Dealing with a malfunctioning or jammed insulin pen is frustrating and potentially dangerous. When an insulin pen fails to work correctly, it can disrupt your carefully calibrated insulin dosing and cause uncontrolled blood sugar levels. Not to mention the loss of hundreds of dollars worth of insulin...
So, let’s explore the reasons why insulin pens may be faulty and not work correctly. You will find practical tips and advice on troubleshooting common issues such as blocked needles, damaged pens, and other problems that can arise when using insulin pens.
Related article: Does Insulin Need to Be Refrigerated? How to Store your Pens Correctly?
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How Do Insulin Pens Work?

Insulin pens are designed to be convenient, easy to use, and more discreet than traditional vials and syringes. They also allow for more precise insulin dosing, which can help people with diabetes better manage their blood sugar levels. Additionally, insulin pen injections are often less painful than syringe injections, as pen needles are smaller and less intrusive.
There are two types of insulin pens: disposable and reusable. Disposable pens typically contain a 3mL insulin cartridge (generally equivalent to 300 units) and must be discarded once empty. Reusable pens work with rechargeable insulin cartridges.
Related article: A Step-by-Step Guide to Using Insulin Pens Correctly.

Different parts of an insulin pen

Insulin pens have several parts that work together to inject insulin subcutaneously (under the skin). While specific features may vary depending on the brand and model, here are common parts you will find on most insulin pens, including the Lantus SoloStar Pen, Levemir FlexPen, Humalog KwikPen, or Novolog FlexPen:

  • Pen body: This is the central part of the pen and contains the insulin cartridge, dial, and plunger mechanism.
  • Protective cap: Insulin pens come with an opaque protective cap that must be put back on after each use. It protects the insulin from exposure to light and the cartridge from breakage.
  • Insulin cartridge: This is where the actual insulin is contained. It’s generally a tiny see-through plastic cartridge with 300 units of U-100 insulin or 600 units of U-200 insulin. Disposable insulin pens come with an integrated cartridge you cannot remove, while reusable pens come with a rechargeable mechanism that allows you to change the cartridge once it's empty.
  • Dial mechanism: This numbered wheel or button allows the user to select the desired insulin dose. Some pens allow selecting units only, whereas others offer greater precision with half-unit dosing dials. 
  • Plunger mechanism: This part of the pen pushes the insulin out of the cartridge and into the needle.
  • Injection button: The button on the end of the insulin pen that the user presses to inject the insulin. 
  • Disposable needle: Insulin pens work with disposable single-use needles that the user connects to the pen before each insulin injection. Insulin pen needles are available in different types and sizes.


Insulin pen parts

Fig. Insulin pen parts - 
New generation insulin pens or smart insulin pens may have additional features, such as memory functions that allow users to track their insulin doses or audible and tactile feedback to confirm that the dose has been delivered.
Related article: Insulin Travel Cases: Must-Have Companions for Diabetic Travelers!

What can cause an insulin pen to malfunction?

Insulin pens are designed to be reliable and deliver accurate and consistent insulin doses. These medical devices undergo rigorous testing and quality control before being released.
However, like any device, insulin pens can malfunction or stop working for various reasons, such as damage, blockage, or incorrect use.
Here are the most common causes:

  • Empty or low insulin cartridge: If the insulin cartridge is empty or low, the insulin pen will not work, and you won’t be able to turn the dial button. Make sure to check the cartridge level and replace it as needed. 
  • Blocked needle: If the needle is blocked, the pen will not deliver insulin properly. That's why it's essential to prime your insulin pen before each injection and ensure you see a drop of insulin coming out of the needle tip.
  • Incorrect injection technique: If you don’t follow the instructions, the pen may not work at all. Make sure to follow the instructions provided with the pen.
  • Damaged pen or cartridge: If the insulin pen or cartridge is damaged, it may not work properly. Store the pen and cartridges properly and avoid dropping or damaging them.

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How to Fix a Jammed Insulin Pen?

The very first thing to do when your insulin pen is not working is read the manufacturer's instructions. They may contain valuable information specific to your type of pen. Here are some steps that may help you fix a jammed insulin pen:
Related article: Why and How to Prime Your Insulin Pen?

