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Mounjaro Side Effects

Common Mounjaro side effects include digestive distress, such as vomiting, diarrhea, constipation and nausea. More severe side effects of Mounjaro include acute organ failure, pancreatitis, diabetic retinopathy and gastroparesis. Animal studies show an increased risk of certain thyroid cancers.

Last Modified: February 7, 2024
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Is Mounjaro Safe To Take?

Mounjaro is safe for most patients taking it for the treatment of Type 2 diabetes. The FDA approved it for this purpose, indicating that the benefits of use outweigh the potential risks. Risks may increase when doctors prescribe Mounjaro for off-label use.

Mounjaro risks include several common side effects, such as gastrointestinal upset, and more severe side effects such as allergic reactions. Additionally, animal testing showed an increased risk of a specific type of thyroid cancer. Therefore, the product’s Boxed Warning indicates that patients with a family or personal history of medullary thyroid cancer or those with multiple endocrine neoplasia syndrome Type 2 should not use Mounjaro.

“In both sexes of rats, tirzepatide caused a dose-dependent and treatment-duration-dependent increase in the incidence of thyroid C-cell tumors (adenomas and carcinomas) in a 2-year study at clinically relevant plasma exposures. It is unknown whether Mounjaro causes thyroid C-cell tumors, including medullary thyroid carcinoma (MTC), in humans…” — Boxed Warning for Mounjaro

Patients should discuss the possibility of side effects and adverse reactions with a doctor before taking Mounjaro. Additionally, patients should notify the prescribing doctor if they experience any side effects once beginning tirzepatide treatment.

What Are the Common Side Effects of Mounjaro?

Common Mounjaro side effects are typically gastrointestinal in nature. More than 5% of individuals taking tirzepatide experience digestive issues such as nausea, vomiting, constipation and diarrhea. Some patients also experience abdominal pain and discomfort or generalized body aches.

Common Mounjaro Side Effects
  • Abdominal pain or discomfort
  • Constipation
  • Decreased appetite
  • Diarrhea
  • Nausea
  • Vomiting

Decreased appetite is another symptom reported in many patients taking Mounjaro. This may be the result of delayed gastric emptying, which can extend how long patients feel full after meals.

How Long Do Mounjaro Side Effects Last?

Most side effects of taking Mounjaro resolve within several days. Patients are most likely to experience side effects when first starting Mounjaro and after dosage increases. Higher doses contribute to greater chances of side effects and more severe symptoms.

Some patients reported several Mounjaro long-term side effects, including vomiting that lasted for weeks despite treatment. Anyone experiencing side effects lasting longer than a few days should speak to their doctor to discuss treatment options. Prolonged gastrointestinal issues can result in dehydration and other potentially serious conditions.

Serious Mounjaro Side Effects

Mounjaro can also cause more serious side effects, including acute organ failure, low blood sugar, inflammation of the pancreas, diabetic retinopathy and stomach paralysis. Any of these conditions can be potentially life-threatening. Patients experiencing symptoms such as persistent or severe abdominal pain, vision changes, dizziness or excessive fatigue should report their symptoms to a doctor immediately.

Serious Mounjaro Side Effects
  • Acute gallbladder disease
  • Acute kidney injury
  • Hypoglycemia
  • Gastroparesis
  • Pancreatitis
  • Vision changes

Hypersensitivity to tirzepatide is possible. Therefore, patients with a history of hypersensitivity to GLP-1 agonists should not use Mounjaro. Serious adverse reactions including anaphylaxis can result.

Persistent stomach pain lasting more than a week could be a sign of pancreatitis, a known serious Mounjaro side effect. Severe vomiting that does not respond to conventional treatments may accompany abdominal pain. Patients experiencing these or similar symptoms should report them to a doctor.

Acute Gallbladder Disease

A small percentage of patients taking Mounjaro experience acute gallbladder disease. Conditions reported include cholelithiasis, biliary colic and cholecystectomy. Common symptoms include nausea, vomiting and severe pain in the upper-right abdominal area.

