Switching from Mounjaro to Wegovy: What You Need to Know

Have you recently started Mounjaro and found yourself dealing with unexpected and uncomfortable belching that smells a bit like rotten eggs? If so, you're not alone - and you're certainly not imagining it. These “sulphur burps” can be distressing, especially when you're otherwise motivated and hopeful about your weight loss journey.

Based on a survey in the UK, many patients reported that they felt blindsided by this peculiar side effect. One minute, they’re feeling hopeful with a powerful new weight loss injection, and the next, they’re wondering if something’s gone wrong with their digestive system. And perhaps you're wondering the same - Is this normal? Will it go away? And what can I do about it?

This guide was created to address those very concerns. We’ll explore why Mounjaro (tirzepatide) might cause sulfur burps, how common and manageable this issue is, and what you can do to ease the discomfort without compromising your progress. Let's unpack the science behind it and, more importantly, the practical ways to feel better.

Mounjaro (Tirzepatide) 

Mounjaro has quickly become one of the most talked-about advances in the treatment of obesity and type 2 diabetes. Approved by MHRA, it has brought fresh hope to individuals struggling with weight loss and metabolic health.

Its arrival on the NHS and in private weight loss clinics has been met with enthusiasm, especially because of its dual-action mechanism that promotes both improved blood sugar control and significant weight loss. For many, it offers the possibility of reclaiming health, mobility, and confidence.

But with all medications, especially newer ones, there can be surprises. One of these is gastrointestinal discomfort, and in particular, foul-smelling burps that some describe as tasting or smelling like sulphur. While not dangerous, they can be off-putting and even socially disruptive.

Understanding How Mounjaro Works

To understand why such a symptom might occur, it helps to know a bit about how Mounjaro functions in the body. Tirzepatide is what we call a dual incretin agonist. It mimics the actions of two naturally occurring gut hormones - GLP-1 (glucagon-like peptide-1) and GIP (glucose-dependent insulinotropic polypeptide). Together, these hormones help regulate blood sugar after eating, reduce appetite, and, importantly, slow down how quickly food moves through the stomach.

This slowing down of digestion is beneficial for weight loss, as it helps you feel fuller for longer and keeps post-meal blood sugars steady. But it can also lead to side effects, including nausea, bloating, and in some cases, excessive or unpleasant-smelling burping.

Mounjaro is approved for use in adults with type 2 diabetes and weight loss in individuals with a BMI of 30 or more, or 27 with weight-related health conditions. It should always be prescribed and monitored by a qualified healthcare professional who can guide you through its benefits and potential challenges.

What Are Sulphur Burps and Why Do They Happen?

Sulphur burps - sometimes called rotten egg burps - occur when gas containing hydrogen sulfide is released from the stomach and expelled through belching. The smell is distinctive and often compared to decaying eggs. It's not harmful in small amounts, but it can be unpleasant and, for some, embarrassing.

Patients describe them as sudden, foul-smelling belches that seem to come out of nowhere, sometimes accompanied by a sour or metallic taste. They can happen after meals or even on an empty stomach, and in some cases, they disrupt sleep or social activities.

Although they aren’t included as a common side effect in Mounjaro’s official safety profile, reports of sulphur burps have emerged among users, particularly those in online forums, weight loss support groups, and anecdotal clinic feedback. While not everyone will experience them, they are a recognised concern and likely tied to how the medication alters digestion.

Real-World Experiences

• User Feedback: Sulphur burps are frequently discussed in patient forums and social media. Experiences vary from mild annoyance to severe discomfort, but most participants note improvement with dietary or behavioural adjustments.
• Related Symptoms: Some users report sulphur burps alongside stomach discomfort, diarrhoea, or bloating, especially after dose changes.

The Link Between Mounjaro and Sulphur Burps: What's Going On Inside Your Gut?

One of Mounjaro’s main effects is slowing gastric emptying. That means food stays in your stomach and upper digestive tract longer than usual. While this helps you feel full and eat less, it also gives gut bacteria more time to break down the food, especially proteins and certain carbohydrates. When this bacterial fermentation happens, it can release gases like methane, hydrogen, and hydrogen sulfide.

Hydrogen sulfide is the culprit behind the rotten egg smell. The risk of producing this gas increases if your diet contains a lot of high-sulphur foods - think eggs, onions, garlic, cruciferous vegetables like cabbage and broccoli, red meats, and certain dairy products. Add in high-fat meals, which can slow digestion even further, and the stage is set for fermentation and gas production.

It's also important to note that every individual has a unique gut microbiome. Some people naturally have more sulphur-producing bacteria, which might explain why only certain individuals experience this side effect on Mounjaro, even when eating similar diets.

Managing Sulphur Burps While on Mounjaro: What You Can Do?

