ins — focus on the bigger picture over 4–8 weeks.
What's the typical weight loss timeline on Mounjaro?
Most people see initial weight loss within the first 4 weeks, but more significant loss typically occurs as doses increase from 5mg to 10mg to 15mg. The dose titration phase lasts around 16–20 weeks. Clinical trials showed average weight loss of 15–21% over 72 weeks alongside diet and exercise changes.
Should I track other health markers besides weight?
Yes. Track blood pressure, waist circumference, blood sugar levels (if relevant), and how you feel — energy, appetite, mood. These health markers often improve before major weight loss. Use our free BMI calculator monthly to see your BMI category shift. Discuss all changes with your GP.
What if I'm not losing weight on Mounjaro?
If weight loss stalls after 12 weeks on a stable dose, your prescriber may increase your dose (if not already at 15mg) or review your diet and activity levels. Weight loss plateaus are normal — your body may be adjusting. Ensure you're in a calorie deficit and discuss any concerns with your prescriber.
How do I know if Mounjaro is right for me for long-term tracking?
Mounjaro is prescription-only and requires a clinical assessment. You'll need a BMI of 30 or above, or 27 or above with weight-related health conditions. If prescribed, commit to tracking for at least 3–6 months to assess its effectiveness for your specific situation.
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.