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Side Effects of Mounjaro

Side Effects of Mounjaro

Rajive Patel NowPatientGreen tick
Updated on 28 Dec 2023

Introduction to Mounjaro

Mounjaro is the first and only approved once-weekly GIP (glucose-dependent insulinotropic polypeptide) and GLP-1 receptor agonist. It is a single molecule that targets the body’s receptors for GIP and GLP-1, which are natural incretin hormones.

Mounjaro is manufactured by the pharmaceutical company Eli Lilly Mounjaro. It was first approved by the Food and Drug Administration (FDA) in 2022. It is also known by its active ingredient tirzepatide, which is an injectable medicine used to improve blood sugar (glucose) levels in adults with type 2 diabetes mellitus. It is not intended for use in people with type 1 diabetes or those who have had pancreatitis. Mounjaro is a once-weekly injectable subcutaneous medication that comes in a single-dose pen.

How Mounjaro works

Mounjaro works by activating two different receptors in the body: the glucose-dependent insulinotropic polypeptide (GIP) receptors and the glucagon-like peptide-1 (GLP-1) receptors. These receptors are responsible for regulating blood glucose levels. By activating these receptors, Mounjaro helps the pancreas produce more insulin, reduces the liver’s production of sugar, and slows down the movement of food through the digestive system, leading to a feeling of fullness.

Administration and dosage

Selecting the injection site

Before administering Mounjaro, it is important to select an appropriate injection site. The recommended injection sites include the thigh, abdomen, or upper arm. A tirzepatide injection is given subcutaneously and you should rotate the injection site with each dose to avoid injecting in the same spot repeatedly. It is advised to keep a distance of at least 1 inch between injection sites.

Preparing the Mounjaro pen

To prepare the Mounjaro pen for injection, follow these steps:

  1. Wash your hands thoroughly with soap and water
  2. Remove the Mounjaro pen from the refrigerator and allow it to reach room temperature for approximately 30 minutes
  3. Check the pen to ensure that the medicine is not frozen, cloudy, discolored, or contains any particles. If you notice any abnormalities, do not use the pen and contact your healthcare provider
  4. Remove the cap from the pen and do not touch the needle

Administering the injection

To administer the Mounjaro injection, follow these steps:

  1. Choose the injection site as discussed earlier
  2. Cleanse the injection site with an alcohol swab and allow it to dry
  3. Hold the pen with the needle pointing upwards and tap the pen gently to remove any air bubbles
  4. Prime the pen by turning the dose selector until the dose window shows “0.5” and a drop of insulin appears at the needle tip
  5. Insert the needle into the cleansed injection site at a 90-degree angle and press the injection button on the pen to deliver the dose
  6. Hold the pen in place for a few seconds to ensure that the full dose has been administered
  7. Remove the needle from the injection site and apply gentle pressure with a cotton ball or tissue

Storage and disposal of Mounjaro

Mounjaro should be stored in the refrigerator between 36°F to 46°F (2°C to 8°C). It is important to keep the pens in their original packaging to protect them from light. Do not freeze the Mounjaro pens. If needed, the pen can be stored at room temperature (up to 86°F or 30°C) for up to 21 days, but it should be kept away from direct heat and sunlight. It is crucial to always check the pen before using it to ensure that it is not frozen. If the pen is dropped on a hard surface, do not use it and use a new pen for your injection.

After administering a dose of Mounjaro, it is important to dispose of the used pen safely. Place the used pen in an FDA-cleared sharps disposal container immediately after use. Do not throw away the pen in the household trash. If you do not have an FDA-approved sharps container, you can use a heavy-duty plastic container with a puncture-resistant lid. Label the container properly to indicate that it contains hazardous waste, and keep it out of the reach of children. Do not recycle the used sharps container.

Potential side effects of Mounjaro

As with any medication, Mounjaro may cause side effects. The most common side effects of Mounjaro reported by patients are gastrointestinal symptoms that include indigestion, nausea, diarrhea, decreased appetite, vomiting, constipation, dyspepsia, and abdominal pain. These side effects are usually mild and may improve over time. However, if you experience severe or persistent side effects, it is important to contact your healthcare provider.

In rare cases, Mounjaro may cause more serious side effects. These can include serious allergic reaction, pancreatitis, severe stomach problems such as gastroparesis, gallbladder problems, low blood sugar (hypoglycemia), diabetic retinopathy and kidney problems. If you experience any of these symptoms, seek immediate medical attention.

To learn about side effects, talk with your doctor or pharmacist, or read Mounjaro’s prescribing information.

Boxed warning

A boxed warning is the most serious warning from the Food and Drug Administration (FDA). Mounjaro has a boxed warning for the risk of medullary thyroid carcinoma (MTC) (thyroid cancer/ thyroid tumors) and Multiple Endocrine Neoplasia syndrome type 2 (MEN 2).

