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 Meal Plans vs Wegovy: How Do They Compare?
If you're considering prescription weight loss treatment in the UK, understanding how Mounjaro and Wegovy differ in their effects on appetite and meal planning can help inform your decision. Both are prescription-only once-weekly injections that may help support weight loss through different mechanisms. While meal plans themselves aren't medication-specific, the way your body responds to food may differ between these two treatments. This guide explains the key differences and helps you understand what a prescriber will assess when determining which might be suitable for you.
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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.
Mounjaro vs Wegovy: Mechanism and Appetite Effects
Mounjaro (tirzepatide) is a dual GIP and GLP-1 receptor agonist, meaning it activates two natural hormone pathways simultaneously. This dual mechanism may help reduce appetite more intensely and support feeling fuller after smaller portions. Wegovy (semaglutide) is a GLP-1 receptor agonist only, activating a single pathway. In clinical trials, Mounjaro showed average weight loss of approximately 15–21% of body weight over 72 weeks, while Wegovy showed average weight loss of around 15% over 68 weeks at its maximum dose — though individual results vary significantly.
- Mounjaro: dual mechanism may produce stronger appetite suppression in some users
- Wegovy: single mechanism, well-established GLP-1 effects across clinical trials
- Both slow gastric emptying, making meals feel more satisfying
- Both require reduced-calorie diet and increased physical activity for best results
- Neither medication removes the need for dietary changes — they support, not replace, lifestyle adjustments
When considering which medication might suit you, your prescriber will assess your health history, previous weight loss attempts, and individual risk factors. Use our free GLP-1 weight loss calculator above to explore potential weight loss scenarios at different dose levels for both medications.
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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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Meal Planning Considerations: Which Might Suit You?
Both Mounjaro and Wegovy may alter how you experience hunger and fullness, meaning meal planning approaches often shift naturally during treatment. Many people find they eat smaller, more frequent meals or naturally prefer protein-rich foods. Neither medication is inherently "better" for meal planning — the right choice depends on your individual response, medical history, and what your prescriber assesses as most appropriate for you.
- Prescriber assessment is essential: eligibility isn't based on meal plan preferences
- UK BMI thresholds for prescription weight loss treatment are 30+ (or 27+ with weight-related health conditions)
- South Asian, Chinese, Black African, and Black Caribbean adults may have lower BMI thresholds due to higher cardiovascular risk
- A prescriber will discuss which medication aligns with your overall health profile
Check your current BMI using our free BMI calculator above to understand where you stand relative to NHS guidelines. Both medications are available through NHS specialist weight management services or private prescribing via online assessment.
- 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.
Do I need a special meal plan if I take Mounjaro or Wegovy?
No special meal plan is mandatory, but most people find their appetite naturally reduces and portion sizes decrease. Your GP or prescriber can offer dietary guidance. A balanced, reduced-calorie diet alongside the medication typically supports the best results. Some people find keeping a food diary helpful.
Which is better for meal planning — Mounjaro or Wegovy?
Neither is inherently "better" for meal planning. Both support smaller portions and reduced appetite. The choice depends on your individual health profile, medical history, and what your prescriber assesses as most suitable. Both require you to maintain a healthy diet and increased physical activity.
How does Mounjaro's dual mechanism affect eating habits differently than Wegovy?
Mounjaro's dual GIP and GLP-1 action may produce stronger appetite suppression in some people, potentially leading to smaller portions or less frequent eating. Wegovy's single GLP-1 mechanism is also effective but may feel slightly different individually. Results and experiences vary significantly between people.
Can I eat normally on Mounjaro or Wegovy?
You can eat normally, but most people naturally eat less and feel fuller faster. This is the medication's intended effect. You should still aim for balanced meals with adequate protein, vegetables, and whole grains. Very restrictive eating is not recommended — sustainable dietary changes work best.
How do I know if Mounjaro or Wegovy is right for me?
A UK-licensed prescriber will assess your medical history, current health conditions, BMI, and previous weight loss attempts. Both are prescription-only and require clinical assessment. Your GP can refer you to NHS specialist services, or you can access private online prescribing consultations. Individual suitability varies.
Ready to take control of your weight loss journey?
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