If you’re dealing with sulphur burps while taking Mounjaro, you don’t need to suffer in silence. There are several practical ways to ease the issue without having to stop the medication.

• One of the most effective first steps is to look at your diet. Reducing your intake of sulphur-rich foods can make a noticeable difference. You might not need to eliminate them, but cutting back on frequent servings of eggs, red meats, onions, and cruciferous vegetables for a few weeks may help reduce the smell and frequency of burps. 

Similarly, opting for lighter, lower-fat meals can support faster digestion. Eating smaller meals more frequently throughout the day may prevent your stomach from becoming overly full and reduce the fermentation time.

• Hydration is another simple but powerful strategy. Drinking enough water helps support digestion and gut motility. Some people also find that warm fluids like herbal teas ease bloating and burping.
• Chewing food thoroughly and eating slowly reduces the amount of air swallowed during meals, which can help prevent excessive gas formation. Avoid fizzy drinks and don’t talk with your mouth full - both introduce unnecessary air into the digestive tract.

When Remedies Can Help: Medicines and Supplements

If dietary changes and mindful eating don’t fully resolve the issue, certain over-the-counter remedies may offer relief, but they should be used with guidance from your pharmacist or GP.

Simethicone-based products such as Wind-eze can help break up gas bubbles in the gut, making it easier for your body to expel them naturally. It also comes in our SheMed support pack.

Some people find benefit in taking probiotics, which can help rebalance gut bacteria. Not all probiotic strains are effective for this purpose, so look for ones supported by evidence in digestive health - your pharmacist or dietitian can recommend appropriate UK-approved brands.

Another option is bismuth subsalicylate (like Pepto-Bismol), which can bind to hydrogen sulfide and neutralise the smell. However, this should only be used occasionally and with medical guidance, especially if you’re on other medications, as it can interact with drugs.

Activated charcoal is sometimes suggested, but it can also bind to medications and nutrients, interfering with absorption. It's best to approach this option cautiously and only after speaking with your doctor.

When to Speak to Your Doctor: Knowing What’s Normal and What’s Not

While sulphur burps are usually a benign and manageable side effect, there are situations where you should seek medical advice. If your symptoms become persistent, worsen over time, or start to impact your daily life, speak to your GP or prescribing clinician. You may need a review of your dosage, further dietary support, or even a check for other digestive issues such as gastritis or bacterial overgrowth.

In some cases, sulphur burps could be a sign of an underlying gastrointestinal condition, particularly if they’re accompanied by red flag symptoms like severe abdominal pain, ongoing nausea or vomiting, diarrhoea or constipation, fever, unexplained weight loss, or blood in your stool or vomit.

Don’t wait to report these symptoms. Mounjaro may need to be paused or adjusted, and your doctor can ensure there’s nothing more serious occurring in the background.

Conclusion

Starting Mounjaro is a significant and often hopeful step in addressing weight or metabolic health challenges. While it can come with surprises like sulphur burps, it’s important to remember that most side effects are manageable - and often temporary. You don’t have to choose between relief and results. 

With the right strategies, support, and awareness, you can continue progressing on your weight loss journey without being held back by uncomfortable symptoms. Stay in regular touch with your healthcare team. 

Don’t hesitate to ask questions or voice concerns, especially about digestive side effects. You are not alone, and your concerns are valid. Mounjaro is one tool in a broader toolkit that includes lifestyle changes, nutrition, movement, and mental well-being. Together, these elements can help you achieve your goals in a sustainable, empowered way.

FAQs

1. Are sulphur burps a normal side effect of Mounjaro?

While not officially listed as a common side effect in clinical trials, sulphur burps have been reported by some Mounjaro users. They are likely linked to the way the medication slows digestion, which can increase gas production in the gut. The symptom is usually manageable and not harmful.

2. What foods should I avoid if I’m experiencing sulphur burps on Mounjaro?

Reducing foods high in sulphur - like eggs, onions, garlic, cabbage, broccoli, and red meat - may help. Limiting high-fat meals and fizzy drinks can also reduce burping. Keeping a food diary can be useful for identifying personal triggers.

3. Do I need to stop taking Mounjaro if I have sulphur burps?

Not usually. Most cases improve with dietary changes and supportive measures. However, if the symptoms are severe, persistent, or affecting your quality of life, speak to your prescribing doctor. They may suggest adjustments or further assessment.

