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Pronunciation: mown-JAHR-OH
Generic name: tirzepatide
Dosage form: injection, for subcutaneous use (2.5 mg, 5 mg, 7.5 mg, 10 mg, 12.5 mg,15 mg per 0.5 mL in single-dose pen)
Drug class: Incretin mimetics

Medically reviewed by Melisa Puckey, BPharm. Last updated on Jan 10, 2024.

What is Mounjaro?

Mounjaro (tirzepatide) injection is used for type 2 diabetes in adults to lower blood sugar levels (blood glucose) and A1C levels. Mounjaro is a once-weekly injection that should be used with diet and exercise. Clinical trials for a 15 mg dose of Mounjaro (tirzepatide) for weight loss showed patients lost a mean of 20.9% of their body weight compared to 3.1% for placebo over 72 weeks. Zepbound is the name of the weight loss version of Mounjaro, they both contain the same active ingredient (tirzepatide), Mounjaro is FDA-approved for type 2 diabetes and Zepbound is FDA-approved to help with weight loss.

Mounjaro is the first GIP and GLP-1 receptor agonist, which works on the glucose-dependent insulinotropic polypeptide (GIP) receptors and the glucagon-like peptide-1 (GLP-1) receptors.

Mounjaro works to lower blood sugar by helping the pancreas make more insulin, lowering the amount of sugar your liver makes, and slowing the rate food passes through your body, making you feel full longer. It does this by activating the two receptors, GIP and GLP-1, which are natural incretin hormones that help regulate blood sugar levels.

Mounjaro injection became an FDA-approved medicine on May 13, 2022, to improve blood sugar (glucose) levels in adults with type 2 diabetes mellitus when used together with diet and exercise. Mounjaro is not for use in people with type 1 diabetes. It is not known if this medicine can be used in people who have had pancreatitis.

Has the FDA approved Mounjaro for weight loss?

Yes, Mounjaro's active ingredient tirzepatide is approved for weight loss, but it is under the brand name Zepbound. Zepbound has the same active ingredient as Mounjaro, and both are made by Eli Lilly and Company.

The Mounjaro brand is not approved for weight loss by the FDA. Mounjaro is an FDA-approved medicine used to improve blood sugar (glucose) levels in adults with type 2 diabetes mellitus when used together with diet and exercise.

Mounjaro’s active ingredient tirzepatide was used in the Phase 3 SURMOUNT-1 72-week weight loss clinical trials. The mean tirzepatide weight loss was 15% for the 5mg dose, 19.5% for the 10mg dose, 20.9% for the 15mg dose, and 3.1% for placebo. The trial included patients who were overweight, obese, and had a weight-related health issue but excluded patients with diabetes.

What are the side effects of Mounjaro?

Common Mounjaro side effects

The most common Mounjaro side effects include nausea, diarrhea, decreased appetite, vomiting, constipation, dyspepsia, and abdominal pain, which affects 5% or more patients.

Serious Mounjaro side effects

Stop using this medicine and get emergency medical help if you have:

Call your doctor at once if you have:

This is not a complete list of side effects, and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.


Call your doctor immediately if you have thyroid tumor symptoms, such as a lump or swelling in your neck, hoarseness, trouble swallowing, or shortness of breath.

In studies with rats, tirzepatide and medicines that work in the same way caused thyroid tumors, including thyroid cancer. It is not known whether Mounjaro will cause thyroid tumors or a type of thyroid cancer called medullary thyroid carcinoma (MTC) in people.

You should not use this medicine if you or you have a family history of a type of thyroid cancer called medullary thyroid carcinoma (MTC) or if you have an endocrine system condition called Multiple Endocrine Neoplasia syndrome type 2 (MEN 2).

Keep all appointments with your doctor and the laboratory. Your doctor may order certain tests to check your body's response to this medicine.

Before using this medicine

You should not use this medicine if you:

Tell your doctor if you have ever had:


Tell your healthcare provider if you are pregnant, you become pregnant, or plan to become pregnant while using this medicine. It is not known if this medicine will harm your unborn baby.

This medicine can make birth control pills less effective. Ask your doctor about other birth control options such as an injection, implant, skin patch, vaginal ring, condom, diaphragm, cervical cap, or contraceptive sponge. If you take birth control pills, you may need to use additional birth control methods for 4 weeks after starting this medicine, and for 4 weeks each time, the dose is raised.


Tell your healthcare provider if you are breastfeeding or plan to breastfeed while using this medicine. It is not known whether this tirzepatide passes into your breast milk. Talk to your healthcare provider about the best way to feed your baby while using this medicine.

How should I use Mounjaro?

You should follow the directions on your prescription label carefully and ask your pharmacist or doctor to explain any part you do not understand. It is important to use this medicine exactly as directed. Do not take more or less of it or more often than your doctor prescribes.

Mounjaro is a pre-filled pen injected under the skin (subcutaneously).

Mounjaro is usually given:

Your doctor will usually start you on a low dose, which will be gradually increased, but not more than once every 4 weeks.

You may change the day of the week you use this medicine as long as there is at least three days between doses.

You may give insulin in the same area as this medicine, but they should not be given right next to each other. Do not mix insulin and Mounjaro in the same injection.

Mounjaro controls type 2 diabetes but does not cure it. It may take four weeks or longer before you see the full benefit of this medicine. Continue to take this medicine even if you feel well. Do not stop taking this medicine without talking to your doctor.

For more detailed instructions with diagrams, on how to use this medicine, click here: Instructions for Mounjaro.

