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 Stop Mounjaro Sulphur Burps
Sulphur burps (rotten egg-smelling belches) are an occasional side effect reported by some people taking Mounjaro for weight management. While not everyone experiences this, understanding what causes it and how to manage it can help. This guide explains the mechanism behind sulphur burps on Mounjaro, practical strategies to reduce them, and how this side effect compares when taking Wegovy or other GLP-1 medications. Your GP or prescriber can advise on individual management 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.
What Causes Sulphur Burps on Mounjaro?
Sulphur burps occur due to how tirzepatide (Mounjaro's active ingredient) affects digestion. As a dual GIP and GLP-1 receptor agonist, Mounjaro slows gastric emptying — the rate at which food moves from your stomach into your small intestine. When food sits in the stomach longer, bacterial fermentation increases, producing hydrogen sulphide gas, which creates that characteristic rotten egg smell.
This is particularly common in the first weeks of treatment or after dose increases, as your digestive system adjusts. The effect typically diminishes over time as your body acclimatises to the medication. Other digestive side effects that commonly occur alongside sulphur burps include bloating, indigestion, and constipation or diarrhoea.
- Delayed stomach emptying is the primary mechanism
- More likely in early treatment weeks
- Usually improves as tolerance builds
- Can be worse after fatty or heavy meals
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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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Managing Sulphur Burps and Mounjaro vs Wegovy
Practical strategies to reduce sulphur burps include dietary adjustments and lifestyle modifications. Eat smaller, more frequent meals rather than large ones; avoid fatty, greasy, and heavily processed foods; stay hydrated with water between meals; eat slowly and chew thoroughly; and consider eating foods that support digestion like ginger, peppermint tea, or probiotic yoghurt. Some people find that gentle walking after meals helps stomach motility.
Comparing Mounjaro and Wegovy: Both are prescription-only GLP-1-based medications that slow gastric emptying, so both can cause sulphur burps. Clinical trial data from SURMOUNT (Mounjaro) and STEP (Wegovy) show similar rates of digestive side effects. Since Mounjaro is a dual GIP+GLP-1 agonist while Wegovy is GLP-1 only, individual tolerability varies. Your prescriber will assess which is more suitable based on your health profile and how your body responds.
When to contact your GP: If sulphur burps are severe, persistent, or accompanied by significant nausea, vomiting, or abdominal pain, contact your GP. These may indicate a separate digestive issue unrelated to the medication. Your prescriber may adjust your dose titration schedule — slowing the escalation between Mounjaro doses — or switch to an alternative weight management option if side effects become intolerable.
Never stop taking Mounjaro without medical guidance. The condition usually improves within weeks to months as your body adjusts. Use our free GLP-1 weight loss calculator to understand expected outcomes with either medication, and discuss tolerability concerns with your prescriber at each dose increase.
- 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.
Are sulphur burps a sign that Mounjaro isn't working?
No. Sulphur burps are a side effect of how the medication affects digestion, not an indicator of efficacy. Some people experience them, others don't. The medication's weight loss effects are separate from digestive side effects. Most people find sulphur burps improve over time as their body adjusts to the tirzepatide dose.
Does Wegovy cause sulphur burps as often as Mounjaro?
Both medications can cause sulphur burps because both slow gastric emptying. Clinical trial data shows similar rates of digestive side effects between them. However, individual responses vary significantly. Some people tolerate Wegovy better, others Mounjaro. Your prescriber will assess which is more suitable after a clinical assessment.
Can I take anything to stop sulphur burps immediately?
There's no instant supports, but several strategies help: eat smaller meals, avoid fatty foods, stay hydrated, drink peppermint or ginger tea, and take probiotics. Simethicone (anti-gas medication) and digestive enzymes may provide relief for some people. Always check with your GP before starting any new supplement or medication alongside Mounjaro.
Should I stop taking Mounjaro if sulphur burps are really bad?
Never stop taking Mounjaro without contacting your prescriber first. While sulphur burps are uncomfortable, they're not dangerous and typically improve as your body adjusts. Your prescriber may slow your dose titration schedule or explore alternative weight management options if side effects are intolerable.
Do sulphur burps on Mounjaro mean my dose is too high?
Not necessarily. Sulphur burps can occur at any dose as your digestive system adjusts. They're most common when starting or escalating doses. If they persist beyond a few weeks at a stable dose, contact your GP. Your prescriber can advise whether a dose adjustment or dietary modification might help.
Ready to take control of your weight loss journey?
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