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
Still Hungry on Mounjaro 2.5 — Is This Normal?
Feeling hungry while taking the starting dose of Mounjaro (tirzepatide) 2.5 mg is completely normal and expected. The 2.5 mg dose is an adjustment phase — it's designed to help your body adapt to the medication, not yet to deliver full appetite suppression. Most people experience noticeable appetite reduction only after reaching the 5 mg dose or higher. Understanding this progression helps you stay motivated and know what to expect as your tirzepatide dose titration continues over the coming weeks.
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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.
Why You May Still Feel Hungry at 2.5 mg
Mounjaro works by activating two hormone pathways: GIP and GLP-1 receptors. The starting 2.5 mg dose is deliberately low — it allows your body to adjust to the medication and minimises side effects like nausea. At this dose, the appetite-suppressing effects are mild because the receptor activation is still ramping up.
- Weeks 1–4: 2.5 mg is primarily a tolerance-building phase. Hunger suppression is subtle or barely noticeable.
- Weeks 5–8: Escalation to 5 mg — this is where most people first notice meaningful appetite reduction.
- Weeks 9+: Doses of 7.5 mg and higher typically produce stronger appetite suppression effects.
Clinical trial data shows that weight loss results are minimal at the 2.5 mg dose alone. The SURMOUNT-1 trial demonstrated that meaningful weight loss acceleration occurs at 5 mg and above. Feeling hungry at 2.5 mg is not a sign the medication isn't working for you — it's the expected physiological response at the starting 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.
What to Do If You're Still Hungry
Stay the course with your prescribed dose escalation schedule. Do not increase your dose early — Mounjaro requires a minimum of 4 weeks at each dose level before moving to the next. This ensures your body adapts safely. Continue following a reduced-calorie diet and increased physical activity even while appetite suppression is still developing. These lifestyle changes remain the foundation of weight loss, regardless of medication dose.
If you reach higher doses (10 mg, 15 mg) and still experience significant hunger, discuss this with your prescriber. They may review your diet, medical history, or medication response. Our free GLP-1 weight loss calculator can help you project expected outcomes at different doses — this may help contextualise your experience against clinical trial averages.
- 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 at 2.5 mg Mounjaro a sign it's not working?
No. The 2.5 mg starting dose is designed to help your body adjust to tirzepatide — appetite suppression is minimal at this phase. As your dose increases to 5 mg and higher over the coming weeks, you'll typically notice stronger appetite reduction. Hunger at the starting dose is expected and normal.
When will I notice appetite suppression on Mounjaro?
Most people report noticeable appetite reduction from week 5 onwards, once they've escalated to 5 mg. Full appetite suppression effects typically develop as doses progress to 7.5 mg, 10 mg, or higher. Individual responses vary — some feel effects sooner, others take longer.
Can I increase my Mounjaro dose faster to feel fuller?
No. Mounjaro requires a minimum of 4 weeks at each dose before escalating, regardless of hunger level. Faster escalation increases nausea and side effect risk without improving safety or outcomes. Your prescriber will manage dose titration — never adjust it yourself.
Should I diet differently while hungry on 2.5 mg Mounjaro?
Yes. The 2.5 mg dose does not eliminate hunger, so structured calorie reduction and increased physical activity remain essential. A reduced-calorie diet (not extreme restriction) alongside the medication gives the best results. Your GP or prescriber can advise on appropriate calorie targets for you.
What if I'm still very hungry at 10 mg or 15 mg Mounjaro?
Persistent hunger at higher doses is uncommon but does happen — individual responses vary significantly. Discuss this with your prescriber. They may review your diet quality, meal timing, or consider whether another medication approach suits you better. Some people benefit from additional dietary or behavioural support.
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.