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
Do You Still Get Hungry On Mounjaro?
Yes, most people on Mounjaro still experience some hunger, but it is typically significantly reduced compared to before starting treatment. Mounjaro (tirzepatide) is a dual GIP and GLP-1 receptor agonist that works by signalling to your brain that you are fuller, faster—but hunger is not completely eliminated. How much appetite reduction you experience varies between individuals and often depends on your dose, how long you have been taking the medication, and your personal body chemistry. Understanding what to realistically expect helps you use Mounjaro effectively alongside dietary changes and physical activity.
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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 Reduces Appetite
Mounjaro works differently from simple appetite suppressants. As a dual GIP and GLP-1 receptor agonist, it activates two natural hormone pathways that regulate hunger and fullness. The medication helps you feel satisfied after eating smaller portions, slows how quickly food leaves your stomach, and may reduce cravings for certain foods—particularly foods high in sugar and fat. However, this is not the same as eliminating hunger entirely. You will still recognise physical hunger signals, but they may feel less urgent or intense. The appetite-suppressing effect typically develops gradually as your body adjusts to each dose during the dose titration phase (increasing from 2.5 mg up to 15 mg over several weeks). Some people report the strongest appetite reduction in weeks 4–8 after starting, while others notice steady improvement over months. Individual variation is significant—factors like your baseline metabolism, eating habits, stress levels, and sleep quality all influence how pronounced the hunger reduction feels.
Clinically BackedWeight Loss
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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 to Expect: Hunger Patterns on Mounjaro
Early on Mounjaro, you may notice that eating a normal-sized meal leaves you uncomfortably full, or that you forget to eat because hunger signals are quieter. Some people describe feeling "satisfied with less" rather than completely appetite-free. As your body adapts to higher doses, appetite reduction may stabilise at a new baseline—not always increasing or decreasing further. Important context: hunger reduction alone does not clinically studied weight loss. You still need to make conscious food choices and maintain a calorie deficit. Our GLP-1 weight loss calculator can help you project realistic weight loss outcomes based on dose and lifestyle factors. If you find hunger returns strongly, this may indicate you need a dose increase, or it could signal that side effects (like nausea or constipation) are reducing, allowing appetite to return slightly. Always discuss appetite changes with your prescriber—they can adjust your dose or provide additional support.
- 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.
Will Mounjaro stop me feeling hungry completely?
No. Mounjaro significantly reduces appetite for most people, but hunger is not completely eliminated. You will still experience some hunger signals, though they are typically quieter and easier to manage. The goal is to help you feel satisfied with smaller portions, not to remove hunger entirely.
When does the hunger-suppressing effect start on Mounjaro?
Many people notice reduced appetite within the first 2–4 weeks of starting, but the effect can take longer for others. As you progress through dose titration (increasing the dose every 4 weeks from 2.5 mg to 15 mg), appetite reduction may become more pronounced. Full effects typically develop by weeks 8–12.
Can appetite return while on Mounjaro?
Yes. Some people find appetite increases slightly as their body adapts to a stable dose, or if side effects like nausea reduce. This is normal and does not mean the medication has stopped working. Your prescriber can discuss whether a dose increase is appropriate or if other adjustments would help.
Does reduced hunger on Mounjaro mean I do not need to diet?
No. Mounjaro is most effective when combined with a reduced-calorie diet and increased physical activity. The medication makes it easier to eat less by reducing cravings and increasing fullness, but you still need to make healthy food choices to achieve sustainable weight loss.
Is Mounjaro the same as Wegovy?
No. Both are prescription-only weight management injections, but Mounjaro (tirzepatide) is a dual GIP and GLP-1 agonist, while Wegovy (semaglutide) is a GLP-1 agonist only. Mounjaro may produce stronger appetite reduction for some people, but individual responses vary. Your prescriber can advise which is more suitable for you.
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.