How to inject Mounjaro: A step-by-step guide

Key Points

• Mounjaro can be injected in your abdomen, thigh, or upper arm
• Proper injection technique includes pressing the button on the injector pen for 10 seconds and listening for two clicks
• Taking Mounjaro out of the refrigerator 30 minutes before injection may reduce discomfort
• Rotating injection sites weekly helps prevent skin irritation and other problems

Looking at a Mounjaro pen for the first time can be a bit intimidating. Most of us weren't taught how to give ourselves injections, and it's perfectly normal to feel uncertain at first.

The good news is that this process gets easier with practice. What seems complex now will likely become a routine part of your weekly schedule before long.

Whether you're using Mounjaro for type 2 diabetes or for another reason, proper injection technique ensures you get the full benefit of your medication. Let's walk through the process step by step.

What is Mounjaro? How does it work?

Mounjaro (tirzepatide) is a prescription medication approved by the FDA for managing blood sugar in adults with type 2 diabetes. It belongs to a class of medications called GIP/GLP-1 receptor agonists.

Mounjaro works by mimicking the effects of two natural hormones in your body:

1. GLP-1 (glucagon-like peptide-1): This hormone helps control your appetite, slows down how food moves through your digestive system, helps stabilize blood sugar levels, and leads to weight loss
2. GIP (glucose-dependent insulinotropic polypeptide): This hormone works with GLP-1 to help manage blood sugar and regulate how your body stores energy.

Unlike some diabetes medications that only target one hormone, Mounjaro engages both, which is what makes its approach to blood sugar management distinctive.

Mounjaro is administered as a once-weekly subcutaneous injection (under the skin). It comes in a pre-filled single-dose pen in various strengths (2.5 mg, 5 mg, 7.5 mg, 10 mg, 12.5 mg, or 15 mg), allowing your doctor to adjust your dosage as needed.

Where to inject Mounjaro

You have three options for where to inject Mounjaro:

• Your abdomen (stomach area): Avoid the area around your belly button
• Your thigh: Use the outer part of your thigh, not the inner thigh
• The back of your upper arm: You may need someone to assist you with injecting in this site

What’s the best spot to inject Mounjaro?

There is no single "best" spot that works for everyone. The good news is that your body absorbs about the same amount of medication regardless of where you choose to inject.

According to Gia Eapen, MD, “Some people find stomach injections less painful than injections in the thigh. This makes sense considering your abdomen typically has more fatty tissue under the skin, which can provide more cushioning. It really comes down to personal preference.”

The Importance of rotating injection sites

Using the same exact spot week after week could lead to irritation, swelling, or other skin problems. This is where rotating your injection sites can help.

You have two simple options:

1. Rotate between different body areas each week (abdomen one week, thigh the next)
2. Stay in the same general area but move the location (right side of your stomach one week, left side the next)

Either approach works well. The main point is not to inject in the same spot repeatedly.

Storing your Mounjaro

According to Lilly, the manufacturer of Mounjaro, you can keep your Mounjaro pens in the refrigerator between 36°F to 46°F, which is the standard refrigerator temperature range. If you're traveling, an unopened pen can remain at room temperature (up to 86°F) for up to 21 days.

A few important reminders:

• Don't freeze your pens
• Keep them in their original packaging to protect them from light
• Handle with care because there's glass inside
• If you drop the pen on a hard surface, it's safer to use a new one

💡Tip

Eapen, MD, says, “Consider taking your Mounjaro pen out of the refrigerator about 30 minutes before you inject to make the process more comfortable. Room-temperature medication tends to cause less discomfort than cold medication when injected.”

Step-by-Step injection guide

Step 1: Gather your supplies

It’s easier if everything you need is within reach before you begin. Here are the supplies you may need:

• Your Mounjaro pen
• An alcohol swab
• A cotton ball or gauze pad (optional but helpful)
• A sharps container for disposal

Step 2: Clean your injection site

Once you decide where you would like to inject:

1. Wash your hands thoroughly with soap and water
2. Clean the injection site with an alcohol swab
3. Let it air dry completely (don't blow on it to speed drying to keep it sanitary)

“A word of caution: avoid injection sites that are scarred, have bruises, are tender or irritated, or are too close to your belly button,” says Eapen, MD.

Step 3: Prepare the Mounjaro pen

Your Mounjaro pen comes with the needle already attached, so the process is simple.

