Pain from the injection has not been reported as a common side effect with Mounjaro, but may occur. Because Mounjaro is given as an injection under the skin (subcutaneously), there is the possibility of slight pain or discomfort. You, or a caregiver, will be taught how to properly give the injections to help lessen any pain at the injection site.

Mounjaro (generic name: tirzepatide) is given from an injection pen. Be sure to rotate the site of your injection each week. This can help to lessen any irritation. Mounjaro is stored in the refrigerator. Bringing the medicine to room temperature for 30 minutes before injection may also help to lessen injection pain. If preferred, you may store your pen at room temperature up to 86°F (30°C) for up to 21 days.

Mounjaro is used to treat adults with type 2 diabetes, in addition to diet and exercise, but may also lead to weight loss (although it is not yet approved for that use). It was first approved in May 2022 and there are limited reports from patients about how the Mounjaro injection feels. One user has noted that “I didn’t even feel the needle”, and other reports have called it "painless", but everyone’s experience is different. Talk to your doctor about how the injection may feel if you are concerned.

Learn more: Mounjaro User Reviews

Does Mounjaro cause injections site reactions?

Yes, injection site reactions have been reported to occur with Mounjaro, but this is not a common side effect. In placebo-controlled studies, injection site reactions were reported in 3.2% of patients who received Mounjaro compared to 0.4% those who received a placebo (an inactive treatment).

• Injection site reactions typically involve areas of redness, warmth, irritation, swelling or minor pain.
• For example, you may have experienced this type of reaction after a vaccine or other shot. Injection site reactions typically go away on their own in a day or two.
• Ask your healthcare provider if you can use warm compresses, ice or a mild pain-reliever like acetaminophen (Tylenol) to help relieve any pain after your injection.
• If your injection site continues to be irritated, contact your doctor.

Researchers also found that more patients who developed antibodies to tirzepatide (the active ingredient in Mounjaro) also had allergic (hypersensitivity) reactions like itching, eczema or injection site reactions.

• Allergic reactions occurred in 4.1% (106 / 2,570) of patients with antibodies and in 3% (73 / 2,455) of patients who did not develop antibodies.
• Injection site reactions occurred in 4.6% (119 / 2,570) of people who had antibodies, and in 0.7% (18 / 2,455) of people who did not have antibodies.

There was no identified clinically significant effect of antibodies on the effectiveness of Mounjaro or how it was metabolized or excreted.

To learn more about Mounjaro side effects visit here.

How do I use Mounjaro?

Do not use this medicine unless your healthcare provider has instructed you on its proper use, storage and disposal. Use Mounjaro exactly as directed by your healthcare provider.

Mounjaro is available as a 2.5 mg, 5 mg, 7.5 mg, 10 mg, 12.5 mg and 15 mg subcutaneous injection in a single-dose auto-injector pen. The recommended starting dosage is 2.5 mg subcutaneously once weekly, increasing to 5 mg once weekly after 4 weeks. The maximum dosage is 15 mg subcutaneously once weekly. Mounjaro may be taken with or without food.

Mounjaro is injected under the skin (subcutaneously) of your stomach (abdomen), thigh, or upper arm one time per week, at any time of the day. You may change the day of the week you use Mounjaro as long as the time between the 2 doses is at least 3 days (72 hours).

Mounjaro is given from a single-dose injection pen. This means that one dose of the medicine is already in the pen and does not require mixing. The needle is hidden inside the pen and there is no need to see it or handle it.

Remove the pen from the refrigerator before injection; it does not have to be brought to room temperature. However, bringing it to room temperature for 30 minutes or so may make the injection more comfortable. Leave the gray base cap on until you are ready to inject.

Before you inject, be sure the medicine is not expired and the pen is not damaged. Check to be sure the medicine is not cloudy, frozen, or contains particles. The liquid should be colorless to slightly yellow. If it looked damaged or contaminated, do not use it and get a new pen.

Follow these five steps to use your Mounjaro pen:

• Wash your hands.
• Choose an injection site. You or someone else can inject the medicine in your stomach, or thighs. Another person should give you the injection in the back of your upper arm.
• Pull off the gray base cap. Do not put the gray base cap back on as this could damage the needle. Throw the cap away in the trash. Don’t touch the needle.
• Place the clear base flat on your skin, then unlock.
• Press and hold the purple injection button for up to 10 seconds. Listen for the first click. This means the injection has started. The second click means that the injection is complete. You will know your injection is complete when the gray plunger is visible.
• After your injection, place the used pen in a sharps container.

These are NOT the complete instructions for using Mounjaro. The manufacturer Instructions for Use also display pictures of the pen and how to administer. Read the full Instructions for Use included with your pen and each time you get a refill. Ask your doctor or pharmacist if you have any questions.

Additional information

Be sure to rotate (change) the injection site (give it in a different area than the time before) each week. This will help to lessen any pain or irritation at the injection site. You may use the same area of your body but be sure to choose a different injection site in that area.

Do not mix insulin and Mounjaro together in the same injection. You may give an injection of Mounjaro and insulin in the same body area (such as your stomach area), but not right next to each other.

If you miss a dose, take the missed dose as soon as possible within 4 days (96 hours) after the missed dose. If more than 4 days have passed, skip the missed dose and take your next dose on the regularly scheduled day. Do not take 2 doses within 3 days of each other.

You may give an injection of Mounjaro and insulin in the same body area (such as your stomach area), but not right next to each other.

If you take too much or overdose, call your healthcare provider.

Storage and handling

• Store your pen in the refrigerator between 36°F to 46°F (2°C to 8°C). Store your pen in the original carton to protect it from light.
• You may store your pen at room temperature up to 86°F (30°C) for up to 21 days.
• Do not freeze the pen. If the pen has been frozen, throw it away and use a new one.
• The pen has glass parts and should be handled carefully. If you drop the pen on a hard surface, do not use it. Use a new pen for your injection.
• Keep your pen and all medicines out of the reach of children and pets.

Follow these instructions for proper disposal of your pen.

This is not all the information you need to know about Mounjaro (tirzepatide) for safe and effective use and does not take the place of your doctor’s directions. Review the full product information and discuss this information and any questions you have with your doctor or other health care provider.