What causes sulphur burps on Mounjaro?
Sulphur burps result from Mounjaro’s primary mechanism of action: slowing gastric emptying.
The medication mimics GLP-1 and GIP hormones, which naturally delay how quickly food moves from our stomach into the small intestine.
When food stays in your stomach longer than usual, bacterial fermentation increases, producing hydrogen sulfide gas.
This gas creates the distinctive ‘rotten egg’ smell that characterises sulphur burps. The process is similar to what happens when eggs or other sulphur-containing foods spoil.
Certain foods may increase the likelihood of sulfur burps on Mounjaro. High-protein foods like eggs, meat, and dairy contain sulphur-containing amino acids that could provide more raw material for bacterial fermentation.
Cruciferous vegetables such as broccoli, cabbage, and Brussels sprouts may also contribute to sulphur production.
Individual variation in sulphur burps
Not everyone on Mounjaro experiences sulphur burps, and the severity varies from person to person.
Factors that may influence your likelihood include your natural gastric emptying rate, gut bacteria composition, and dietary choices.
People with naturally slower digestion may experience more pronounced symptoms, while others might have fewer issues.
Our gut microbiome may also play a role, as certain bacterial strains are more efficient at producing hydrogen sulfide from sulfur-containing compounds.
How long do sulphur burps last on Mounjaro?
Patient reports suggest that sulphur burps often occur when starting Mounjaro or increasing doses.
The symptoms appear to subside as the digestive system adapts to slower gastric emptying, though the timeframe differs for everyone.
UK patient experiences shared in online forums suggest that sulphur burps often improve within the first few weeks at a new dose.
However, some individuals may experience occasional episodes throughout their treatment, particularly after eating certain foods.
If you’re experiencing persistent sulphur burps that don’t improve over time at a stable dose, this may indicate that your current dose needs adjustment.
Many people find that modifying their portion sizes or eating patterns helps manage symptoms.
Timing patterns throughout treatment
Patient reports suggest sulphur burps tend to follow a pattern during Mounjaro treatment, often appearing within the first few days after starting or increasing doses.
Subsequent dose escalations may trigger a return of sulphur burps, but many users report that later episodes are typically milder and shorter-lived than the initial experience.
By the time people reach their maintenance dose, most report that sulphur burps become less frequent or absent.
Relief strategies that work for sulphur burps
Based on patient experiences and what we know about digestion, several approaches can help manage sulphur burps.
Changes in eating habits
Many patients report that reducing sulphur-rich foods during the first few weeks of treatment or dose increases helps minimise sulphur burp occurrence.
Broadly speaking, we should aim to move away from consuming ultra-processed foods to eating diets based on whole foods on Mounjaro.
Our members generally report that most side effects are well-managed when eating meals based on whole foods.
You may not have to make any changes beyond this, as sulphur burps should subside after the body has adapted to the medication and your new eating habits.
However, if sulphur burps persist, some whole foods may also contribute to sulphur burps on Mounjaro, particularly in the early stages of treatment.
Consider temporarily limiting eggs, red meat, dairy products, and cruciferous vegetables, such as broccoli and cauliflower.
Focus on easily digestible options such as white rice, fruit, potatoes, non-cruciferous vegetables, and lean proteins like white fish or minced meat.
These foods may move through our stomach more quickly and are less likely to cause fermentation.
Avoiding carbonated drinks may help, as these can increase gastric pressure and make burping more frequent and uncomfortable.
Similarly, limiting ultra-processed foods rich in added fat or whole foods that are high in fibre during the adaptation period may be beneficial, as these take longer to digest.
Eating pattern adjustments
Eating smaller, more frequent meals may prevent food from accumulating in your stomach for extended periods.
Many patients find that portions about the size of their closed fist work better than traditional meal sizes.
Chewing food thoroughly and eating slowly can reduce the amount of air you swallow, which may contribute to burping.
Taking 20-30 minutes to finish a meal allows your stomach to signal when you’re full.
Stopping eating at least 3-4 hours before bedtime may help ensure your stomach has emptied before you lie down.
Lying flat with a full stomach can worsen gastric stasis and potentially increase fermentation.
Immediate relief techniques
When sulphur burps occur, several strategies often provide relief. Drinking warm water or herbal teas, such as ginger or peppermint, may help stimulate gastric motility and reduce trapped gas.
Light physical activity, such as a gentle 10-15 minute walk after meals, may encourage gastric emptying and prevent food stagnation.
Avoid vigorous exercise immediately after eating, as it can make nausea worse.
Some patients find that over-the-counter gas relief products help with general digestive discomfort, though you should check with your pharmacist about interactions with other medications.
Timing your Mounjaro injection
Some people report that injecting Mounjaro in the evening rather than morning helps minimise daytime sulphur burps.
Alternatively, if evening injections interfere with sleep, try injecting several hours after your largest meal of the day. This timing may help prevent the medication’s peak effects from coinciding with your next large meal.
Still, there’s no clinical evidence showing that different timing of injections can relieve symptoms. So, it’s best to experiment and see what works for you.
When to seek medical help for sulphur burps
While sulphur burps are generally considered harmless, certain symptoms warrant medical attention.
Contact your healthcare provider if sulphur burps persist without improvement or worsen over time, as this may indicate that your current dose needs adjustment.
Seek immediate medical help if sulphur burps are accompanied by severe vomiting that prevents you from keeping fluids down, signs of dehydration such as dizziness or reduced urination, or severe abdominal pain that doesn’t improve with rest.
NHS guidance recommends consulting your GP if gastrointestinal side effects significantly impact your daily functioning or quality of life.
Take home message
Sulphur burps on Mounjaro are a reported side effect that appears to be temporary for most people.
They result from slower gastric emptying, which allows increased bacterial fermentation in your stomach.
Many patients find that combining dietary modifications (reducing sulphur-rich foods), changes in eating habits (smaller, more frequent meals based on whole foods), and targeted relief strategies helps manage symptoms when they occur.
Many people find suggest that sulphur burps become less frequent and severe as the body adapts to Mounjaro.
However, if symptoms persist or significantly impact your daily life, speak with your healthcare provider about potential adjustments.
Second Nature’s medication programme
Second Nature provides Mounjaro as part of our Mounjaro weight-loss programme.
Why choose Second Nature over other medication providers, assuming you’re eligible?
Because peace of mind matters.
We’ve had the privilege of working with the NHS for over eight years, helping people across the UK take meaningful steps toward a healthier, happier life.
Our programmes are designed to meet people where they are, whether that means support with weight loss through compassionate one-to-one health coaching, or access to the latest weight-loss medications (like Mounjaro) delivered alongside expert care from a multidisciplinary team of doctors, psychologists, dietitians, and personal trainers.
At the heart of everything we do is a simple belief: real, lasting change comes from building better habits, not relying on quick fixes.
We’re here to support that change every step of the way.
With over a decade of experience, thousands of lives changed, and a long-standing record of delivering programmes used by the NHS, we believe we’re the UK’s most trusted weight-loss programme.
We hope to offer you something invaluable: peace of mind and the support you need to take that first step.
Please note: We generally recommend speaking with your GP/doctor before you start taking any new medication like Mounjaro. If you do sign up for Second Nature's Mounjaro programme, then we'll also send your GP a letter to let them know you've started a medication-supported weight-loss journey.