1. Check the insulin cartridge

Make sure that the insulin cartridge is not empty or near empty. If you use a reusable insulin pen, check that the cartridge is correctly inserted. Remove it and insert it back inside.
If the cartridge is empty or looks damaged, replace it with a new one (reusable pens) or take a new pen (disposable pens).

2. Check the needle

Sometimes insulin pen needles can be clogged with insulin or debris, damaged, or unopened. It’s also possible that you haven’t screwed the needle to the pen correctly.
To check the needle, try gently tapping the side of the pen with your fingers and perform a test injection in the air (priming). Sending insulin into the air like this allows for checking that the needle is open and working.
If no insulin comes out, remove the needle, and replace it with a new one.

3. Check for damage

If the pen or cartridge is damaged or defective, it may cause jamming. Inspect the pen and cartridge for any visible signs of damage, such as cracks, breaks, or leakage.
If you see any damage, do not use the pen; replace it with a new one instead. Do not try to fix a broken or faulty insulin pen, as unsuccessful fixing could lead to inaccurate insulin dosing and seriously affect your blood sugar levels.
Related article: 10 Tips That Work to Inject Insulin Without Pain!

What to do if your insulin pen is still not working?

If the above steps do not resolve the issue and your insulin pen is not working correctly, take a new pen from the fridge and ask your doctor or pharmacist for further guidance.
Never force the pen or plunger, as this can damage the pen and cause unsafe insulin delivery.
Additionally, it is important to properly store and handle insulin pens and cartridges to prevent jamming or other issues from occurring in the first place.
Related article: The Parent’s Guide to a Happy Childhood with Diabetes!
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Faulty Insulin Pens: FAQs

How to reset an insulin pen?

Standard insulin pens do not have any electronics. They’re purely mechanic, so there’s no “reset” option. However, when you find your insulin is not working, you may reset the injection mechanism by priming your pen again:

  1. First, make sure a needle is attached to the pen.
  2. Hold the insulin pen with the needle pointing upward.
  3. Gently tap the pen with your fingers to remove any air bubbles.
  4. Turn the dial button to select 2 units of insulin.
  5. Hold the insulin pen with the needle pointing upward and press the injection button until insulin comes out of the needle. This will prime the pen and reset the mechanism.
  6. If no insulin comes out of the needle, repeat the reset process until you see at least a drop of insulin.

Smart insulin pens generally have a reset option. They work with Bluetooth technology and are linked to an App that tracks your insulin dosing history, blood sugar levels, and other important personal details for insulin therapy. Most of the time, you can reset the app and the data it contains from your phone.
Related article: How to Put Up With (and Support!) Your Diabetic Wife or Husband?

Can you dial back an insulin pen?

Most insulin pens allow you to dial backward your insulin dose, so if you’ve selected too many units of insulin, you may dial back to reduce the number.
Insulin dosing accuracy is essential for blood sugar management. Injecting too much insulin can cause severely low blood glucose (hypoglycemia). Always double-check the selected number of insulin units before injecting. If you aren’t sure whether you can dial back a specific pen, inject the selected dose in the air and dial a new one.

What to do with jammed or damaged insulin pens?

Whether faulty, jammed, or empty, standard disposable insulin pens can be disposed of in your household trash once the needle has been removed and placed into a sharps container.
If you have a reusable or smart insulin pen, read the manufacturer’s instructions about what to do when your pen isn’t working.
Related article: What Happens if You Miss a Dose of Insulin?
We would love to hear from you! Have you ever encountered a jammed insulin pen? How did you handle the situation? Sharing your experience is valuable to others!

April 04, 2023


4AllFamily Customer Care Team said:

Hi Constance,
I’m sorry to hear that you’re experiencing a problem with your Ozempic pen. However, we’re unable to provide direct assistance in that regard. It’s best to contact the manufacturer or your healthcare provider or pharmacist to get a remplacement.
Best regards,

Constance Taylor said:

I have a jammed ozempic pen and I need a rep

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