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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Why You Might Feel Hungry on Mounjaro vs Wegovy
Feeling hungry while taking Mounjaro is not uncommon, and it may happen for different reasons than with other weight loss injections like Wegovy. Although Mounjaro is a dual GIP and GLP-1 receptor agonist designed to suppress appetite, individual responses vary significantly. Some people experience strong appetite reduction, while others feel persistent hunger throughout their treatment. Understanding why this happens, how Mounjaro compares to Wegovy, and what you can do about it is essential for managing your weight loss journey effectively. This guide explains the differences in mechanism between these two prescription-only medications and what the clinical evidence shows.
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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.
Mounjaro vs Wegovy: Mechanism and Hunger Differences
Mounjaro (tirzepatide) and Wegovy (semaglutide) work differently in your body, which affects how hungry you feel. Mounjaro is a dual GIP and GLP-1 receptor agonist — it activates two separate hormone pathways, whereas Wegovy is a GLP-1 agonist only. In clinical trials, the SURMOUNT-1 study showed Mounjaro users lost an average of 15–21% of their body weight, while the STEP-1 trial showed Wegovy users lost approximately 15% on average. Both medications slow gastric emptying (how quickly food leaves your stomach), which reduces hunger, but Mounjaro's dual mechanism may theoretically provide stronger appetite suppression for some people.
However, individual responses vary considerably. Some people report less hunger on Wegovy, whilst others experience stronger suppression on Mounjaro. This depends on your personal metabolism, genetics, dose level, and how your body responds to each hormone pathway. Feeling hungry on Mounjaro does not mean the medication is not working — weight loss can continue even when appetite suppression feels inconsistent. Your prescriber may adjust your Mounjaro dose titration schedule or consider switching medications if hunger remains problematic.
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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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Managing Hunger and Choosing the Right Medication
If you are feeling hungry on Mounjaro, there are practical steps you can take. First, ensure you are on an adequate dose — appetite suppression often improves as you increase from the starting dose of 2.5 mg towards maintenance doses (10 mg to 15 mg). Eating high-protein, high-fibre meals helps you feel fuller longer, as does drinking plenty of water. Take your time eating and avoid trigger foods that stimulate cravings. Use our free GLP-1 weight loss calculator to track your progress — weight loss can continue even if hunger fluctuates.
Regarding choosing between Mounjaro and Wegovy: both are prescription-only and require a clinical assessment from a UK-licensed prescriber. Your GP or private prescriber will consider your medical history, previous treatment responses, and suitability for each medication. Neither is assured to work perfectly for every person, and switching between them is an option if hunger management becomes difficult. Always discuss persistent hunger or concerns with your prescriber rather than adjusting doses independently.
- 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.
Why do I feel hungry on Mounjaro when it's supposed to suppress appetite?
Mounjaro does suppress appetite, but individual responses vary significantly. Some people experience consistent hunger reduction whilst others feel variable appetite throughout the day. Hunger may improve as your dose increases during titration. It can also indicate you need a higher maintenance dose, or that your body responds differently to Mounjaro than expected. Always discuss persistent hunger with your prescriber.
Does Wegovy suppress hunger better than Mounjaro?
The clinical trial data shows both medications produce similar average weight loss (around 15% of body weight), suggesting comparable appetite suppression overall. However, individual experiences differ — some people report stronger hunger reduction on Wegovy, whilst others experience this more on Mounjaro. A UK-licensed prescriber can help determine which medication might suit your body better based on your medical history.
What should I do if I am feeling hungry on Mounjaro?
First, check your dose — appetite suppression often improves as you progress through dose titration towards your maintenance dose. Eat high-protein, high-fibre foods and drink plenty of water. Avoid trigger foods and eat slowly. If hunger persists at therapeutic doses, inform your prescriber — they may increase your dose further, discuss switching to Wegovy, or explore other management strategies. Do not adjust your dose independently.
Can I switch from Mounjaro to Wegovy if I feel too hungry?
Yes, switching is possible, but it must be managed by your UK-licensed prescriber. There is no official established conversion chart, though Mounjaro 15 mg is approximately equivalent to Wegovy 2.4 mg based on clinical practice. Your prescriber will assess whether switching is appropriate for you and manage the transition safely, including any washout period between medications.
Is feeling hungry on Mounjaro a sign it is not working?
No. Weight loss can continue even if appetite suppression feels inconsistent or weaker than expected. Hunger varies day-to-day and may improve over time. Check your progress using our free progress tracker or by monitoring your weight loss over weeks rather than days. Consistent weight loss over 4–12 weeks indicates the medication is working, even if hunger levels fluctuate.
Ready to take control of your weight loss journey?
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