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
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Starting to Feel Hungry on Mounjaro — What It Means for Your Treatment
If you're starting to feel hungry on Mounjaro (tirzepatide), it's a sign your body may be adjusting to the medication or your current dose. Appetite suppression is the primary way Mounjaro works, so returning hunger can mean you're ready to increase your dose, your medication needs reviewing, or you may benefit from switching approaches. This guide explains what hunger on Mounjaro means, your options for adjusting treatment in the UK, and the costs and access routes — whether you're on the NHS or exploring private prescription options.
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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 and Your Treatment Options
Returning hunger while on Mounjaro often signals that your body has adapted to your current dose, or it's time to escalate to the next therapeutic level. Mounjaro works through two hormone pathways — GIP and GLP-1 — to reduce appetite and support feeling fuller after meals. As your body adjusts, some patients experience reduced appetite suppression over weeks or months.
What this means for your treatment:
- Your prescriber may increase your dose — Mounjaro is typically escalated every 4 weeks, from 2.5 mg up to the maximum 15 mg once weekly
- You may have reached an optimal dose where appetite control plateaus — this is normal and weight loss can continue with diet and activity
- Your individual response may differ from clinical trial averages — dose titration is personalised
- Returning hunger doesn't mean the medication has failed — dose adjustment is part of standard treatment
The key is reporting this to your prescriber promptly so they can assess whether escalation is appropriate for you. You can use our GLP-1 weight loss calculator to track where you are in your weight loss journey and discuss results at your next appointment.
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.
Accessing Mounjaro in the UK — NHS vs Private Cost and Routes
NHS route: Mounjaro is available through specialist tier 3/4 weight management services following a GP referral. NICE has approved tirzepatide for NHS use, but availability and waiting times vary significantly by region — some areas have waiting lists of several months to over a year. There is no cost to you via the NHS, but you'll need to be referred and assessed as eligible (typically BMI ≥30 or 27+ with weight-related health conditions).
Private route: Private prescription costs typically range from £129–£320 per month depending on your dose and the pharmacy. You'll complete an online clinical assessment with a UK-licensed prescriber — if approved, your prescription is dispensed by a GPhC-registered pharmacy. The private route is faster (often within days) but requires upfront payment. Use our BMI calculator to check your eligibility before booking a consultation, and discuss dose options with your prescriber.
- 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 suddenly feeling hungry again on Mounjaro?
Hunger returning during Mounjaro treatment usually means your body has adapted to your current dose, or you've reached a plateau where appetite suppression naturally reduces. This is normal and doesn't mean the medication isn't working — dose escalation is standard practice. Your prescriber can assess whether increasing from your current dose is appropriate.
Can I switch from Mounjaro to Wegovy if I'm feeling hungry?
Some patients do switch between GLP-1 medications, though this is a prescriber decision. Mounjaro is a dual GIP and GLP-1 agonist, while Wegovy is GLP-1-only — they work through slightly different mechanisms. If hunger persists after dose escalation, your prescriber may discuss switching as an option, but dose increase is usually tried first.
How much does Mounjaro cost privately in the UK?
Private Mounjaro costs typically range from £129–£320 per month depending on your dose and provider. Lower doses (2.5–5 mg) are cheaper; higher doses (10–15 mg) cost more. Prices may vary between private providers, so it's worth comparing before booking. NHS access is free but requires referral and specialist assessment.
How quickly can I access Mounjaro privately in the UK?
Private access is usually fast — many patients receive a prescription within 3–7 days of completing an online clinical assessment. NHS access is slower, typically involving a GP referral, specialist appointment, and then waiting for treatment initiation (often weeks to months depending on your region).
What should I tell my prescriber about feeling hungry on Mounjaro?
Tell your prescriber exactly when the hunger returned, how long you've been on your current dose, and how your weight loss is progressing. Bring your weight records — if using our progress tracker, you can show this at your appointment. Your prescriber will likely recommend dose escalation, dietary adjustments, or monitoring before considering a medication change.
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.