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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How To Maximise Weight Loss On Mounjaro
Weight loss results with Mounjaro vary significantly between individuals, but there are evidence-based steps you can take to support better outcomes. Mounjaro (tirzepatide) is a prescription-only weekly injection that works alongside lifestyle changes — not instead of them. This guide covers practical strategies to help you get the most from your treatment, including dietary approaches, physical activity, dose progression, and monitoring. Always follow your prescriber's guidance, as individual circumstances differ.
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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.
Diet And Calorie Deficit: The Foundation Of Weight Loss
Mounjaro works best when combined with a reduced-calorie diet. Clinical trials showed that weight loss occurred when participants ate fewer calories alongside the medication — the injection supports appetite control, but you still need to create a calorie deficit. The NHS recommends aiming for a deficit of around 500 kcal per day, which typically results in approximately 0.5–1 kg weight loss per week. Consider these approaches:
- Protein intake: Aim for 1.2–1.6g per kg of body weight to preserve muscle during weight loss and support satiety
- Whole foods: Focus on vegetables, lean protein, whole grains, and minimally processed foods rather than calorie-dense ultra-processed options
- Meal structure: Smaller, balanced meals may suit you better on Mounjaro as your appetite is naturally reduced
- Hydration: Drink adequate water — dehydration can be mistaken for hunger and may worsen nausea
Use our free GLP-1 weight loss calculator to estimate potential outcomes at your current dose, then adjust your dietary approach based on your progress.
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.
Physical Activity, Dose Titration, And Consistent Monitoring
Exercise accelerates results. The SURMOUNT trials showed that participants who combined Mounjaro with increased physical activity achieved greater weight loss than diet alone. Aim for at least 150 minutes of moderate aerobic activity per week, plus 2–3 sessions of resistance training — this preserves muscle, boosts metabolism, and improves cardiovascular health. Dose progression matters: Mounjaro is titrated from 2.5 mg up to 15 mg over weeks. Staying on each dose for the recommended 4 weeks allows your body to adjust and maximises appetite suppression at that level before increasing. Don't rush escalation. Finally, track your progress consistently — weight fluctuates daily due to hydration and hormones, so weigh yourself weekly (same day, same time) and monitor trends over 2–4 weeks rather than daily changes. Our progress tracker helps you identify patterns and stay motivated.
- 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 much weight can I expect to lose on Mounjaro?
Clinical trials showed average weight loss of 15–21% of body weight over 72 weeks at doses of 5–15 mg, alongside diet and exercise. Individual results vary significantly — some people lose more, some less. Your prescriber can discuss realistic expectations based on your starting weight and health profile.
Does Mounjaro work without diet changes?
Mounjaro is most effective when combined with dietary changes and increased physical activity. The injection supports appetite control, but it's not a replacement for lifestyle changes. Weight loss in clinical trials occurred because participants ate less — Mounjaro made this easier, not automatic.
What dose of Mounjaro gives the best weight loss?
Maximum weight loss typically occurs at the 15 mg dose, but this is reached gradually through 4-week titration steps (2.5 mg → 5 mg → 7.5 mg → 10 mg → 12.5 mg → 15 mg). Your prescriber will recommend the appropriate dose for you based on your response and any side effects.
How long does it take to see weight loss results on Mounjaro?
Most people notice reduced appetite within 1–2 weeks of starting. Measurable weight loss typically appears within 4–8 weeks, though this varies. Consistency with diet and exercise during the first month is crucial before dose increases.
Should I stop eating foods I enjoy on Mounjaro?
No — you can eat the same foods, but smaller portions. Mounjaro reduces hunger and food cravings, making it easier to eat less naturally. Many people find they naturally prefer healthier options as cravings diminish, but restrictive dieting isn't necessary and may be unsustainable.
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.