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 Still Feeling Hungry on Mounjaro?
Feeling hungry despite taking Mounjaro is more common than you might think. While clinical trials show this tirzepatide injection works well for most people, appetite suppression varies significantly between individuals. Some people experience strong appetite control from the start, whilst others find their hunger returns or never fully diminishes. If you're struggling with persistent hunger on Mounjaro, there are several reasons why this might be happening and practical steps you can take. This guide covers what you need to know in a UK context, including 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.
Common Reasons Why Hunger Persists on Mounjaro
Individual variation in response: Mounjaro's dual GIP and GLP-1 mechanism works differently in different bodies. Some people have naturally higher baseline hunger signals or different sensitivity to appetite-suppressing hormones. This is completely normal and doesn't mean the medication isn't working for you overall.
You may need a higher dose: Mounjaro starts at 2.5 mg and escalates gradually to a maximum of 15 mg. If you're still feeling hungry, you might benefit from dose titration — moving to the next dose level. Your prescriber will only escalate after minimum 4 weeks at your current dose. Clinical trials showed stronger appetite suppression at higher doses, particularly at 10 mg and 15 mg.
Eating patterns matter: Even with appetite suppression, if you're eating frequently or consuming very palatable foods (high sugar, high fat), hunger signals can return. Mounjaro reduces appetite but doesn't eliminate the desire to eat — structured meal timing and food choices still matter.
Underlying conditions: Stress, poor sleep, certain medications, or hormonal changes can increase hunger independent of Mounjaro. These factors can work against the medication's effects.
Not enough time has passed: Some people report that appetite suppression improves over weeks 8–12 of treatment as their body adjusts. If you're very early in treatment, this may improve naturally.
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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.
What You Should Do — NHS and Private Routes
If you're persistently hungry on Mounjaro, contact your GP or the prescriber who issued your prescription — don't simply increase your dose yourself. Your prescriber can review your current dose, how long you've been on it, and whether escalation is appropriate. Through NHS tier 3 specialist weight management services, your team may recommend staying at your current dose longer, moving to the next dose level, or reviewing your diet and activity patterns. Privately prescribed Mounjaro includes prescriber support — use this to discuss your concerns. Some people find switching to an alternative GLP-1 medication like a semaglutide-based option (Wegovy) helps, though this requires a new clinical assessment. Use our GLP-1 weight loss calculator to explore potential outcomes at different doses, and track your progress even if hunger remains — you may still be losing weight effectively despite feeling hungry.
- 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.
Does feeling hungry mean Mounjaro isn't working?
No. Mounjaro can still be effective at supporting weight loss even if you're feeling hungry. Appetite suppression is just one mechanism — the medication also affects how your body processes food and stores fat. Some people lose weight steadily whilst experiencing more hunger than others. Discuss this with your prescriber, as dose adjustment may help.
Should I request a dose increase if I'm still hungry?
Don't self-increase your dose. Contact your GP or prescriber first. They'll assess how long you've been on your current dose, whether you've given it enough time to work, and if you're a suitable candidate for escalation. Dose increases typically happen every 4 weeks minimum, stepping from 2.5 mg up to 15 mg maximum.
Could another medication like Wegovy work better if I'm hungry on Mounjaro?
Possibly, but this requires a new clinical assessment. Wegovy (semaglutide) is a single GLP-1 agonist, whilst Mounjaro is a dual GIP and GLP-1 agonist. Some people respond better to one than the other, but evidence suggests similar overall weight loss. Your prescriber can advise if a switch is appropriate for you.
How long should I wait before deciding Mounjaro isn't suppressing my appetite?
Give it at least 8–12 weeks at your target dose before concluding it isn't working. Appetite suppression sometimes improves over this period as your body adjusts. If you're escalating doses, restart this timeline at each new dose. Speak to your GP if you're concerned before 12 weeks.
Can I use diet and exercise strategies alongside Mounjaro to manage hunger?
Yes — absolutely. Mounjaro works best combined with a reduced-calorie diet and increased physical activity. Structured meal timing, adequate protein intake, staying hydrated, and regular movement all support weight loss and can help manage hunger signals. Your prescriber or a dietitian can offer specific guidance.
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.