Patients displaying symptoms of gallbladder disease should notify a doctor immediately. Diagnostic testing can confirm the disorder so the doctor can prescribe an appropriate treatment.

Acute Kidney Injury

Dehydration caused by gastrointestinal distress can contribute to dehydration, which in turn may cause acute kidney injury in patients taking Mounjaro. Symptoms of kidney injury include fluid retention, decreased urine production, nausea, fatigue and confusion.

Most cases of kidney injuries from Mounjaro occur in patients with previous renal disorders. However, patients with no history of kidney disease have also reported problems. Treatment with dialysis is sometimes necessary.

Diabetic Retinopathy

Patients with a history of diabetic retinopathy may experience worsening symptoms when taking Mounjaro. Diabetic retinopathy is a serious eye condition affecting people with Type 1 or Type 2 diabetes. Damage to the blood vessels in the retina results in symptoms including blurry vision and floaters.

Patients may not experience symptoms during the early stages of diabetic retinopathy. Severe cases can result in a complete loss of vision. Anyone with a history of diabetic retinopathy should undergo continued monitoring while taking Mounjaro. Treatment cannot reverse the damage, but it can stop the condition from getting worse.


Gastroparesis, sometimes called stomach paralysis, results in food moving very slowly from the stomach to the small intestines. In extreme cases, food may not leave the stomach at all. Symptoms of gastroparesis include unexpected weight loss, feeling full well after eating, vomiting, abdominal pain and bloating.

Patients may see significant weight loss with Mounjaro due to delayed gastric emptying. However, if food passes too slowly through the stomach, it can lead to a near-paralysis. Since food is no longer passing through the digestive tract, patients with gastroparesis may suffer from dehydration or malnutrition.

Several Mounjaro lawsuits claim maker Eli Lilly failed to properly notify patients about the possible risks associated with taking the tirzepatide, including gastroparesis and persistent vomiting. Gastroparesis is also a side effect of Ozempic, another Type 2 diabetes drug that is also often prescribed off-label for weight loss. Drugmaker Novo Nordisk is an additional defendant in the Mounjaro lawsuits.


Patients taking GLP-1 receptor agonists, including Mounjaro, may develop acute pancreatitis. This rapid inflammation of the pancreas can cause severe abdominal pain, persistent vomiting and diarrhea. Anyone displaying these symptoms while taking Mounjaro should seek immediate medical attention.

Careful observation for symptoms of pancreatitis can result in an early diagnosis and the start of treatment. Acute pancreatitis usually resolves within a few days. However, it can cause extreme pain and dehydration. Treatment options include rest, pain medication and IV fluids for dehydration along with stopping Mounjaro.

How To Manage Mounjaro Side Effects

Patients can use traditional methods of reducing gastrointestinal discomfort to manage the side effects of Mounjaro. These include limiting fatty and spicy foods, eating small portions slowly and stopping eating when full.

3 Tips for Managing Side Effects
  1. Eat meals of bland, low-fat foods
  2. Eat small portions
  3. Drink plenty of fluids

Sipping calming beverages, such as chamomile tea and ginger ale, and taking over-the-counter medications may also help reduce nausea and vomiting. Eating high-fiber foods and drinking plenty of fluids can help relieve constipation.

When To Talk to Your Doctor About Mounjaro Side Effects

Patients should talk to a doctor if they experience Mounjaro side effects that last more than a few days or interfere with daily activities. Seek immediate medical attention for serious adverse reactions or medical emergencies related to taking Mounjaro, such as severe abdominal pain, difficulty breathing, swelling in the face and throat, skin rash and vomiting.

While many patients experience minor side effects, especially when first starting the medication or after a Mounjaro dose increase, these usually resolve within a few days. Some Mounjaro side effects such as vomiting and diarrhea can contribute to dehydration, which can lead to serious medical complications. It is important to discuss any symptoms that last for more than a week with a doctor.

Please seek the advice of a medical professional before making health care decisions.