References

1. British National Formulary (BNF). (2024). Tirzepatide: Drug monograph. Retrieved from https://bnf.nice.org.uk/drugs/tirzepatid
   
2. Mayo Clinic. (2023). Sulfur burps: Causes and remedies. Retrieved from https://www.mayoclinic.org/diseases-conditions/gas-and-gas-pains/in-depth/gas-and-gas-pains/art-20044739
   
3. MedlinePlus. (2024). Tirzepatide injection. U.S. National Library of Medicine. Retrieved from https://medlineplus.gov/druginfo/meds/a623037.html (Note: URL verified through U.S. National Library of Medicine) ‍
4. Monash University. (2022). Gut microbiome and digestion. Monash FODMAP Diet. Retrieved from https://www.monashfodmap.com/ 
5. NHS (2024). GLP‑1 receptor agonists: Side effects and safety. Retrieved from https://www.nhs.uk/medicines/glp-1-receptor-agonists/ 
6. Zhou, M., Wang, X., Li, J., & Liu, Y. (2023). Gastrointestinal side effects of GLP‑1 and GIP receptor agonists: Mechanisms and management. Pharmacological Research, 190, 106719. https://doi.org/10.1016/j.phrs.2023.106719

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“Why don’t I want food the way I used to?” It’s a quiet question many people on GLP-1 medications like Wegovy, or Mounjaro find themselves asking - not out of distress, but with a sense of surprise. 

In recent years, GLP-1 receptor agonists - like Wegovy and Mounjaro have surged in popularity, marking a paradigm shift in the way clinicians manage obesity and type 2 diabetes. Once reserved for glycaemic control, these medications are now heralded as revolutionary tools in weight management, prompting widespread headlines and heated dinner-table debates. From celebrity endorsements to NHS programmes, the influence of GLP-1s stretches far beyond clinics.

Clinical benefits are clear: reductions in appetite, improved glycaemic markers, and meaningful weight loss (often between 10–20% of total body weight). But beneath this success story lies a more nuanced truth - these drugs do more than suppress hunger. They appear to recalibrate how users think about, crave, and emotionally respond to food. It’s no longer just about portion control; it’s about fundamentally shifting one’s relationship with eating.

This blog dives deeper into that shift - from gut mechanisms and brain signalling to emotional complexities and cultural implications. We’ll explore how GLP-1s dampen desire, reshape social dynamics, and force users to confront food in new ways - and what this means for the future of eating.

The Science of Satiety: How GLP-1s Work Physiologically

GLP-1 receptor agonists mimic a hormone naturally released in the gut after eating. This gut-derived peptide, glucagon-like peptide-1 (GLP-1), plays several critical roles in managing hunger and blood sugar.

Mimicking Natural Hormones
These drugs stimulate the GLP-1 receptors in the pancreas and brain. They help regulate insulin release, suppress glucagon (which raises blood sugar), and send signals to the brain that the body is full.

Delayed Gastric Emptying
GLP-1s slow how quickly food exits the stomach. This delay prolongs the sensation of fullness and reduces the desire to snack frequently - often resulting in a natural reduction in meal frequency.

Appetite Suppression via Brain Signalling
They impact the hypothalamus, a brain region involved in hunger and satiety. Users often describe feeling full earlier during meals and no longer needing snacks between meals.

Blood Sugar Regulation
By enhancing insulin secretion and lowering post-meal glucose spikes, GLP-1s also stabilise energy levels, which can indirectly reduce sugar cravings and mood-related eating episodes.

Initial Impact on Eating Habits
Clinical trials and observational studies suggest a 20–30% reduction in daily calorie intake. This manifests as smaller portions, fewer snacks, and less desire to eat emotionally. The reduction isn’t forced - it’s passive, which often surprises new users.

Here’s how they help reshape eating behaviour:

• Silencing Food Noise: The constant mental chatter about eating, cravings, and meal planning fades into the background.
  
• Reduced Reward Response: High-calorie foods like sweets and salty snacks become less emotionally appealing.
  
• Disruption of Emotional Eating: Eating becomes more driven by true hunger rather than stress, boredom, or habit.
  
• Breaking Habit Loops: Automatic patterns like snacking or bingeing often weaken without conscious effort.
  
• Mental Clarity: With food taking up less mental space, users often report better focus and emotional balance.
  
• Support Still Matters: While GLP-1s are effective, long-term change may require therapy or behavioral strategies to address emotional triggers.

In short, GLP-1s do more than curb appetite - they help reset your brain’s relationship with food, opening the door to a more mindful and sustainable approach to eating.

Navigating the New Normal: Challenges and Opportunities

While the benefits are significant, life on a GLP-1 also comes with challenges - especially when food is woven into personal identity or cultural traditions.

Social Implications
Imagine sitting at a Christmas feast or Sunday roast with loved ones and feeling disinterested in the spread. Users on social media report discomfort at family meals, where eating is expected and emotional significance is high. Food-centric events can become stressful.

Food Identity & Psychological Adjustment
For those who identify as foodies or use cooking as creative expression, this shift can be jarring. Navigating a life where food no longer sparks joy or where choices are driven by function rather than desire can feel like a loss of identity.