1. Verify that the pen is locked (look for the closed padlock symbol)
2. Check that the medication is clear and colorless to slightly yellow
3. Confirm the expiration date hasn't passed
4. Remove the gray base cap (don't replace it, as this could damage the needle)

Step 4: Inject the medication

Now, here are the steps to inject Mounjaro:

1. Place the flat base of the pen against your skin at a 90-degree angle
2. Turn the lock ring to unlock it (look for the open padlock symbol)
3. Press and hold the purple button for at least 10 seconds
4. Listen for two distinct clicks:
   • First click: This signals the injection has started
   • Second click: This indicates the injection is complete
5. Look for the gray plunger in the window, which confirms the medication has been delivered
6. Gently remove the pen from your skin

If you notice a drop of blood, simply dab it gently with a cotton ball or gauze without rubbing the area.

Step 5: Dispose of the pen

Place the used pen in an FDA-approved sharps container. Never dispose of used injection pens in regular household trash.

If you don't have a sharps container, a heavy-duty plastic container with a tight-fitting lid can serve as an alternative.

How to know if you injected correctly

Signs of a successful injection

You can confirm you've injected Mounjaro correctly when:

1. You heard both clicks during the injection process
2. You can see the gray plunger in the pen's window
3. You kept the pen against your skin for the full 10 seconds

Eapen, MD, notes, “It's normal to see a small drop of medication on the needle tip after removing the pen. This doesn't mean you missed part of your dose.”

Mistakes to avoid

While the process of injecting Mounjaro can be simple, here are some common errors to avoid:

• Removing the pen before the second click
• Not holding the pen firmly against your skin at a 90-degree angle
• Injecting through clothing instead of directly onto clean skin
• Using the same injection site repeatedly
• Forgetting to unlock the pen before attempting to inject

Injection site reactions

“Watch for any signs of redness, swelling, bruising, itching, or irritation at the injection site. These reactions may be temporary and resolve themselves within a few days,” cautions Eapen, MD. “If they do not, please contact your healthcare provider immediately.”

When to call your doctor

Reach out to your healthcare provider if you experience:

• Severe pain or excessive swelling that doesn't improve in a few days
• Signs of potential infection, like unusual warmth, discharge, or spreading redness
• Persistent or intense itching
• Any reaction that seems unusual or concerning

Final thoughts: How to inject Mounjaro

Learning to inject Mounjaro may seem challenging at first, but with practice, the process becomes more familiar and routine. What initially might feel complex will likely become a straightforward part of your weekly schedule over time.

The key elements to remember are choosing an appropriate injection site, rotating locations, holding the button for the full 10 seconds, and listening for both clicks during the injection.

If you're uncertain about your injection technique, don't hesitate to ask your healthcare provider for a demonstration or additional guidance. They can offer personalized advice tailored to your specific situation.

Mounjaro works best with a nutritious diet. A registered dietitian can customize a Mounjaro diet for you. 

Frequently Asked Questions (FAQs)

1. What if I miss a dose of Mounjaro?

According to Lilly, the manufacturer of Mounjaro, if you miss a dose, the timing matters. If it's been 4 days (96 hours) or less since your missed dose, take it as soon as possible and then continue with your regular schedule. However, if it has been more than 4 days since the missed dose, skip it entirely and wait until your next regularly scheduled injection day.

Important safety note: Don't take two doses within 3 days of each other under any circumstances.

2. Does the time of day matter for my injection?

Eapen, MD says, “You can take Mounjaro at any time of day that works for your schedule. The important thing is consistency with your weekly schedule. If you need to change your usual injection day, ensure there are at least 3 days (72 hours) between doses.”

3. Can someone else administer my injection?

If you're not comfortable giving yourself an injection, a caregiver, family member, or friend can help. The back of the upper arm is particularly convenient when someone else is administering the injection, as it's difficult to reach this area yourself. Please ensure that they wash their hands thoroughly with soap and water before administering your Mounjaro injection.

4. How can I tell if my medication is still good?

Look at the window on the Mounjaro pen. If the liquid in it is clear and colorless to slightly yellow, you can proceed to inject yourself. Do not use the pen if you notice particles, cloudiness, or a color change. Do not use a pen that has been frozen or has been dropped on a hard surface.

5. How do I optimize my weight loss on Mounjaro?

Proper injection technique is just one part of maximizing your results with Mounjaro. Tirzepatide clinical trials showed the following weight loss results. After 72 weeks, participants lost an average of 15% of their starting weight on 5mg weekly, 20% on 10mg weekly, and 21% on 15mg weekly.

These weight results were achieved by using Mounjaro and a nutritious diet, and regular exercise.

Since there is no single "best" Mounjaro diet plan that works for everyone, consider working with a registered dietitian who can create a personalized nutrition plan tailored specifically to your needs and goals.

Get the best Mounjaro diet plan for you from a dietitian who accepts your insurance.

The views expressed by authors and contributors of such content are not endorsed or approved by Fay and are intended for informational purposes only. The content is reviewed by Fay only to confirm educational value and audience interest. You are encouraged to discuss any questions that you may have about your health with a healthcare provider.