Side effects Mounjaro
This page has been reviewed by
Dr. Nicolette Lammers.
Side effects Mounjaro
Like all medicines, Mounjaro can cause side effects, although not everybody gets them.
Serious side effects
Occasionally (may affect up to 1 in 100 people treated)
Inflammation of the pancreas (acute pancreatitis), which can cause severe abdominal and back pain that does not subside. You should consult a doctor immediately if you notice such symptoms.
Other side effects
Very common (may affect more than 1 in 10 people treated)
- Nausea
- Diarrhea
– These side effects are not usually serious. They occur most frequently at the beginning of treatment with tirzepatide, but decrease over time in most patients.
Low blood sugar (hypoglycemia) is very common when tirzepatide is used together with medicines containing a sulfonylurea and/or insulin. If you are using a sulphonylurea or insulin, the dose may need to be reduced while you are using tirzepatide.
- Symptoms of low blood sugar can include headaches, drowsiness, weakness, dizziness, feeling hungry, confusion, irritability, rapid heartbeat and sweating. Your doctor should tell you how to treat low blood sugar.
Common (may affect up to 1 in 10 people treated)
- Low blood sugar (hypoglycemia) often occurs when tirzepatide is used in combination with metformin and a sodium-glucose co-transporter 2 (SGLT2) inhibitor (another diabetes medicine).
- Allergic reactions (hypersensitivity) (e.g. skin rash, itching and eczema)
- Feeling less hungry (reduced appetite)
- Stomach (abdominal) pain
- Vomiting – this usually disappears over time
- Digestive disorders (dyspepsia)
- Constipation
- Bloated belly
- Belching (burping)
- Flatulence (bloating)
- Reflux or heartburn (also called gastroesophageal reflux disease – GERD) – a disease caused by stomach acid that passes from the stomach into the esophagus.
- Tiredness (fatigue)
- Reactions at the injection site (e.g. itching or redness)
- Fast pulse
- Elevated levels of pancreatic enzymes (such as lipase and amylase) in the blood
Occasionally (may affect up to 1 in 100 people treated)
- Low blood sugar (hypoglycemia) occasionally occurs when tirzepatide is used in combination with metformin.
- Gallstones
- Weight loss
- Elevated calcitonin levels in the blood
Frequently asked questions (FAQ)
How much does a Mounjaro syringe cost?
Mounjaro is supplied either in the form of a vial (i.e. the injections must be drawn up using a syringe) or a multi-dose prefilled pen (these contain doses for one month). The cost of a Mounjaro injection therefore varies depending on the dosage form, dosage and country.
Patients should enquire about the exact prices at their pharmacy.
How much weight can you lose with Mounjaro?
Depending on the dosage and individual response, significant weight loss can be achieved with Mounjaro. Studies show that patients can lose up to 15-22% of their body weight on average, especially at higher doses and in combination with lifestyle changes. However, actual results vary and should be discussed with a doctor.
Which is better, Ozempic or Mounjaro?
Whether Ozempic or Mounjaro is better depends on the patient's individual needs and health goals. Mounjaro combines GLP-1 and GIP receptor agonists, which may offer stronger effects on blood glucose lowering and weight loss, while Ozempic is a proven GLP-1 receptor agonist. The decision should be made with a healthcare professional based on medical history and desired outcomes.
Mounjaro reduces your appetite and makes you feel full, making it easier to change your lifestyle and give up unhealthy habits. In the best case scenario, you will use Mounjaro to achieve your desired weight and at the same time develop a healthy lifestyle that enables you to maintain your weight without medication.