Mounjaro Pen Malfunction: 5 Steps To Take If It Happens (2024)

Mounjaro Pen Malfunction: 5 Steps To Take If It Happens (1)

Managing your diabetes or weight loss plan can be challenging, especially when you face some unexpected issues with your medication.

If you’re using the Mounjaro Pen and it malfunctions, it can be frustrating and concerning. But don’t worry there are some simple steps you can take to handle such situations effectively.

In this guide, we’ll show you simple steps to fix a Mounjaro Pen problem so you can stick to your treatment plan. We’ll also give you some helpful tips to avoid these issues next time which makes it easier for you to manage your condition.

Understanding Mounjaro and its Pen

Mounjaro, also known as tirzepatide, is a prescription medication approved by the FDA for treating type 2 diabetes in adults. It helps control blood sugar by working on hormones like GLP-1 and GIP.

Mounjaro is not a cure for type 2 diabetes but a medication to manage the condition. It should be used alongside other diabetes management strategies like diet, exercise, and prescribed medications. It’s administered once a week using the Mounjaro Pen.

The Mounjaro Pen is a disposable, pre-filled device designed to deliver this medication through a once-weekly injection under the skin. It’s suitable for self-administration at home which makes it convenient for people with diabetes to adhere to their treatment plan.

Do Not Use Your Mounjaro Pen If

Knowing when not to use your Mounjaro Pen is crucial. Here are some red flags:

  • If the pen appears damaged or has passed its expiration date, do not use it.
  • If the pen wasn’t stored as per the guidelines (e.g., kept in extreme temperatures), it’s best not to use it.
  • If the medication inside appears discolored or contains particles, avoid using the pen.
  • If you’re not sure about any of the above, consult your healthcare provider before using the pen.

Being aware of these conditions helps ensure your safety and the medication’s efficacy.

RELATED: Switching from Trulicity to Mounjaro: A Patient’s Guide

How to Self-Inject the Mounjaro Pen

Mounjaro Pen Malfunction: 5 Steps To Take If It Happens (2)

Self-injecting the Mounjaro Pen is a simple process. But It’s crucial to follow your doctor’s instructions and refer to the official Mounjaro Pen leaflet for detailed steps. Here’s a general process overview:

  • Prepare the Pen: Before injecting, wash your hands thoroughly with soap and water. Take the Mounjaro Pen out of the refrigerator at least 30 minutes before injection to allow it to reach room temperature.
  • Choose Your Injection Site: Common injection sites include the abdomen, thigh, or upper arm. Rotate injection sites weekly to avoid skin irritation.
  • Remove Cap and Prime the Pen: Remove the pen cap and follow the manufacturer’s instructions to prime the pen. This step ensures the medication is ready for injection and helps eliminate air bubbles.
  • Position and Unlock: Firmly place the pen against your selected injection site, then unlock it to prepare for injection.
  • Press and Hold for 10 Seconds: Press the button to deliver the dose. Keep the pen against your skin for up to 10 seconds, even if you don’t feel the needle. The injection is done when you hear 2 clicks and see the grey plunger.
  • Dispose of the Pen: Once the injection is complete, dispose of the pen in a proper sharps disposal container. Do not reuse the pen.

These steps are from the Eli Lilly official site and should be followed carefully to use Mounjaro correctly. These are not the complete instructions for using Mounjaro. Your healthcare provider should demonstrate how to use the pen before you start Mounjaro. Read theInstructions for Useincluded with your pen.

Signs of a Faulty Mounjaro Pen

Recognizing a malfunctioning Mounjaro Pen is crucial to ensure the effectiveness of your treatment and your safety. Here are some signs which show your pen might be faulty:

  • No Click Sound: When you press the button to inject, you should hear a clear click that shows the medicine has been released. If you don’t hear this click, the pen might not be working right.
  • Difficulty in Pushing the Button: The injection button should depress smoothly. If it feels jammed or unusually hard to press, stop using the pen and consult your provider.
  • Incomplete Injection: If medication leaks from the injection site or the pen, it could mean the device did not deliver the full dose. This can compromise your treatment.
  • Rapid Expiration Date: Always check the expiration date before use. If the pen is near or past its expiration date, it might not work as intended.
  • Visible Damage: Inspect the pen for any signs of damage like cracks, leakage, or broken components. Any visible defects mean the pen should not be used.

If you experience any of these issues, contact your provider immediately to discuss whether a replacement pen is needed and how to proceed with your treatment in the interim.

RELATED: Zepbound pen malfunction: 4 steps to take if it happens

Steps to Take for Mounjaro Pen Malfunction

1. Inspect the Pen

Before using the Mounjaro Pen, it’s important to check it carefully. Look at the pen to see if it has any cracks, leaks, or broken parts. Make sure the medicine inside is clear and doesn’t have any particles or strange colors. This step helps keep you safe and makes sure the medicine works well.

2. Don’t force the injection

If you have trouble injecting with the Mounjaro Pen, stop right away. Don’t force it, as that might break the pen or give you the wrong dose, which can be unsafe. Check to make sure the pen is in good condition, not expired, and stored properly. If everything seems fine but it’s still difficult to use, look at the official instructions or talk to your healthcare provider for help.