What is the cost of Mounjaro?

The cost for prescription drugs varies depending on your insurance plan and which pharmacy you use. Refer to our price guide page for more information about the cost of Mounjaro.

You may also be eligible for a Mounjaro savings card or Mounjaro coupon. Ask your doctor or pharmacist if you qualify.

Mounjaro Dosing Information

Usual Adult Dose for Diabetes Type 2:

Initial dose: 2.5 mg under the skin (subcutaneously) once a week.

After 4 weeks: The dosage should be increased to 5 mg subcutaneously once a week.

If additional glycemic control is needed: The dosage should be increased in 2.5 mg increments after at least 4 weeks on the current dose.

Maximum dose: 15 mg subcutaneously once a week.

Comments: The 2.5 mg dosage is for starting of treatment and is not intended for glycemic control. The day of weekly administration can be changed, if necessary, as long as the time between the 2 doses is at least 3 days (72 hours).

What strength are Mounjaro pens available as?

There have been issues with Mounjaro availability with drug shortages for some strengths due to increase for the demand.

What should I do if I miss a dose?

Take the missed dose as soon as you remember it within 4 days after the missed dose. However, if more than 4 days have passed, skip the missed dose and continue your regular dosing schedule. Do not inject two doses within 3 days of each other.

What should I do in case of overdose?

In case of overdose, call the poison control helpline at 1-800-222-1222. Information is also available online at Poison Help If the victim has collapsed, had a seizure, has trouble breathing, or can't be awakened, immediately call emergency services at 911.


Tell your doctor and pharmacist what prescription and nonprescription medications, vitamins, nutritional supplements, and herbal products you are taking or plan to take. Your doctor may need to change the doses of your medications or monitor you carefully for side effects.

Birth control pills may not work as well while receiving this medicine. Your doctor may suggest you use another form of birth control for 4 weeks after starting this medicine and for 4 weeks after each dose change.

Taking tirzepatide with other medicines to treat diabetes like insulin or sulfonylureas may increase your risk of hypoglycemia. Talk to your doctor and pharmacist about low blood sugar and how to manage it.

This list is not complete. Many other drugs may interact with this medicine, including prescription and over-the-counter medicines, vitamins, and herbal products. To check for interactions with this medicine click the link below.



Active ingredient: tirzepatide

Inactive ingredients: sodium chloride, sodium phosphate dibasic heptahydrate, and water for injection. Hydrochloric acid solution and/or sodium hydroxide solution may have been added to adjust the pH.


Eli Lilly and Company.

Marketed by: Lilly USA, LLC Indianapolis, IN 46285, USA.

Popular FAQ

Mounjaro and Ozempic are prescription medicines used alongside diet and exercise to help control blood sugar (glucose) levels in adults with type 2 diabetes. Ozempic is also approved to lower the risk of a major cardiovascular event (like a heart attack or stroke) in patients with type 2 diabetes. Mounjaro has not yet received this indication, although studies are ongoing. Continue reading

Ozempic, Mounjaro, Wegovy and Zepbound can all lead to long-term weight loss, but only Wegovy and Zepbound are approved by the FDA for this use. In studies, Zepbound has led to a 21% weight loss in adults using the highest dose, while Wegovy has led to about a 15% weight loss. Continue reading

Mounjaro (generic name: tirzepatide) will start to lower your blood sugar levels right away but it can take 8 to 12 weeks to reach your target A1C goal. When compared to some other diabetes treatments, studies have shown that it can take 8 weeks to reach an A1C target of ≤7% and 12 weeks to reach an A1C ≤6.5% with Mounjaro. Significant weight loss can occur as early as 28-weeks. Continue reading

There’s no evidence that hair loss is a direct side effect of Ozempic, Wegovy, Mounjaro or Zepbound. Hair loss is more likely due to the stress of rapid weight loss on your body, which can lead to temporary shedding of hair over several months, a condition known as telogen effluvium. Continue reading

Your insurance coverage for Mounjaro will vary based upon your insurance plan and drug benefits. The manufacturer of Mounjaro offers a savings card that can lower your cost to $25 for up to a 3-month supply, if you have commercial prescription insurance. Patients covered under government insurance such as Medicare or Medicaid do not qualify for the $25 savings card. Continue reading

Mounjaro's active ingredient has been shown to help with weight loss when used to treat obese patients. Mounjaro's active ingredient tirzepatide is approved for weight loss but under the brand name Zepbound, in studies participants treated with Mounjaro's active ingredient tirzepatide lost between 16.1 kg (35.5 lb) and 23.6 kg (52.0 lb) on average over 72 weeks. Continue reading

Your Mounjaro single dose pen or vial can be stored unrefrigerated for up to 21 days, not to exceed a room temperature of 86ºF (30ºC). Otherwise, store it in the refrigerator at 36°F to 46°F (2°C to 8°C). Always keep Mounjaro in its original carton to protect it from light.
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Mounjaro (generic name: tirzepatide) does not cause fatigue, which can leave you feeling tired, weak and with low energy. However, fatigue can be a common side effect associated with type 2 diabetes. Talk to your doctor if your symptoms of fatigue continue or are severe. Continue reading

Some pharmacies or clinics may supply compounded versions of medicines like tirzepatide (Mounjaro, Zepbound) and semaglutide (Ozempic, Wegovy) to patients, but the FDA has issued safety warnings about this practice. Concerns have risen over active ingredients, side effects and labeling of these compounded products.
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Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.