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
Feeling Hungry on Mounjaro — What This Means for You
If you're taking Mounjaro and still feel hungry, you're not alone. Appetite suppression is one of tirzepatide's key mechanisms, but hunger can persist for several reasons — including insufficient dose escalation, individual variation in how your body responds, or eating patterns that haven't yet adapted. Understanding why this happens, and knowing your UK access and cost options, helps you make informed decisions about your weight management journey.
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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.
Understanding Hunger on Mounjaro — Dose, Timing, and Response
Mounjaro works by activating GIP and GLP-1 hormone pathways, which signal fullness to your brain and slow gastric emptying. However, hunger on Mounjaro can occur for several reasons:
- Early in treatment: At starting doses (2.5 mg), appetite suppression may be mild. Most people don't reach maximum appetite reduction until higher doses (10–15 mg).
- Individual variation: How your body responds to tirzepatide differs significantly — some people experience profound appetite reduction, others experience modest changes.
- Eating habits: If you're eating quickly, choosing high-calorie foods, or eating at specific trigger times, hunger signals may override the medication's effects.
- Dose timing: Mounjaro reaches peak levels 1–3 days after injection. Hunger may increase as levels drop toward day 7.
Try our GLP-1 weight loss calculator to estimate how tirzepatide dosing might affect your potential outcomes — individual responses vary widely.
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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.
Accessing Mounjaro in the UK — NHS vs Private Routes and Costs
NHS access: Mounjaro is approved by NICE for NHS specialist weight management services (tier 3). However, access is limited by regional availability and long waiting lists — some areas have minimal access. You'll need a GP referral to a specialist service.
Private access: UK-licensed online prescribers can issue Mounjaro prescriptions following an online clinical assessment. GPhC-registered pharmacies then dispense the medication. Costs typically range from £149–£320 per month depending on dose. The Mounjaro KwikPen (4 weeks' supply) is usually the standard format. Expect your first appointment to cost £40–£150, with ongoing prescriptions at similar prices or lower with repeat access.
Check your eligibility using our free BMI calculator, then consult a prescriber to discuss whether Mounjaro suits your health profile.
- 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.
Why am I still hungry if Mounjaro is supposed to reduce appetite?
Appetite suppression on Mounjaro varies greatly between individuals. If you're at a low dose (2.5–5 mg), hunger may be less pronounced than at higher doses. Some people also experience appetite return as their body adapts. Always discuss persistent hunger with your prescriber — a dose increase or adjustment may help.
Does hunger mean Mounjaro isn't working for me?
Not necessarily. Weight loss on tirzepatide happens through multiple mechanisms, including reduced calorie intake, slowed digestion, and improved fat utilisation. You can lose weight without complete appetite suppression. Your prescriber will assess your progress based on weight trends and health outcomes, not appetite alone.
How long does it take to feel appetite suppression on Mounjaro?
Most people notice appetite reduction within 1–2 weeks of starting Mounjaro 2.5 mg, though it's often subtle. Effects typically become more pronounced as you escalate doses every 4 weeks. Peak appetite suppression usually occurs at higher maintenance doses (10–15 mg). Individual timing varies.
Can I get Mounjaro on the NHS in the UK?
Yes — NICE has approved tirzepatide for NHS weight management services. However, NHS access is limited by regional availability and waiting lists can be very long (months to years in some areas). Most people access Mounjaro privately through online prescribing. Your GP can refer you to specialist tier 3 services if NHS access is available locally.
What's the difference between Mounjaro and Wegovy if I'm feeling hungry on Mounjaro?
Both Mounjaro (tirzepatide) and Wegovy (semaglutide) suppress appetite, but Mounjaro uses dual GIP and GLP-1 mechanisms versus Wegovy's single GLP-1 mechanism. If hunger persists on one, switching to the other (under prescriber guidance) might help — though individual responses are unpredictable and results vary considerably.
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.