If this is your first time taking Mounjaro, you may have questions about where and how to give an injection. 

Image of person injecting a medicine via pen into their abdomen

Key facts

  • Mounjaro is a prescription diabetes drug that comes in one-time-use pens that let you inject the medication. The drug is available in six different doses.
  • You should inject Mounjaro into parts of your body that tend to have more fat, such as your belly, upper arms, thighs, or hips. 
  • Consider changing injection sites frequently to prevent scar tissue from forming. Avoid injecting into muscular or lean areas, veins, or arteries.
  • Mounjaro is administered under the skin once per week. The dose you administer will vary based on your health situation and needs as determined by your doctor. 
  • It is important to take the medicine consistently on the same day and at the same time weekly.

Table of Contents

Get to know your Mounjaro pen, prescription, and dose

Before you inject your medication, you should be familiar with the pen and pen needle, your prescription, and your dose. 

Mounjaro comes in a single-dose injectable pen, which many people refer to simply as a “pen.”

Mounjaro pens are about six inches long with a hidden pen needle on one end and a small plunger button on the other end that will automatically inject the medication. 

There are six different pens available, depending on the dose your doctor or other qualified healthcare professional prescribes. 

The manufacturer designed each pen to deliver only one dose, reducing the odds of someone overdosing on the medication. 

The pen should be thrown away in a sharps container after a single use. 

If you’ve never used a pen, your doctor’s office or pharmacist can give you information on how to safely use your Mounjaro pen. 

The manufacturer, Eli Lilly, also has a website describing how to safely inject the medication.

What does a dose look like?

The dose your healthcare provider prescribes will vary depending on your weight, height, lifestyle, and health goals. 

Mounjaro is administered subcutaneously (underneath your skin) once per week.

The different dosing options available are: 

  • 2.5 mg per week (for the first four weeks as a starting dose)
  • 5 mg per week 
  • 7.5 mg per week 
  • 10 mg per week 
  • 15 mg per week

Please note: Each dose comes in a single-use pen designed to deliver the entire dose in a liquid amount of 0.5 mL. 

Your doctor will determine the appropriate maintenance dose for you, ranging from 5 mg to 15 mg per week.

Never take more Mounjaro than your doctor prescribed. 

Where is the best place on my body to inject Mounjaro?

Always rotate (or switch up) your injection sites to prevent the buildup of scar tissue. 

Mounjaro is best injected into fatty tissue, such as areas around the abdomen, upper arms, upper thighs, and hips. 

It’s not recommended to inject into lean or mostly muscular parts of the body. 

Injections in these areas tend to be painful, may bleed more than normal, and can cause the medication to be less effective. (Injections into fatty tissue may cause slight pain or discomfort.)

Mounjaro should never be injected into a vein or artery. 

How to inject Mounjaro

You should inject the amount of medicine your doctor prescribed under the skin into fatty tissue no more than once per week, ideally on the same day at the same time. 

The time of day for your injection usually does not matter — choose the time that works best for you to be consistent with the process.

The steps to follow for injecting Mounjaro are outlined below.

Get your supplies ready 

For best results, use a 28- to 31-gauge needle more than 2.1 millimeters (mm) long that can deliver the 0.5 mL dose of Mounjaro that your healthcare provider prescribed.

Get your Mounjaro pen and an alcohol swab ready. 

Check your dose to make sure you have the correct pen. 

Remove the cap from the front part of your pen and look through the pen’s plastic window to make sure the liquid inside the pen is clear. 

If the liquid is discolored, cloudy, frozen, or has particles floating in it, do not use it. 

Find a good spot on your body and prepare the site for the shot

Choose an area on your body with fatty tissue, such as your stomach, hips, upper thighs, or upper arms.

Prepare the site on your skin by quickly rubbing it with an alcohol swab and letting it air dry. 

Injecting while the alcohol is still wet may cause stinging. 

Injecting Mounjaro 

Make sure your pen is locked, and do not unlock it until you place the base of the pen on your skin and are ready to inject.

To unlock your pen, remove the gray cap by pulling it away from the clear base. You will then throw away the gray cap.

Note: You do not have to discard the cap in a special container. It’s OK to discard the gray cap in the household trash. 

Now, the needle will be exposed. Do not touch the needle, or you will contaminate it. 

Place the clear base against your skin, and unlock the pen by turning the lock ring. 

Press the top of the pen. This will release the medication. 

The first click you’ll hear is when the injection is starting, followed by a second click a few seconds later. This lets you know that the injection has finished. 

Hold the pen against your skin for up to 10 seconds to make sure all of the medication has been dispersed. 

You will know the injection is complete when you can see the gray plunger through the glass.

Remove the pen from your skin. 

Wipe away any blood or medication that has bubbled to the surface of your skin with a clean alcohol swab.

Discard the Mounjaro pen safely 

Since Mounjaro pens are only good for one-time use, you will then discard the pen in a sharps container. 

Do not throw the pen away with regular trash. Do not recycle your pen. 

How do I know if I injected Mounjaro correctly?

You will know if you’ve injected your medication correctly if you hear two clicks (one at the beginning of your injection and one at the end).

Do not remove the pen until you hear the second click. These clicks are loud and detectable to most people. 

Some people may hear a soft click right before the second loud click. That is normal. 

Do not remove the pen from your skin until you hear the second loud click.

You will also see the gray plunger if your dose was administered correctly. 

If you do not see the gray plunger, contact Eli Lilly at 1-800-Lilly-Rx (1-800-545-5979) for further guidance. 

What is the best time of day to inject Mounjaro?

The best time of day to take Mounjaro is when you’ll remember to take it. 

There is no official best time, but people usually pair their Mounjaro shot with other routine activities — such as eating breakfast or making their morning coffee. 

You can take your weekly dose at any time of day, but you should plan to take it on the same day each week. 

What do I do if I miss a dose of Mounjaro?

Don’t panic — this is OK. Missing one dose will not drastically increase your insulin resistance or make you gain weight. 

However, the medication works best when it’s taken consistently. 

You can also take your dose a few days late. Just make sure to then change the day of the week that you routinely take your shot to repeat on the same day each week. 

Also, when changing the day you take your next dose, never take the next dose less than three days (or 72 hours) from the time of the missed dose.

For example, if you always take your Mounjaro on Sundays but didn’t take your shot until Tuesday morning, you should wait until the following Tuesday to take your next dose.

However, if you missed your dose more than four days (96 hours) ago, just skip that week’s dose and take your regularly scheduled dose on time. 

How do I properly store Mounjaro? 

Store your pen in the refrigerator between 36 degrees to 46 degrees Fahrenheit (2 degrees to 8 degrees Celsius).

You may also store your pen at room temperature up to 86 degrees Fahrenheit (30 degrees Celsius) for up to 21 days.

Never freeze your pen. If the pen has been frozen, throw the pen away and use a new one. 

Store your pen in the original carton to protect it from light exposure and heat. 

The pen has glass parts. Handle it carefully.