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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How to Get Rid of Sulfur Burps on Mounjaro
Sulfur burps (rotten egg-smelling belching) are a common side effect of Mounjaro (tirzepatide) in some users, particularly during the early stages of treatment or after dose increases. These burps occur because Mounjaro slows how quickly food moves through your stomach, allowing bacteria to ferment undigested food. Whilst uncomfortable, they typically subside as your body adjusts to the medication. This guide explains what causes them, practical management strategies, and how this side effect compares between Mounjaro and Wegovy (semaglutide).
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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 Sulfur Burps Occur on Mounjaro and Wegovy
Sulfur burps happen because both Mounjaro and Wegovy slow gastric emptying — the speed at which food passes from your stomach into your small intestine. This effect is intentional (it helps you feel fuller), but it can allow food to sit in your stomach longer, where bacteria produce hydrogen sulphide gas, creating that distinctive rotten egg smell.
Mounjaro (a dual GIP and GLP-1 receptor agonist) and Wegovy (GLP-1 receptor agonist only) both cause this side effect, though frequency and severity vary between individuals. The effect is usually strongest during the first 4–8 weeks of treatment or after a dose increase, and typically improves as your body adapts.
- More common when eating fatty or greasy foods
- More common when eating large meals
- Usually temporary — most users report improvement by weeks 8–12
- Affects roughly 5–15% of users significantly, though mild burping is more common
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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.
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Practical Management Strategies and Mounjaro vs Wegovy Comparison
Immediate management strategies include eating smaller, more frequent meals and avoiding fatty, greasy, and high-sulphur foods (eggs, meat, cruciferous vegetables like broccoli). Stay hydrated, eat slowly, and consider ginger tea or peppermint, which some users find helpful for digestive comfort.
Regarding Mounjaro vs Wegovy: clinical trial data doesn't show a clear difference in sulfur burp frequency between the two medications, though individual experiences vary. Your GP or prescriber can help determine which is more suitable based on your overall tolerability profile. Use our GLP-1 weight loss calculator to explore projected outcomes with either medication, and consider discussing side effect profiles with your prescriber before choosing.
- 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 sulfur burps last on Mounjaro?
Most users experience improvement within 4–12 weeks as their body adapts. If sulfur burps persist beyond 12 weeks or worsen, contact your GP — it may indicate gastroparesis or another digestive issue requiring medical assessment.
Are sulfur burps more common on Mounjaro than Wegovy?
Clinical trial data doesn't show a significant difference in frequency between Mounjaro and Wegovy. Individual variation is high. Both medications slow gastric emptying, which causes this side effect. Your prescriber can help assess which is better suited to you personally.
What foods should I avoid to reduce sulfur burps?
Avoid fatty, greasy, high-sulphur, and high-fibre foods (eggs, meat, cruciferous vegetables, beans). Eat smaller, frequent meals instead of large ones. Ginger tea and peppermint may help some users. Staying hydrated also supports digestive comfort.
Should I stop taking Mounjaro if I get sulfur burps?
No — do not stop without speaking to your prescriber. Sulfur burps are usually temporary and manageable with dietary adjustments. If they're severe or don't improve after 12 weeks, contact your GP to discuss options, including possible medication adjustment.
Are sulfur burps a sign that Mounjaro isn't working?
No. Sulfur burps are a side effect, not an indicator of efficacy. Mounjaro works through appetite suppression and metabolic effects. Side effects and weight loss outcomes are separate. Your prescriber will monitor your progress through weight checks and clinical assessment.
Ready to take control of your weight loss journey?
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