Both Mounjaro and Wegovy are highly effective for weight loss in adults with overweight or obesity. As with all GLP-1–based treatments, gastrointestinal side effects such as nausea, vomiting, diarrhoea, constipation, and bloating are common, particularly in the early stages of treatment.
Wegovy Side effects are generally mild to moderate and often improve over time. Some people may experience certain symptoms more with Wegovy than Mounjaro, but individual experiences vary.
The strategies below can help manage these effects, whichever treatment you use.
Common Side Effects and How to Manage Them
Not everyone will experience side effects and those who do, usually find they are mild and only last a few weeks. It can make sticking to your weight loss journey a bit more difficult, but you’ll be surprised that small nutrition and lifestyle strategies can make a significant impact.
Most people will manage to cope with side effects well, greatly improving their overall experience of their treatment.
1. Nausea
Nausea is one of the most common side effects of Wegovy with around 44.2% of participants on the 2.4 mg weekly dose reported nausea (1). Nausea can occur at the onset of starting Wegovy or after an increase in dosage.
It happens due to the way Wegovy works which is by slowing down the rate your stomach digests food. This is great as it helps aid weight loss by promoting a feeling of fullness so you may eat less however it can also make some people feel queasy or uncomfortable. This is a normal reaction from your body adjusting to the medication.
Tips to ease nausea:
• Eat smaller meals, frequently throughout the day
• Try our Bland Diet Guide temporarily (rice, porridge, carrots, applesauce, toast)
• Sip water, ginger or peppermint tea
• Eat slowly and remain upright for 30–60 minutes after meals to help reduce reflux and ease digestion
• Cold foods may be easier to tolerate
• Avoid spicy, high fat, or overly sweet foods
2. Vomiting
Vomiting is an unfortunate potential side effect of Wegovy. As with Nausea, this side effect is a result of your body adjusting to the medication and does not mean the medication is unsafe or not working.
Tips to manage vomiting:
• Stay well hydrated with small sips of water, squash or clear broth throughout the day, or try an oral rehydration solution
• Gradually reintroduce soft, bland foods (plain pasta, bananas, toast, porridge, well cooked vegetables, low-fat cheese). If vomiting is persistent, then try an oral rehydration solution.
• Avoid spicy, high fat, or overly sweet foods
3. Diarrhoea
Some people notice looser stools or diarrhoea when taking Wegovy. It's usually short-lived as your body and digestive system adapt to the medication. It can be unpleasant but there are some things you could try to help reduce the occurrence:
Tips to manage diarrhoea:
• Stay hydrated throughout the day with small sips of water or sugar-free squash
• Eat small, frequent meals and snacks which is easier to digest.
• Temporarily choose low-fibre foods (white bread, plain biscuits, white pasta or rice, low-fibre cereals)
• Avoid spicy, high fat, or overly sweet foods
4. Constipation
This is also a common side effect because of the slower rate of digestion as a result of the medication. This can make your stools less frequent or firmer and harder to pass.
Tips to manage constipation:
• Gradually increase fibre intake (oats, beans, lentils, fruit, vegetables, wholegrains)
• Make sure you are drinking 2–3 litres of water daily
• Include gentle movement, such as walking (even 10-15 minutes after a meal can make a huge difference)
• Seek advice from Morrisons Clinic about suitable stool softeners or laxatives if needed
5. Abdominal Discomfort / Bloating
When digestion is slower, it can produce more gas, or just make you feel unusually full or stretched in the abdomen. It is normally nothing to worry about and thankfully there are ways to help reduce the uncomfortable feeling:
Tips to ease discomfort and bloating:
• Eat slowly and chew food thoroughly
• Reduce carbonated drinks and chewing gum (these can make it worse for some people)
• Eat smaller, more frequent meals and snacks to reduce the pressure on your stomach
• Avoid personal trigger foods
6. Indigestion / Reflux
Tips to manage reflux:
• Eat smaller, frequent meals to alleviate discomfort
• Avoid lying down immediately after eating
• Limit spicy, acidic, or high-fat foods, as well as caffeinated foods and drinks
Key Takeaways
Gastrointestinal side effects such as nausea, vomiting, constipation and diarrhoea are all common, especially in the early stages, but are usually mild and temporary, settling in a few weeks for most people.
Nutritional strategies as above, portion adjustments, and gentle lifestyle changes can make side effects more manageable.
The key is that these symptoms can be managed effectively, helping you stay on track with your treatment and your weight management goals.
If your symptoms ever feel unmanageable, we’re here to help at Morrisons Clinic.
References
- Wilding, J. P. H., Batterham, R. L., Calanna, S., Davies, M., Van Gaal, L. F., Lingvay, I., McGowan, B. M., Rosenstock, J., Tran, M. T. D., Wadden, T. A., Wharton, S., Yokote, K., Zeuthen, N., Kushner, R. F., & STEP 1 Study Group (2021). Once-Weekly Semaglutide in Adults with Overweight or Obesity. The New England journal of medicine, 384(11), 989–1002. https://doi.org/10.1056/NEJMoa2032183
