Burping with a rotten egg smell whilst taking Ozempic (semaglutide) is an unpleasant gastrointestinal side effect reported by some patients. These 'sulphur burps' occur when hydrogen sulphide gas is released during belching, typically resulting from bacterial breakdown of sulphur-containing proteins in the digestive tract. Ozempic, a GLP-1 receptor agonist licensed in the UK for type 2 diabetes, slows gastric emptying as part of its therapeutic action, which may prolong food transit and increase bacterial fermentation. Whilst distressing, sulphur burps are generally benign and often improve with dietary modifications and gradual dose escalation. Understanding the mechanisms behind this side effect and implementing practical management strategies can help patients continue their diabetes treatment effectively whilst minimising discomfort.

Why Ozempic Can Cause Sulphur Burps and Rotten Egg Smell

Ozempic (semaglutide) is a glucagon-like peptide-1 (GLP-1) receptor agonist licensed in the UK for the treatment of type 2 diabetes mellitus. A higher dose formulation of semaglutide (Wegovy) is separately licensed for weight management. Whilst effective in improving glycaemic control, Ozempic is associated with a range of gastrointestinal side effects, including nausea, vomiting, diarrhoea, and belching (eructation).

Some patients report experiencing 'sulphur burps'—belching with an unpleasant rotten egg odour. This occurs when hydrogen sulphide gas is released during belching. This gas is produced by the breakdown of sulphur-containing proteins and amino acids (such as cysteine and methionine) by bacteria in the gastrointestinal tract. The mechanism by which Ozempic might contribute to this phenomenon is likely multifactorial, though direct evidence specifically linking semaglutide to sulphur burps is limited. Semaglutide slows gastric emptying, which is part of its therapeutic action in promoting satiety. However, delayed gastric emptying means food remains in the stomach for longer periods, potentially allowing increased bacterial fermentation and gas production.

Additionally, changes in gut motility may occur during GLP-1 receptor agonist therapy. These changes could theoretically affect digestive processes, though specific effects on the gut microbiome with semaglutide are not well established. It is important to note that whilst sulphur burps are unpleasant, they are not typically dangerous in isolation. Patients should be reassured that gastrointestinal side effects often improve over time as the body adjusts to the medication, particularly if dose escalation is gradual as recommended in the prescribing information.

Managing Sulphur Burps While Taking Ozempic

Effective management of sulphur burps involves a combination of lifestyle modifications, dietary adjustments, and symptomatic relief measures. Patients experiencing this side effect should first ensure they are following the recommended dose escalation schedule for Ozempic. The approved dosing regimen begins at 0.25 mg once weekly for four weeks (an initiation dose to improve tolerability), then increases to 0.5 mg once weekly, with further increases to 1 mg or 2 mg if needed for glycaemic control.

Practical strategies to reduce sulphur burps include:

• Eating smaller, more frequent meals rather than large portions, which can overwhelm the already-slowed digestive system

• Chewing food thoroughly and eating slowly to aid digestion and reduce the amount of air swallowed

• Staying well-hydrated throughout the day, as adequate fluid intake supports digestive function

• Avoiding carbonated beverages, which introduce additional gas into the digestive tract

• Taking a short walk after meals to encourage gentle physical activity, which may support digestion

Some patients consider over-the-counter remedies such as simethicone (an anti-foaming agent that helps break up gas bubbles). Speak to a pharmacist before trying these products, as evidence for their efficacy specifically in GLP-1-related symptoms is limited. Activated charcoal is sometimes suggested but should be used with caution as it can turn stools black and may reduce the absorption of other oral medications. Probiotic supplements have theoretical benefits, but there is currently insufficient evidence to recommend specific products for this indication.

If sulphur burps persist despite these measures or significantly impact quality of life, patients should discuss the issue with their prescribing clinician. In some cases, temporarily reducing the dose or considering alternative treatment options may be appropriate. It is essential that patients do not discontinue Ozempic without medical guidance, as this could compromise diabetes management.

When to Seek Medical Advice About Digestive Side Effects

Whilst sulphur burps alone are generally benign, they may occasionally signal more significant gastrointestinal issues that require medical assessment. Patients should contact their GP or diabetes specialist nurse if sulphur burps are accompanied by:

• Severe or persistent abdominal pain, particularly if localised or worsening

• Persistent vomiting that prevents adequate fluid or medication intake

• Signs of dehydration, including dark urine, dizziness, or reduced urine output

• Bloody or black stools, which may indicate gastrointestinal bleeding

• Unexplained fever or signs of infection

• Severe diarrhoea lasting more than 48 hours

• Pain in the upper right abdomen, jaundice (yellowing of skin/eyes), pale stools, which may indicate gallbladder problems

• Severe abdominal distension with inability to pass stool or gas, which could suggest bowel obstruction

Acute pancreatitis is a rare but serious adverse effect associated with GLP-1 receptor agonists, including Ozempic. Patients should seek urgent medical attention if they experience severe, persistent abdominal pain (often radiating to the back), accompanied by nausea and vomiting. The MHRA advises that semaglutide should be discontinued if pancreatitis is suspected, and it should not be restarted if pancreatitis is confirmed.

Additionally, gastroparesis (severe delayed gastric emptying) has been reported in association with GLP-1 receptor agonists. Symptoms suggestive of gastroparesis include persistent nausea, vomiting of undigested food hours after eating, early satiety, and significant abdominal bloating. These symptoms warrant medical review.

Patients should also inform their healthcare provider if gastrointestinal side effects prevent them from taking other essential medications or if they experience significant weight loss beyond their target, as dose adjustment may be necessary. For urgent concerns outside of normal hours, contact NHS 111 or attend A&E if severely unwell. Suspected side effects can be reported via the MHRA Yellow Card scheme (yellowcard.mhra.gov.uk).

Dietary Changes That May Reduce Sulphur Burps on Ozempic

Dietary modification is often the most effective strategy for reducing sulphur burps in patients taking Ozempic. The primary approach involves identifying and moderating intake of foods high in sulphur-containing compounds, which serve as substrates for bacterial production of hydrogen sulphide gas. However, it is important to maintain nutritional balance, particularly for patients with diabetes who require consistent carbohydrate intake and adequate protein for metabolic health.

Foods that commonly contribute to sulphur burps include:

• Cruciferous vegetables such as broccoli, cauliflower, Brussels sprouts, and cabbage

• Allium vegetables including onions, garlic, leeks, and shallots

• High-protein foods, particularly red meat, eggs, and certain dairy products

• Legumes and pulses, which contain both sulphur compounds and fermentable carbohydrates

• Certain preservatives, particularly sulphites used in dried fruits, wine, and processed foods

Rather than eliminating these foods entirely, patients may benefit from temporarily reducing portions or frequency of consumption whilst their body adjusts to Ozempic, then gradually reintroducing them to identify specific triggers. Keeping a food and symptom diary can help establish patterns and guide personalised dietary adjustments.

Foods that may be better tolerated include:

• Lean proteins such as chicken, turkey, and white fish

• Low-sulphur vegetables including courgettes, carrots, lettuce, and cucumbers

• Whole grains such as oats, brown rice, and quinoa

• Fresh fruits, particularly berries, melon, and citrus

Patients should consider asking for a referral to a registered dietitian with expertise in diabetes management for personalised nutritional guidance. This is particularly important for those struggling to balance symptom management with glycaemic control and nutritional adequacy. NICE guidance on type 2 diabetes management emphasises the importance of individualised dietary advice as part of comprehensive care, and this becomes even more relevant when managing medication side effects that affect eating patterns and food choices.

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