Using Mounjaro may increase your risk of developing thyroid cancer and MEN 2. Due to this risk, your doctor will likely not prescribe this drug if there is a family history of thyroid cancer or MEN 2.

Lifestyle tips for managing type 2 diabetes

In addition to using Mounjaro, making positive lifestyle changes can greatly benefit individuals with type 2 diabetes. Here are some lifestyle tips to consider:

At home tips

  • Follow a well-balanced diet that includes a variety of fruits, vegetables, whole grains, lean proteins, and healthy fats
  • Limit your intake of sugary and processed foods
  • Engage in regular physical activity, such as walking, cycling, or swimming
  • Monitor your blood sugar levels regularly and keep a record of your readings
  • Take prescribed medications, including Mounjaro, as directed by your healthcare provider

Away-from-home tips

  • Plan your meals and snacks ahead of time to make healthier choices when eating out
  • Opt for grilled or baked options instead of fried foods
  • Choose water or unsweetened beverages instead of sugary drinks
  • Be mindful of portion sizes and avoid overeating

Continuing success

  • Stay motivated by setting realistic goals and celebrating your achievements
  • Seek support from friends, family, or a support group
  • Practice stress management techniques, such as deep breathing exercises or meditation
  • Keep up with regular check-ups and appointments with your healthcare provider

Maintaining an active lifestyle

  • Incorporate physical activity into your daily routine, such as taking the stairs instead of the elevator or going for a walk during your lunch break
  • Explore different types of exercise to find activities that you enjoy, such as dancing, yoga, or strength training
  • Aim for at least 150 minutes of moderate-intensity aerobic activity per week, along with muscle-strengthening exercises at least twice a week

Mounjaro for weight loss

While Mounjaro is primarily used as a diabetes treatment in individuals with type 2 diabetes, clinical trials have shown promising results for obesity. In a 72-week clinical trial, patients who received a 15 mg dose of Mounjaro experienced a mean body weight loss of 20.9% compared to 3.1% in the placebo group. However, it is important to note that Mounjaro has not yet been approved by the FDA for weight loss purposes.

Mounjaro savings and resources

Managing diabetes can be costly, but there are resources available to help offset the expenses. It is recommended to check with your healthcare provider or pharmacist to see if you qualify for any savings programs or discounts. Additionally, Mounjaro’s official website provides valuable resources and information for individuals with type 2 diabetes.

Frequently asked questions about Mounjaro

Q: How does Mounjaro compare to other diabetes medications?

A: Mounjaro belongs to a class of medications called incretin mimetics, which work by activating certain receptors in the body to regulate blood sugar levels. It is similar to other medications such as Ozempic (semaglutide), Trulicity, and Victoza. However, each medication may have slight differences in terms of dosing, possible side effects, and efficacy. It is best to consult with your healthcare provider to determine which medication is most suitable for you.

Q: Can Mounjaro be used alongside other diabetes medications?

A: Mounjaro can be used in combination with other diabetes medications, such as metformin or insulin, to help manage blood sugar levels. However, it is important to consult with your healthcare provider to ensure that there are no potential drug interactions or contraindications. Always inform your healthcare provider of any medical conditions and prescription drugs or over-the-counter drugs including supplements you are taking.

Q: Can you take Mounjaro during pregnancy and breastfeeding?

It’s not known whether Mounjaro is safe to use during pregnancy. Let your doctor know if you’re pregnant or planning to become pregnant before starting this drug. They will provide medical advice and may recommend a different treatment option for you.

Q: How long does it take for Mounjaro to start working?

A: The full effects of Mounjaro may take several weeks to be noticeable. It is important to continue taking the medication as prescribed and monitor your blood sugar levels regularly. If you have any concerns or questions about the effectiveness of Mounjaro, consult with your healthcare provider.


Mounjaro is a once-weekly injectable medication that can help individuals with type 2 diabetes manage their blood sugar levels. By following the proper administration techniques, storing and disposing of the medication correctly, and making positive lifestyle changes, individuals can effectively incorporate Mounjaro into their diabetes management plan. It is essential to work closely with a healthcare professional to ensure that Mounjaro is the right medication for your specific needs and to address any questions or concerns you may have. Remember, managing diabetes requires a comprehensive approach that includes medication, a healthy diet, regular exercise, and ongoing medical supervision.


Medical Disclaimer

NowPatient has taken all reasonable steps to ensure that all material is factually accurate, complete, and current. However, the knowledge and experience of a qualified healthcare professional should always be sought after instead of using the information in this page. Before taking any drug, you should always speak to your doctor or another qualified healthcare provider.

The information provided here about medications is subject to change and is not meant to include all uses, precautions, warnings, directions, drug interactions, allergic reactions, or negative effects. The absence of warnings or other information for a particular medication does not imply that the medication or medication combination is appropriate for all patients or for all possible purposes.

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