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
Understanding Egg Burps on Mounjaro — UK Access & Costs
Egg burps are a distinctive side effect some people experience while taking Mounjaro (tirzepatide) — a prescription-only weight management injection licensed in the UK. This unusual digestive symptom typically occurs in the early weeks of treatment as your body adjusts to the medication. If you're considering Mounjaro or currently taking it, understanding both this side effect and how to access the medication in the UK is important. Use our free GLP-1 weight loss calculator to estimate potential outcomes, and our free BMI calculator to check your eligibility for treatment.
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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.
What Causes Egg Burps and How to Manage Them
Egg burps (scientifically called "eggy burps") occur because Mounjaro slows gastric emptying — the speed at which food moves from your stomach into your small intestine. When food, especially protein and fatty foods, sits in the stomach longer, bacteria can ferment it, producing sulphur-like compounds. These are released as burps that smell distinctly of eggs or sulphur.
- Typically occur 1–4 weeks after starting Mounjaro or increasing your dose
- More common at higher doses (10 mg and above)
- Often improve or resolve as your body adapts (usually by weeks 4–6)
- Triggered by fatty, protein-rich foods like eggs, cheese, and meat
- Managed by eating smaller meals, avoiding trigger foods, and staying hydrated
While unpleasant, egg burps are not dangerous and are a recognised side effect documented in clinical trials. Your prescriber can advise if symptoms persist beyond the initial adjustment period.
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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
In the UK, Mounjaro access depends on your route. NHS route: You can be referred to a specialist tier 3 weight management service by your GP if you meet eligibility criteria (BMI ≥30, or BMI 27–29.9 with weight-related health conditions). However, NHS availability is extremely limited and waiting lists in many areas are very long — sometimes months to years. Private route: Available through online consultations with UK-licensed prescribers. Private treatment is faster but costs approximately £130–£320 per month depending on your dose. Both routes require a clinical assessment, and Mounjaro requires a valid UK prescription dispensed by a registered pharmacy. The tirzepatide dose you're prescribed affects the total cost, with higher doses costing more.
- 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 do egg burps last when taking Mounjaro?
Egg burps typically resolve within 2–6 weeks as your digestive system adapts to the medication. Some people experience them only during dose increases. If they persist beyond 6 weeks, speak to your prescriber — they can advise on dietary adjustments or whether your dose needs reviewing.
How much does Mounjaro cost privately in the UK?
Private Mounjaro treatment typically costs £130–£320 per month, depending on your dose (2.5 mg to 15 mg weekly). Starting doses cost less than maintenance doses. Prices vary slightly between online prescribing services. Always check the full cost before starting treatment, including any consultation fees.
Can I get Mounjaro on the NHS in the UK?
Mounjaro is available through NHS specialist weight management services (tier 3), but access is very limited and varies significantly by region. Your GP can refer you if you meet eligibility criteria, but waiting times are often very long. Private prescription is a faster alternative if you want to start treatment immediately.
What foods trigger egg burps on Mounjaro?
Fatty and protein-rich foods are most likely to trigger egg burps — eggs, cheese, fatty meat, fried foods, and dairy products. Keeping a food diary can help identify your specific triggers. Eating smaller, more frequent meals and staying hydrated often helps reduce the severity.
Do I need a prescription to buy Mounjaro in the UK?
Yes, Mounjaro is prescription-only in the UK. You cannot buy it without a valid prescription from a UK-licensed prescriber. This applies whether you're accessing it through NHS specialist services or private online consultations. Always check that any provider is GPhC-registered.
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.