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 Lunch Ideas — How Appetite Changes Differ From Wegovy
When taking Mounjaro or Wegovy, lunch becomes quite different — appetite naturally decreases, portion sizes reduce, and food satisfaction changes. Both medications work through GLP-1 pathways but with one key difference: Mounjaro is a dual GIP and GLP-1 receptor agonist, whilst Wegovy activates GLP-1 alone. Understanding how each medication affects your appetite and eating patterns can help you plan realistic, sustainable lunch choices. This guide compares the two approaches based on UK clinical trial data and prescriber guidance.
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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 Differ in Appetite Suppression
Mounjaro (tirzepatide) is a dual GIP and GLP-1 receptor agonist, meaning it activates two natural hormone pathways that regulate hunger and fullness. In the SURMOUNT-1 clinical trial, participants on the maximum Mounjaro dose (15 mg once weekly) lost an average of approximately 20.9% of their body weight over 72 weeks alongside a reduced-calorie diet and increased physical activity. Wegovy (semaglutide) is a GLP-1-only agonist; the STEP-1 trial showed an average weight loss of approximately 14.9% at the maximum 2.4 mg weekly dose under similar conditions. The dual mechanism of Mounjaro may provide slightly greater appetite suppression for some people, though individual results vary considerably. Both require a Mounjaro KwikPen or Wegovy pen respectively, and both require dose titration over 16–20 weeks before reaching maintenance.
- Mounjaro: dual GIP + GLP-1 activation, up to 15 mg weekly maximum dose
- Wegovy: GLP-1 activation only, up to 2.4 mg weekly maximum dose
- Trial data shows Mounjaro average weight loss ~15–21%, Wegovy ~14.9%
- Both slow gastric emptying — food stays in stomach longer, increasing satiety
- Both may reduce food cravings and increase feelings of fullness after smaller meals
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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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Choosing Between Mounjaro and Wegovy — Individual Suitability
Neither Mounjaro nor Wegovy is inherently "better" — suitability depends entirely on individual health factors, prescriber assessment, and how your body responds. Your GP or licensed prescriber will assess your medical history, current medications, Mounjaro eligibility under NHS NICE guidance, and personal preferences before recommending either medication. Some people respond better to dual GIP+GLP-1 activation; others do equally well on GLP-1 alone. Both medications are prescription-only and require clinical assessment before prescription. Both work most effectively when combined with a reduced-calorie diet, increased physical activity, and sustainable lifestyle changes. Track your progress and food intake using our free progress tracker to understand how either medication affects your specific appetite and eating patterns.
- Prescriber choice depends on medical assessment, not personal preference alone
- Individual response varies — no assures either will suit you better
- Both require prescription and ongoing clinical review
- Both most effective with diet, exercise, and behaviour change
- 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.
Will lunch be smaller on both Mounjaro and Wegovy?
Yes, both medications typically reduce appetite and portion sizes. You'll likely feel fuller after eating less. However, the degree of appetite suppression varies between individuals and may change as your body adjusts to each dose. Some people find lunch portions reduce significantly; others experience modest changes. Your prescriber will monitor how you respond.
What's the main difference between Mounjaro and Wegovy mechanisms?
Mounjaro is a dual GIP and GLP-1 receptor agonist — it activates two hormone pathways. Wegovy activates GLP-1 only. This difference may result in different appetite suppression levels, though clinical trial data shows both support meaningful weight loss. The SURMOUNT trial (Mounjaro) showed ~20.9% average weight loss; STEP-1 (Wegovy) showed ~14.9%.
Can I choose between Mounjaro and Wegovy myself?
No — both are prescription-only medications requiring clinical assessment. Your GP or licensed prescriber will assess your medical history, eligibility, current medications, and health factors to recommend which is appropriate for you. Suitability depends on individual circumstances, not personal preference alone.
Will appetite suppression be permanent on either medication?
Appetite reduction typically continues whilst taking the medication at therapeutic dose. However, some people experience tolerance to appetite suppression over time. If this occurs, your prescriber may adjust your dose or medication strategy. Appetite often increases again if you stop taking the medication, which is why lifestyle changes are essential.
How quickly will lunch portions reduce on Mounjaro vs Wegovy?
Both medications work gradually through dose titration over 16–20 weeks. Appetite reduction usually becomes noticeable around weeks 4–8, though timing varies. You may not feel dramatic changes immediately; they typically build as your dose increases. Use our GLP-1 weight loss calculator to estimate timelines based on your starting weight and projected results.
Ready to take control of your weight loss journey?
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