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
Is It Normal To Feel Hungry On Mounjaro?
Yes, it's normal to feel hungry on Mounjaro, especially when you first start the medication or during dose increases. While Mounjaro (tirzepatide) is designed to help reduce appetite through its dual GIP and GLP-1 mechanism, individual responses vary significantly. Some people experience reduced hunger quickly, whilst others may take several weeks to notice appetite suppression. If hunger persists or increases unexpectedly, it's important to discuss this with your GP or prescriber to rule out other factors and ensure your dose is appropriate for your needs.
10,000+ calculations today · NHS-aligned thresholds · 100% free
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.
Why Hunger Varies On Mounjaro
Mounjaro works by activating two hormone pathways—GIP and GLP-1—that signal fullness to your brain and slow gastric emptying. However, appetite suppression is not immediate or assured. Several factors affect how quickly you feel appetite reduction:
- Dose escalation: Hunger suppression typically improves as your dose increases from the starting 2.5 mg through to the maintenance dose (usually 5–15 mg). Each dose increase takes 4 weeks minimum, so early weeks may feel less effective.
- Individual metabolism: Some bodies respond to tirzepatide more quickly than others. Genetics, insulin resistance, and baseline hunger hormones all play a role.
- Diet and habits: How you eat matters. Mounjaro works best alongside a reduced-calorie diet and structured eating patterns—skipping meals or eating processed foods may reduce its effectiveness.
- Other medications: Certain diabetes or thyroid medications can influence appetite independently of Mounjaro.
It's also worth noting that feeling some hunger is normal and healthy—Mounjaro is meant to reduce excessive hunger, not eliminate appetite entirely.
Clinically BackedWeight Loss
No appointments. No waiting rooms. Just care — from a UK-regulated online pharmacy.
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 Speak To Your GP
If hunger remains severe or increases unexpectedly, contact your GP or the prescriber who issued your Mounjaro prescription. This may indicate: your current dose isn't optimal for your body, an underlying medical issue (thyroid problems, diabetes complications), or that Mounjaro may not be the right medication for you at present. Your prescriber can review your dose, adjust your meal plan, or discuss alternative weight management approaches. Additionally, if you experience hunger alongside nausea, vomiting, or stomach pain, seek medical advice promptly—these could signal other issues. Use our GLP-1 weight loss calculator above to track how your appetite and weight progress over time, which can help you discuss patterns with your GP more effectively.
- 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.
How long does it take for Mounjaro to reduce hunger?
Appetite suppression often begins within the first 2–4 weeks, but many people notice the strongest effect after reaching maintenance dose (weeks 5–20+). Initial weeks may feel less effective. If no change after 8 weeks on a stable dose, discuss this with your prescriber.
Is it normal to feel hungry between dose increases?
Yes. As your body adjusts to each dose, appetite may temporarily increase before the next dose escalation. This is why the Mounjaro schedule includes 4-week intervals at each dose level—allowing your body to adapt fully before increasing.
What should I eat if I'm hungry on Mounjaro?
Focus on protein-rich, high-fibre foods: chicken, fish, eggs, Greek yoghurt, vegetables, and whole grains. These keep you fuller longer. Avoid highly processed foods and sugary snacks, which trigger hunger spikes and reduce Mounjaro's effectiveness.
Can I increase my Mounjaro dose faster to reduce hunger?
No. The dose escalation schedule (4 weeks per dose level) is designed to minimise side effects and allow your body to adapt safely. Faster increases increase nausea and other complications without improving hunger suppression faster.
Should I worry if I still feel hungry on a high Mounjaro dose?
Not necessarily. Some people on maximum dose (15 mg) still experience mild hunger, which is normal. However, if hunger is intense or affecting your weight loss progress, your GP can review whether tirzepatide is the right medication, discuss alternative approaches, or investigate underlying health factors like thyroid issues.
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.