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
Should I Feel Hungry On Mounjaro?
When you start Mounjaro (tirzepatide), you'll typically experience reduced hunger and appetite — this is how the medication works. However, some people report still feeling hungry, especially at lower doses or as their body adjusts. How much hunger you feel varies significantly between individuals. If you're concerned about persistent hunger while taking Mounjaro, it's important to discuss this with your prescriber, as it may indicate you need a dose adjustment or that this medication isn't the best fit for you personally.
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Calculate Your BMI Instantly
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 Affects Hunger and Appetite
Mounjaro is a dual GIP and GLP-1 receptor agonist — it activates two natural hormone pathways that regulate appetite and satiety. When you take Mounjaro, it signals to your brain that you're full, typically reducing hunger and food cravings. The medication also slows how quickly food leaves your stomach, which helps you feel fuller for longer after meals.
At lower doses (2.5 mg to 5 mg), appetite suppression may be modest, and some people still feel hungry between meals or at certain times of day. As you progress through dose titration — moving through 7.5 mg, 10 mg, 12.5 mg, and up to the maximum 15 mg — hunger suppression typically increases. However, this doesn't happen for everyone at the same rate. Some individuals experience strong appetite reduction immediately, whilst others take several weeks to notice changes. Your own experience depends on your metabolism, how your body responds to GLP-1 signalling, and other individual factors. Using our GLP-1 weight loss calculator can help you understand what realistic expectations might be for your weight loss journey on Mounjaro.
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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.
Why You Might Still Feel Hungry on Mounjaro
If you're still experiencing hunger on Mounjaro, several factors could explain this:
- Dose is too low: Lower doses provide less appetite suppression. You may need to progress to a higher maintenance dose.
- Early adjustment period: Your body may need 2–4 weeks to fully respond to each dose before benefits peak.
- Individual variation: GLP-1 sensitivity varies — some people are more responsive than others to the medication's appetite-suppressing effects.
- Eating patterns: Mounjaro reduces hunger but doesn't prevent you from eating if you choose to. Portion control and food choices still matter.
- Other medications: Some medications can interfere with appetite suppression or increase hunger signals.
Your prescriber should be notified if hunger remains problematic, as they can consider dose adjustments or discuss whether Mounjaro is the right choice for you.
- 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 it normal to still feel hungry on Mounjaro?
Yes, it's normal, especially at lower doses or during the first few weeks on each dose. Appetite suppression typically increases as you progress through dose titration. However, if hunger remains severe after several weeks at a stable dose, contact your prescriber — you may need a higher dose or a different medication.
How long does it take for Mounjaro to reduce hunger?
Appetite suppression often begins within the first week, but can take 2–4 weeks to fully develop at each dose level. Most people notice significant hunger reduction by week 4–8 on Mounjaro. Individual timelines vary considerably.
Will Mounjaro completely stop hunger?
Mounjaro significantly reduces hunger and food cravings for most people, but complete elimination of hunger is not assured. Some people still experience moderate hunger, particularly between meals. Results vary based on dose, individual metabolism, and how responsive your body is to GLP-1 signalling.
Should I eat if I'm not hungry on Mounjaro?
You should still eat regular, balanced meals even if you're not hungry — skipping meals can lead to nutrient deficiency and muscle loss. Mounjaro reduces hunger but doesn't mean you can skip nutrition. Eat smaller portions when not hungry, but maintain adequate protein and micronutrients.
When should I tell my GP about hunger on Mounjaro?
Contact your prescriber if: hunger remains severe after 4+ weeks at a stable dose, you're struggling to eat enough to maintain health, or if hunger suddenly returns after initial suppression. They can assess whether you need dose adjustment, a different medication like Wegovy (semaglutide), or further investigation.
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.