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
Free tracker included with every download this week
Why Am I Feeling Hungry On Mounjaro?
Feeling hungry whilst on Mounjaro can be frustrating, especially when appetite suppression is one of the main reasons you started the medication. Hunger on tirzepatide is not uncommon — it can happen for several reasons, including dose timing, individual variation, incomplete dose titration, or underlying factors that need addressing. This guide explains what's happening and when to speak to your GP or prescriber.
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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.
Why Mounjaro Might Not Be Suppressing Your Appetite
Mounjaro (tirzepatide) works as a dual GIP and GLP-1 receptor agonist, activating natural hunger-regulation pathways in your brain and digestive system. However, not everyone experiences appetite suppression equally. Common reasons for continued hunger include:
- Dose too low: You may still be in dose titration. Mounjaro starts at 2.5 mg and increases gradually (every 4 weeks) to 5 mg, 7.5 mg, 10 mg, 12.5 mg, and finally 15 mg. Appetite suppression often improves significantly at higher maintenance doses.
- Early in treatment: Some people experience reduced appetite initially, then it returns slightly as the body adjusts. This is normal and may stabilise at your next dose increase.
- Individual variation: Not all bodies respond identically to tirzepatide. Some people are naturally less sensitive to appetite-suppressing hormones.
- Eating patterns: If you're eating large meals quickly, hunger signals may overwhelm the medication's effects. Smaller, more frequent meals help Mounjaro work more effectively.
- Underlying health factors: Stress, poor sleep, diabetes, hormonal changes, or certain medications can increase hunger despite taking Mounjaro.
Use our GLP-1 weight loss calculator to understand where you are in your treatment journey and what to expect at your current dose.
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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.
Free Weight Loss Tools & Guides
Everything you need to understand your weight, explore medication options, and track your progress — completely free.
When to Contact Your GP or Prescriber
If you're feeling unexpectedly hungry on Mounjaro, contact your prescriber before your next scheduled dose increase — they may recommend staying at your current dose longer, adjusting your eating patterns, or investigating underlying causes. Seek urgent medical advice if hunger is accompanied by dizziness, shaking, confusion, or rapid heartbeat (signs of low blood sugar). Always inform your GP about all symptoms and any other medications you're taking, as some drugs can interact with tirzepatide's effects. Your prescriber can also clarify whether you've reached your optimal dose or if an adjustment is needed. Don't reduce your dose without guidance.
- 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.
Is hunger a side effect of Mounjaro?
Hunger is not listed as a common side effect — in fact, reduced appetite is the intended effect. However, it's not uncommon for some people to experience continued or returning hunger, especially at lower doses or early in treatment. This usually improves with dose increases or dietary adjustments.
Will my hunger improve if I increase my Mounjaro dose?
Often, yes. Clinical trials show appetite suppression increases significantly at higher doses (10 mg, 15 mg). However, dose increases happen gradually every 4 weeks, and your prescriber must approve any changes. Never self-adjust your Mounjaro KwikPen dose.
Can I do anything to reduce hunger whilst on Mounjaro?
Yes. Eat smaller, more frequent meals; stay hydrated; prioritise protein and fibre; avoid trigger foods; manage stress; and ensure adequate sleep. These strategies complement tirzepatide's effects and improve weight loss outcomes.
Is feeling hungry on Mounjaro a sign the medication isn't working?
Not necessarily. Mounjaro works through multiple pathways beyond appetite — it affects how your body uses fat and regulates blood sugar. Some people lose weight effectively even if appetite suppression is modest. Your prescriber can assess effectiveness through regular weigh-ins.
Should I stop Mounjaro if I'm still hungry?
No. Contact your GP or prescriber instead. They can review your dose, eating patterns, and overall progress. Stopping without medical guidance may affect your weight management plan. Your prescriber can help troubleshoot and optimise your treatment.
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.