Whether you’re taking Mounjaro for weight loss or diabetes, it has some side effects, although not everybody will get them.
Very common side effects of Mounjaro include:
- diarrhoea
- feeling sick (nausea)
- vomiting (being sick)
- constipation
- low blood sugar (if taken alongside certain diabetes medications)
These side effects are not usually severe and are most likely to happen when you first start taking Mounjaro. Mounjaro is introduced gradually to reduce these side effects, allowing your body to adjust to the treatment. Very common side effects should improve within a few weeks, but speak to your doctor if they persist.
Mounjaro can also cause low blood sugar when used with other medicines for type 2 diabetes, such as insulin. Tell your doctor if you get symptoms of low blood sugar, which include shaking, sweating, dizziness, hunger, and an increased heart rate.
Common side effects of Mounjaro include:
- fast pulse
- mild to moderate allergic reaction, such as eczema, itching, or rash
- pain in the stomach
- constipation
- indigestion
- bloating
- gas and burping
- heartburn or reflux
- fatigue
- an increase in the levels of pancreatic enzymes, which will show up on a blood test
- itching, redness, or irritation at the injection site
- low blood pressure
- dizziness
- hair loss
Uncommon side effects of Mounjaro include:
- gallstones
- an increase in calcitonin (a hormone that helps to control calcium levels)
- weight loss
- injection site pain
- an inflamed pancreas (acute pancreatitis) – speak to your doctor straight away if you notice severe stomach and/or lower back pain that isn’t going away
- low blood sugar (when using Mounjaro alongside metformin)
There may be other side effects that Mounjaro can cause. For an up-to-date list of all side effects, please see your patient information leaflet.
Are there any long-term side effects?
Mounjaro is not known to cause any long-term side effects. If you do get any side effects, they will probably go away or get better within a few weeks or will stop when you stop taking the medicine.
Are there any serious side effects of Mounjaro?
Mounjaro, like other medications, can cause a serious allergic reaction (anaphylaxis). This is a medical emergency and you must call 999 or get to A&E straight away. Symptoms include:
- breathing difficulties
- throat, face and mouth swelling
- fainting
Mounjaro can also cause an inflamed pancreas, known as acute pancreatitis. It might also cause gastroparesis, or dangerously low blood sugars in overdose. These require urgent medical attention, so speak to your doctor or call 111 or 999 if you have intense and persistent stomach and back pain, or if you think you may have used too much.
How to manage the side effects of Mounjaro
To manage the side effects of Mounjaro, you can:
- take your treatment at the same time and day each week
- manage nausea symptoms by sipping cold water, avoiding greasy, heavy meals, and eating smaller meals more often
- make sure to eat enough fibre
- stay hydrated
- take anti-diarrhoea tablets if needed
- only take the dose prescribed to you and avoid increasing your dose unless your doctor tells you to
- let your doctor know if you have any side effects that bother you or aren’t going away on their own
- speak to your doctor if you take other medications that may interact with Mounjaro or cause side effects