Mounjaro is the brand name for the medication known as ‘tirzepatide’. This drug is a GLP-1 type medication and is used as a treatment to support weight loss for people with overweight or obesity. As with any type of medication, there are a number of potential side effects that are associated with taking Mounjaro. Although these will vary greatly between individuals, it can be helpful to be aware of any side effects you may experience and what to do about them before starting treatment.
Side effects of the digestive system
The most common side effects of Mounjaro are associated with the digestive system, affecting just over half of the people taking it for weight loss in studies. These typically occur within the first few weeks of starting the medication or following an increase in dose, and include:
- Nausea – affecting 25-30% of people
- Diarrhoea – around 20% of people
- Other digestive system effects such as abdominal pain, vomiting and constipation
These side effects were described by those in the trials as mild to moderate in severity, and 2-4% of people taking Mounjaro stopped due to side effects affecting the digestive system.
Many of these side effects can be minimised or avoided by working with your clinical team to find the right dose for you and taking a proactive approach to hydration and nutrition, whilst occasionally using medication to offset side effects while your body adapts.
Hair loss
Hair loss was reported by up to 5% of those taking Mounjaro for weight loss in trials; it was mostly of mild severity and resolved without needing to discontinue the medication.
Other side effects
Other common side effects reported when taking Mounjaro include:
- Fatigue
- Dizziness
- Episodes of low blood pressure
- Skin reactions at the injection site (such as redness or itching)
Of note, this medication can cause low blood sugar in those who have type 2 diabetes and are also taking other diabetic medications.
Skin and facial changes
Weight loss medications and rapid weight loss are also associated with the development of excess skin or skin sagging, which occurs due to the loss of fat underneath the skin, causing the skin to lose some of its volume and elasticity. This effect can be more pronounced on the face for some individuals, resulting in an altered appearance of facial features, commonly referred to online as ‘Ozempic face’. If this is something that is of concern, it is worth speaking with your healthcare team for advice on how these effects can be managed or minimised.
Nutrition
Although not strictly a side effect of the medication itself, weight loss with medications like Mounjaro can sometimes lead to nutritional deficiencies. Individuals tend to be eating significantly less when taking these treatments, and it is important to ensure that they are still getting all the essential nutrition the body needs to work properly. Support from an experienced dietician can help to minimise any nutritional deficiencies that may arise as a result of taking Mounjaro.
Key messages
- Mounjaro can commonly cause mild to moderate side effects affecting the digestive system, such as nausea and diarrhoea
- Some people experience hair loss when taking Mounjaro, but this typically resolves on its own without needing to stop the medication
- Significant and rapid weight loss can lead to loss of skin volume on the body and face
- A dietitian's input can help reduce the risk of dietary deficiencies while taking weight loss medications
What our clinical experts say
GLP1s should be used to gain control of appetite rather than necessarily ‘suppressing’ it. With too high doses, there is a real risk of under-nutrition leading to the loss of muscle, bone and skin health. Staying hydrated, focusing on nutrition, adding in strength training and going low and slow with medication can mitigate many of the side effects experienced when patients use GLP-1s with adequate medical and nutritional support.
Dr Caroline Butler
Genwell reflections
Whilst all medications come with potential side effects, the experienced team at Genwell are here to answer any questions you may have both prior to starting and during treatment. Our team of clinical experts are here to make your weight loss journey work for you. With up-to-date and clear information, Genwell can help you weigh up the benefits and side effects of treatment and work with you to create a tailored plan for you.