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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Do You Get Hungry On Mounjaro vs Wegovy?
Both Mounjaro and Wegovy are prescription weight loss injections that work by reducing appetite, but they use different mechanisms. Mounjaro (tirzepatide) is a dual GIP and GLP-1 receptor agonist, while Wegovy (semaglutide) activates GLP-1 only. Most people experience reduced hunger on both medications, though individual responses vary. Clinical trial data and real-world experience show that appetite suppression is typically stronger in the first weeks, with some adaptation over time. Understanding how each medication affects hunger can help you and your prescriber decide which might be more suitable for you.
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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 Reduce Hunger — Clinical Evidence
Mounjaro works through a dual mechanism: by activating both GIP (glucose-dependent insulinotropic polypeptide) and GLP-1 receptors, it sends multiple signals to the brain that you are full. This dual action may result in stronger appetite suppression compared to single-mechanism GLP-1 agonists. In the SURMOUNT-1 clinical trial, participants on the 15mg dose of Mounjaro reported significant reductions in hunger and food cravings.
Wegovy works through GLP-1 only: it activates one pathway, which also reduces appetite and slows how quickly food leaves your stomach. The STEP-1 clinical trial showed strong appetite reduction, though the mechanism is single rather than dual. Both medications can lead to reduced interest in food, smaller portion sizes, and feeling fuller after less food. However, many users report that appetite suppression is most pronounced in the first 4–8 weeks, with some adaptation to the medication over time. This is normal and does not mean the medication is becoming ineffective for weight loss.
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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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Individual Hunger Response and Prescriber Assessment
Hunger suppression on both Mounjaro and Wegovy varies between individuals — some people experience complete loss of appetite interest, while others notice moderate reduction in hunger with occasional appetite return. Factors that influence this include starting dose, rate of dose titration, individual body chemistry, and whether you are following a structured diet alongside the injection. Your prescriber will monitor your response when you start treatment and can adjust your dose based on how well appetite is controlled. If hunger returns significantly or you experience insufficient appetite suppression, a dose increase may be appropriate. Try our GLP-1 weight loss calculator above to estimate potential outcomes at different doses — this can help inform your discussion with your prescriber about which medication and dose level might suit your needs.
- 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 I feel hungry on Mounjaro or Wegovy?
Most people experience reduced hunger and food cravings on both medications. The dual GIP/GLP-1 mechanism of Mounjaro may provide stronger appetite suppression than Wegovy's single GLP-1 pathway, though individual responses vary significantly. Some people report almost complete loss of appetite interest, while others experience moderate reduction.
Does hunger come back while taking Mounjaro or Wegovy?
Appetite suppression is typically strongest in the first 4–8 weeks. Some adaptation may occur over time, meaning hunger sensations may partially return. This is normal and does not mean the medication is failing — weight loss can continue as the medication affects other metabolic pathways beyond appetite alone.
What if I still feel hungry on my current dose?
Discuss this with your prescriber. If appetite suppression is insufficient, a dose increase may be recommended. Both Mounjaro and Wegovy have titration schedules (gradual dose increases) specifically because appetite response varies. Your prescriber can adjust your treatment based on your individual response.
Is stronger appetite suppression always better for weight loss?
Not necessarily. Some people lose weight effectively with moderate appetite reduction because the medication also improves metabolic function and reduces cravings for specific foods. Weight loss depends on maintaining a calorie deficit alongside lifestyle changes, not just hunger suppression alone.
How do I know whether Mounjaro or Wegovy is right for me?
Your GP or prescriber will assess your medical history, current medications, weight, BMI, and any weight-related health conditions. Both medications require a prescription and clinical assessment. Your prescriber will explain the differences in mechanism and help you choose based on your individual suitability and preferences.
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.