Introduction: What to Expect with Weight Loss Injections
At Tracey Bell Clinic, we provide medically supervised weight loss injections, including Mounjaro (Tirzepatide) and Wegovy (Semaglutide), to help patients achieve effective, sustainable weight loss. While these medications have transformed weight management for many, some unexpected side effects have been reported—one of the most common being sulphur burps.
Patients also describe experiencing changes in taste, smell, and digestion while on Mounjaro or Wegovy, leading to questions about why these effects occur and how they can be managed.
This article explores these unusual but non-dangerous side effects, what the research tells us about them, and how patients can reduce discomfort while continuing their weight loss journey.
What Are Sulphur Burps?
Sulphur burps are burps that have a strong, unpleasant rotten egg smell. This odour is caused by hydrogen sulphide (H₂S) gas, which is produced when certain foods break down in the digestive system. While burping is a normal bodily function, sulphur burps occur when the digestive process slows down, allowing gas to accumulate and be expelled with a foul smell.
Sulphur burps are often associated with:
Slowed digestion and gastric emptying
Dietary choices that lead to increased fermentation in the gut
Changes in gut bacteria and bile production
Why are sulphur burps more common with weight loss injections like Mounjaro and Wegovy?
Let’s dive into the science behind this unusual side effect.
Why Do Sulphur Burps Occur with Mounjaro & Wegovy?
1. Slowed Digestion & Delayed Gastric Emptying
Both Mounjaro and Wegovy are GLP-1 receptor agonists (Mounjaro also acts on GIP receptors). One of their primary effects is slowing gastric emptying, meaning food stays in the stomach longer than usual.
What happens when digestion slows?
- Food sits in the stomach for an extended period.
- As food breaks down, bacteria in the gut ferment certain proteins and produce hydrogen sulphide gas.
- This gas is released through belching, leading to the characteristic “sulphur burps.”
Why is this more common with Mounjaro than Wegovy?
- Mounjaro has a dual-action mechanism affecting both GLP-1 and GIP receptors, which may slow digestion even more significantly than Wegovy.
- This means food remains in the stomach for longer, allowing more time for fermentation and gas production.
2. Gut Microbiome Changes & Bile Production
Both Mounjaro and Wegovy affect gut bacteria, which play a critical role in digestion and metabolism. Some patients report:
Changes in stool consistency and frequency
Increased bloating and gas
A shift in gut bacteria that affects digestion
Because GLP-1 medications influence bile production, the way fats are broken down and absorbed may change, sometimes leading to foul-smelling gas production.
3. High-Protein & High-Sulphur Foods
Certain foods are more likely to produce sulphur-containing gases when digested. Patients on Mounjaro or Wegovy often adjust their diet to include more protein, which can increase sulphur burps due to the breakdown of sulphur-containing amino acids.
Foods That May Worsen Sulphur Burps:
High-protein foods – Red meat, eggs, poultry, fish
Sulphur-rich vegetables – Broccoli, cabbage, onions, garlic
Dairy products – Cheese, milk, cream
Carbonated drinks – Soda, sparkling water, energy drinks
Alcohol & artificial sweeteners – Some sugar substitutes (sorbitol, xylitol) may increase gut fermentation
Tip: Patients who notice sulphur burps should temporarily reduce high-sulphur foods and monitor whether symptoms improve.
Changes in Taste & Smell with Mounjaro & Wegovy
Many patients report altered taste perception and heightened sensitivity to smells while on weight loss injections.
Common Taste & Smell Changes Reported by Patients:
Metallic or bitter taste in the mouth
Increased sensitivity to strong odours (perfumes, cleaning products, food smells)
Reduced enjoyment of fatty or sugary foods
Why Do These Changes Occur?
- GLP-1 medications affect taste receptors
- Studies suggest that GLP-1 influences taste perception, making certain foods taste stronger, duller, or different.
- Changes in digestion impact bile & stomach acids
- This can alter how foods are broken down and absorbed, leading to differences in taste perception.
- Reduced cravings & food preferences
- Many patients experience a natural aversion to greasy, sugary, or processed foods, helping them adopt healthier eating habits.
Good news: Taste and smell changes usually improve after a few weeks as the body adjusts to the medication.
How to Reduce Sulphur Burps & Taste/Smell Changes on Mounjaro & Wegovy
1. Adjust Your Diet to Reduce Sulphur Burps
Eat smaller, more frequent meals instead of large portions.
Reduce high-sulphur foods like eggs, red meat, and garlic.
Increase fibre intake to support gut health.
Stay hydrated – drink plenty of water to help digestion.
2. Use Digestive Aids to Support Gut Health
Try probiotics or fermented foods (yogurt, kefir) to support gut bacteria.
Consider taking digestive enzymes to help break down proteins and fats more efficiently.
3. Prevent Taste & Smell Changes
Rinse your mouth frequently with water or mild mouthwash.
Switch to bland foods (rice, oats, plain chicken) if strong tastes bother you.
Avoid strong-smelling environments (perfume stores, heavy cooking areas) if odour sensitivity is high.
Patients at Tracey Bell Clinic receive full medical support and dietary guidance to manage side effects while maximising weight loss results.
Final Thoughts: Are These Side Effects a Reason to Stop Taking Mounjaro or Wegovy?
For most patients, sulphur burps, taste changes, and smell sensitivity are temporary and do not require stopping treatment. These effects usually improve over time as the body adjusts to the medication.
However, if symptoms become severe or persist, adjustments in diet, hydration, and medication dosage can help manage discomfort.