Overview
If a Mounjaro® pen is difficult to use or does not release medication as expected, follow the troubleshooting steps below to check whether the Mounjaro® pen is functioning correctly.
Use this article when you want to:
Identify the common signs that your Mounjaro® pen is not working properly
Troubleshoot a Mounjaro® pen with a dose knob that's hard to press
Understand what to do if your Mounjaro® pen still doesn't work after troubleshooting
Learn how to prevent Mounjaro® pen problems through correct injection technique, needle use, and storage
What Are the Common Signs of a Mounjaro® Pen Issue?
If your Mounjaro® pen isn't working properly, you may notice one or more of the following:
The dose knob is hard to press or won't press down fully
No liquid comes out when you press the dose knob
The dose knob doesn't return to its starting position after your injection
You don't see a drop of liquid at the needle tip during the pre-injection check
The pen looks damaged, cracked, or leaking
If you notice any of these signs, do not use the pen. Follow the troubleshooting steps below before attempting your injection again.
How Do I Troubleshoot a Hard-to-Press Dose Knob?
If the dose knob on your Mounjaro® pen is hard to press, work through the following steps in order:
Check that you've removed both the pen cap and the inner needle cap before injecting.
Confirm the needle is attached straight and securely to the pen.
Check that you have not exceeded the number of doses your Mounjaro® pen is designed to deliver.
Try gently warming the pen by holding it in your hands for a few minutes — a cold pen can make the dose knob harder to press.
Attach a new needle and try again, as the needle itself may be the cause of the resistance.
If the dose knob is still hard to press after working through these steps, do not force it. Move on to the next section.
What If My Mounjaro® Pen Still Doesn't Work?
If you've worked through the troubleshooting steps above and your Mounjaro® pen still isn't working properly, do not continue trying to use it, and do not force the dose knob. The pen may be unusable.
How Can I Prevent Mounjaro® Pen Problems?
You can reduce the chance of your Mounjaro® pen developing a fault by following correct technique, needle use, and storage practices.
Injection Technique
Always check for a drop of liquid at the needle tip before injecting, as described in your Mounjaro® pen instructions
Press the dose knob down fully and hold it in place for the full count before removing the needle from your skin
Avoid pressing the dose knob before the needle is inserted into your skin
Correct Needle Use
Use a new needle for every injection
Never reuse a needle, as a used needle can become blunt or blocked
Attach the needle straight and securely to the pen before each injection
Proper Mounjaro® Pen Storage
Store your Mounjaro® pen in the fridge (2–8°C) before first use
Once in use, you can store your Mounjaro® pen at room temperature, away from direct heat and light, for up to 30 days
Always keep the pen cap on when your Mounjaro® pen is not in use
Never store your Mounjaro® pen in a freezer, and never use a pen that has been frozen
Following these steps consistently will help keep your Mounjaro® pen working as intended.