Key takeaways

  • Mounjaro (tirzepatide) is a prescription medication that is used to manage blood sugar levels in adults and certain children with type 2 diabetes.
  • It comes as a liquid in single-dose vials or prefilled pens for weekly injections under the skin.
  • Common side effects of Mounjaro include nausea, diarrhea, and decreased appetite. Serious side effects are also possible, including pancreatitis and gallbladder problems.
  • Mounjaro is not a weight loss drug. But some people using Mounjaro may lose weight.

Mounjaro is a brand-name medication used to improve blood sugar control in adults and children ages 10 years and older with type 2 diabetes. It is typically prescribed as part of a treatment plan that includes a healthy, reduced-calorie diet and regular exercise.

Mounjaro comes as a liquid in prefilled, single-dose pens for weekly injections under the skin.

The active ingredient in Mounjaro is a drug called tirzepatide. It belongs to a group of drugs called called GIP and GLP-1 receptor agonists. At this time, there is no generic version of Mounjaro available.

Note: Mounjaro is not approved by the Food and Drug Administration (FDA) for use as a weight loss drug. But because it is prescribed along with exercise and a balanced diet, some people may lose weight during their Mounjaro treatment.

Mounjaro helps lower and manage blood sugar by:

  • helping your body release more insulin from your pancreas
  • slowing sugar production in your liver
  • slowing the emptying of food from your stomach, which can make you feel full longer

Mounjaro is available in several strengths, ranging from 2.5 milligrams (mg) per 0.5 milliliters (mL) to 15 mg/0.5 mL.

You’ll inject Mounjaro once per week. Your doctor will likely have you start treatment with a 2.5-mg dose of Mounjaro. After 4 weeks of treatment, they’ll increase your dose to 5 mg per week. Starting with a lower dose helps your body get used to the medication.

If your current dose of Mounjaro isn’t managing your blood sugar well enough, your doctor may increase your dose even more. This will be done after another period of 4 weeks, and in increments of 2.5 mg, if needed.

For adults, 15 mg per week is the maximum dosage. For children ages 10 years and older, the maximum dosage is 10 mg. Mounjaro is not approved for children younger than 10 years old.

Your doctor will explain how to use Mounjaro. They’ll also explain how much to inject, how often, and the best time of day to inject it. Be sure to follow your doctor’s instructions.

Injecting Mounjaro

Mounjaro can be injected under the skin of your abdomen, thigh, or back of your upper arm. (If you want the drug injected into your upper arm, you’ll need someone else to give you the injection.) You should rotate the areas where you inject the drug to help prevent skin irritation at the injection site.

Before you start your Mounjaro treatment, your doctor or pharmacist can show you how to inject the drug. For step-by-step instructions or a video on how to use Mounjaro, see the drug manufacturer’s website.

Common side effects

The most common side effects of Mounjaro reported in clinical trials of the drug required by the Food and Drug Administration (FDA) were:

  • nausea
  • diarrhea
  • decreased appetite
  • vomiting
  • constipation
  • indigestion
  • abdominal pain

These side effects, which occurred in at least 5% of people treated with Mounjaro in the studies, were typically mild and manageable.

Mild side effects of Mounjaro may go away within a few days to a couple of weeks. But if they persist or become bothersome, talk with your doctor or pharmacist.

Serious side effects

Serious side effects of Mounjaro can occur, but they aren’t common. Serious Mounjaro side effects that have been reported include:

If you experience serious side effects from Mounjaro, call your doctor right away. But if you think you’re having a medical emergency, immediately call 911 or your local emergency number.

Mounjaro has a boxed warning about the risk of thyroid cancer. This is the most serious warning from the Food and Drug Administration (FDA). It alerts doctors and patients about drug effects that may be dangerous.

Using Mounjaro may raise the risk of developing thyroid cancer. In studies, animals given Mounjaro had an increased risk of thyroid cancer. But it’s not known whether Mounjaro could cause thyroid cancer, specifically medullary thyroid cancer (MTC), in humans.

If you or a family member has a history of MTC or if you have multiple endocrine neoplasia syndrome type 2 (MEN 2), tell your doctor before using Mounjaro. Due to the associated risks, they’ll likely recommend a different treatment option for you.

During your Mounjaro treatment, you should watch for symptoms of thyroid cancer, including:

  • a lump or swelling in your neck
  • difficulty swallowing
  • difficulty breathing
  • hoarseness

Your doctor may also recommend that you have certain blood tests or ultrasounds (a type of imaging test) done to check your thyroid throughout your treatment.