3. Check for Air Bubbles

Air bubbles can interfere with the proper delivery of your medication. Before injecting, inspect the medication inside the Mounjaro Pen through the viewing window. If you see air bubbles, follow the manufacturer’s instructions to remove them.

This usually involves holding the pen with the needle pointing upwards and tapping the side to move the bubbles to the top, then pressing the button to expel the air. Ensuring the pen is free of air bubbles is crucial for accurate dosing and effective treatment.

4. Follow Storage Guidelines

To keep your Mounjaro Pen working well and safe, store it properly. Always keep it in its original box to protect it from light and put it in the fridge between 36°F and 46°F (2°C to 8°C). Do not freeze it, and if it gets frozen, don’t use it.

If you can’t refrigerate it, you can keep it at room temperature, up to 86°F (30°C), for up to 21 days. Avoid very hot or cold temperatures and keep it out of direct sunlight.

5. Contact Your Healthcare Provider

If you face any problems with your Mounjaro Pen or are worried about how it works, contact your doctor right away. They can tell you if you should keep using the pen or need a new one. Your doctor can also help you fix any issues, talk about any risks, and make sure your treatment stays on track. Speaking to your doctor quickly helps keep your medication safe and effective.

RELATED: Wegovy Pen Malfunction: 5 Steps To Take If It Happens

Possible Causes Your Mounjaro Pen Might Malfunction

Several reasons can cause your Mounjaro Pen to malfunction, including:

  • Improper Storage: Exposing the pen to extreme temperatures or direct sunlight can affect its functionality.
  • Physical Damage: Cracks or leaks in the pen can result from dropping or mishandling the device.
  • Manufacturing Defects: Occasionally, a pen may have defects from the production process, affecting its performance.
  • Expired Medicine: Using a pen past its expiration date can lead to reduced efficacy or malfunction.
  • Incorrect Priming: Failing to prime the pen according to instructions can cause improper dose delivery.

Tips to Avoid Mounjaro Pen Issues

To ensure your Mounjaro Pen works well and delivers the appropriate dose, keep these tips in mind.

  • Store Properly: Always keep your Mounjaro Pen in the refrigerator at 36°F to 46°F (2°C to 8°C) and protect it from light. Never freeze the pen.
  • Handle with Care: Avoid dropping or mishandling the pen to prevent physical damage like cracks or leaks.
  • Check Expiry Dates: Regularly inspect the expiration date on the pen and never use it past this date.
  • Inspect Before Use: Always check the pen for visible damage and ensure the medication is clear and particle-free before every use.
  • Avoid Air Bubbles: Hold the pen with the needle pointing upwards and tap the side to move any air bubbles to the top before expelling them.
  • Follow Procedures: Adhere strictly to the user guidelines provided by the manufacturer and demonstrated by your healthcare provider.
  • Don’t Force the Injection: If you experience difficulty while injecting, stop immediately and consult your healthcare provider.

Can I Send My Mounjaro Pen Back if It Malfunctions?

No, you usually cannot return a malfunctioning Mounjaro Pen to the manufacturer. This is mainly due to safety and regulatory reasons.

Medical devices, like injection pens, have to follow strict guidelines to keep patients safe. Sending back a used pen could break these rules and create safety risks if not handled properly.

A malfunctioning pen might have broken parts or be contaminated, and returning it could increase the risk of injury or infection for healthcare workers or anyone else who comes into contact with it.

What to Do Instead:

  • Contact Your Doctor: Report the issue to your doctor immediately. They can guide you on obtaining a replacement pen and make sure you don’t miss any doses of your medication.
  • Dispose of Safely: Follow your doctor’s advice or local guidelines for disposing of sharps. This typically involves placing the malfunctioning pen in a designated sharps container.


In Conclusion, understanding the proper use, storage, and troubleshooting of your Mounjaro Pen is crucial for effective treatment and safety. By following the outlined steps, avoiding common issues, and consulting your provider as needed, you can ensure the reliability of your medication delivery system. Always prioritize proper handling and storage to maintain the pen’s functionality and efficacy.


What should I do if my Mounjaro Pen malfunctions mid-injection?

If your Mounjaro Pen malfunctions mid-injection, stop immediately and do not try to inject the remaining medication. Contact your healthcare provider for guidance on what to do next and to obtain a replacement pen. Ensure that you follow any disposal instructions for the malfunctioning pen.

How often should I check my Mounjaro Pen for issues?

You should inspect your Mounjaro Pen before each use to ensure there are no visible signs of damage, the medication is clear and free of particles, and there are no air bubbles. Regular checks will help prevent malfunctions and ensure accurate dosing.

What happens if Mounjaro freezes?

If Mounjaro freezes, it should not be used. Freezing can compromise the effectiveness and safety of the medication. Dispose of the frozen pen according to your doctor’s recommendations or local guidelines and obtain a replacement.

Is there a phone number to report a Mounjaro pen malfunction?

Yes, there is a phone number to report a Mounjaro pen malfunction. If you experience any issues with your Mounjaro Pen, you can report the malfunction by contacting the Lilly products customer service hotline at 1-800-Lilly-Rx (1-800-545-5979) or reach out to Lilly’s website, the manufacturer of Mounjaro Pen.


Mounjaro Pen Malfunction: 5 Steps To Take If It Happens (2024)
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