Mindful Eating
By quieting cravings, GLP-1s create space to truly listen to hunger cues. Users can develop a more intuitive approach to nourishment - eating when the body asks, not when emotions command.

Prioritising Nutritional Quality
With lower intake, nutritional density matters more. The guidelines from the NHS and British Dietetic Association suggest focusing on lean proteins, fibre-rich vegetables, and fortified foods. Every bite must count.

Redefining Indulgence
Indulgence may become less about decadence and more about connection - savouring small amounts of a favourite dish, appreciating texture, or sharing meaningful conversations over meals.

Professional Support
The NHS is increasingly supporting GLP-1 patients with multidisciplinary guidance including dietitians, diabetes specialists, and psychologists. This holistic approach ensures both physical and emotional wellbeing are prioritised.

The Long View: What Happens When the Medication Stops?

GLP-1 medications offer powerful support in reshaping eating habits and reducing cravings - but what happens when you stop taking them?

For many, the mental and physical effects begin to fade gradually. Appetite may increase, food noise can return, and emotional eating patterns might re-emerge - especially if the underlying behaviours or triggers weren't fully addressed during treatment.

Rebound Weight & “Food Noise” Return
Studies indicate that when GLP-1 treatment ends, hunger signals and cravings can resurface. Weight regain is common unless new habits are firmly embedded.

Learning from the GLP-1 Phase
However, those who used this time to cultivate healthier habits - practising mindful eating, breaking emotional dependencies, living an active lifestyle, and learning how to nourish themselves - may sustain benefits longer. The medication can act as a scaffold while behavioural change is built.

Ongoing Support is Key
Behavioural therapy, nutrition counselling, and peer support are essential in transitioning off medication. The goal? To internalise changes so they persist independently of pharmacological support.

Conclusion

GLP-1 receptor agonists are more than appetite suppressants. They are reshaping how individuals experience food - from physical cravings to emotional fulfilment. For many, this is life-changing; for others, it presents unexpected psychological adjustments.

Like any tool, these medications require intention, support, and context. They can help lay the foundation for healthier eating patterns, but sustaining those patterns demands effort beyond the prescription. For long-term success, medical guidance must be complemented with emotional insight and cultural sensitivity.

Ultimately, GLP-1s invite us to rethink our relationship with food - not just what we eat, but why, when, and how food fits into our lives. It's not just about fullness - it's about finding meaning in what remains beyond the bite.

FAQs

1. Why do I feel less interested in food on GLP-1 medications?
GLP-1s affect brain centres involved in hunger, reward, and motivation.
They don’t just reduce appetite - they can change how you emotionally and mentally respond to food.

2. Is it normal to feel disconnected from food I once loved?
Yes, many users report feeling emotionally neutral about previously craved foods. This shift can be surprising, even unsettling, but it’s a known effect of GLP-1 therapy.

3. Can GLP-1s affect social eating or shared meals?
Absolutely. Smaller portions or lack of appetite can impact social interactions and cultural routines. Planning ahead and communicating openly can help maintain connection while adjusting.

4. Will my appetite and food enjoyment return if I stop the medication?
For most people, appetite gradually returns after stopping GLP-1s. However, some emotional or behavioural shifts around food may persist, depending on your journey.

References

1. Zheng, Z., et al. (2024). Glucagon-like peptide-1 receptor: mechanisms and latest advancements in treating various diseases. Signal Transduction and Targeted Therapy, 9, Article 91. https://doi.org/10.1038/s41392-024-01931-z
2. Nauck, M. A., Quast, D. R., Wefers, J., & Meier, J. J. (2021). GLP-1 receptor agonists in the treatment of type 2 diabetes: state-of-the-art. Trends in Endocrinology & Metabolism, 32(11), 815-830. https://doi.org/10.1016/j.tem.2021.08.006
3. Prasad-Reddy, L., & Isaacs, D. (2015). A clinical review of GLP-1 receptor agonists: efficacy and safety for type 2 diabetes. Diabetes Therapy, 6(2), 109–145. https://doi.org/10.1007/s13300-015-0118-6
4. Zhao, X., et al. (2021). GLP-1 receptor agonists: beyond their pancreatic effects. Frontiers in Endocrinology, 12, 721135. https://doi.org/10.3389/fendo.2021.721135
5. Jerlhag, E. (2025). GLP-1 receptor agonists: promising therapeutic targets for alcohol use disorder and beyond. Endocrinology, 166(4), bqaf028. https://doi.org/10.1210/endocr/bqaf028‍
6. Moiz, A., et al. (2025). Mechanisms of GLP-1 receptor agonist-induced weight loss. American Journal of Physiology - Regulatory, Integrative and Comparative Physiology, 328(1), R43-R55. https://doi.org/10.1152/ajpregu.00189.2024