If you have questions about the risk of thyroid cancer with Mounjaro, talk with your doctor or pharmacist.

Whether you have health insurance or not, cost may be a factor when you’re considering Mounjaro. What you’ll pay for Mounjaro may depend on several things, such as your treatment plan and the pharmacy you choose.

Here are a few things to consider regarding Mounjaro cost:

  • Comparing pharmacies: The price of Mounjaro may vary depending on which pharmacy you use, so it can help to compare prices across pharmacies to find the lowest cost.
  • Drug coupons: You may be able to find drug coupons on prescription discount websites that can reduce the cost of your medication. These coupons cannot be used with insurance copays or benefits, but the discounted price may be lower than what you would pay through insurance.
  • Financial assistance: Some websites provide details about drug assistance programs, ways to make the most of your insurance coverage, and links to savings cards and other services. Two such websites are:

Also, a Mounjaro Savings Card is available from the drug manufacturer.

»MORE:

Optum Now is operated by RVO Health. By clicking on this link, we may receive a commission. Learn more.

Here are answers to frequently asked questions about Mounjaro.

Tiredness and fatigue have not been reported as side effects of Mounjaro in clinical studies of the drug.

But it’s possible for tiredness to be a symptom of Mounjaro’s side effects, such as low blood sugar or severe digestive side effects. Fatigue can also be a symptom of type 2 diabetes, for which Mounjaro is used to treat.

If you feel tired after starting Mounjaro treatment, talk with your doctor about possible causes and ways to help reduce your fatigue.

It’s possible. For example, nausea, diarrhea, or constipation might last for a few days or weeks after you start Mounjaro.

Uncommon but serious side effects like pancreatitis or severe digestive problems may persist and lead to kidney damage over time.

If you have questions or concerns about long-term side effects of Mounjaro, talk with your doctor or pharmacist.

Mounjaro is not FDA approved for use as a weight loss drug.

But because Mounjaro is prescribed along with exercise and a balanced diet, some people may lose weight during their treatment with the drug.

Some people using Mounjaro in clinical studies of the drug reported weight loss. Mounjaro slows down your digestion, which can help you feel full for a longer time and thereby decrease your appetite. Also, Mounjaro may help with weight loss by improving your body’s response to insulin.

If you have questions about weight loss with Mounjaro, talk with your doctor.

Taking medications, vaccines, foods, and other things with a certain drug can affect how the drug works. These effects are called interactions.

Certain interactions may cause Mounjaro to be less or more potent than intended or result in unexpected side effects.

Before starting Mounjaro, be sure to tell your doctor about all medications you take, including prescription and over-the-counter types.

Also tell your doctor about your alcohol consumption and any vitamins, herbs, or supplements you take. This can help prevent Mounjaro interactions that may affect your treatment.

Mounjaro may not be right for you if you have certain medical conditions. These are known as drug-condition interactions. Other factors may also affect whether Mounjaro is a good treatment option for you.

Talk with your doctor about your health history before you use Mounjaro. Factors to consider include:

Do not inject more Mounjaro than your doctor prescribes, as this can lead to serious side effects.

Call your doctor if you think you’ve injected too much Mounjaro. You can also call 800-222-1222 to reach America’s Poison Centers or use its online resource. But if you have severe symptoms, immediately call 911 or your local emergency number. Or go to the nearest emergency room.

Mounjaro (tirzepatide) is prescribed to manage blood sugar levels in adults and certain children with type 2 diabetes. It comes as a liquid in single-dose vials or prefilled pens for weekly injections under the skin.

Mounjaro is not FDA approved for use as a weight loss drug. But because Mounjaro improves your body’s response to insulin and is prescribed along with exercise and a balanced diet, some people may lose weight during their treatment with the drug.

Note: This is a summary article about Mounjaro. For more details about this drug, see Mounjaro’s prescribing information or talk with your doctor or pharmacist.

Disclaimer: Healthline has made every effort to make certain that all information is factually correct, comprehensive, and up to date. However, this article should not be used as a substitute for the knowledge and expertise of a licensed healthcare professional. You should always consult your doctor or another healthcare professional before taking any medication. The drug information contained herein is subject to change and is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. The absence of warnings or other information for a given drug does not indicate that the drug or drug combination is safe, effective, or appropriate for all patients or all specific uses.