Faulty Wegovy and Mounjaro Pens: Troubleshooting Guide

Weight loss injections such as Wegovy and Mounjaro have given many people an effective way to manage their weight and improve overall health. While these treatments are generally reliable, there may be times when the injection pen does not work as expected. That is why it is important to know how to troubleshoot common issues, recognise whent ot stop using a pen and understand when to reach out for professional support.

At Batley Pharmacy, we are here to guide you through the process and provide clear advice on what to do if your Wegovy or Mounjaro pen is faulty.  

Wegovy Pen Troubleshooting

The Wegovy injection pen is designed for single use and delivers a pre-measured weekly dose of semaglutide. If your Wegovy pen is not working, these are the most common problems and solutions.

1. Wegovy pen not clicking

When you press the start button, you should hear a distinct click. If it does not click:

• Ensure the needle cap is removed fully before use.
• Check if the dose button is fully pressed.
• If the pen still does not click, do not force it. Forcing could damage the device or cause injury.

If the pen still fails after checking these points, stop using it and contact us with your concern.

2. Wegovy pen not injecting / no dose delivered

Sometimes patients report that the Wegovy pen did not release the dose even though the button was pressed.

• Confirm the needle is securely attached.
• Check that the safety cap has been removed.
• Make sure the pen was held firmly against the skin throughout the injection.
• Keep holding the button for at least 10 seconds to ensure full dose delivery.
  

If no liquid seems to have entered or you’re unsure if the dose was received, do not attempt a second injection. Contact us for guidance.

3. Air bubbles in the Wegovy pen

Air bubbles are usually harmless but can cause misdelivery if large.

• Small bubbles: Safe and expected; inject as normal.
• Large bubbles: Contact Batley Pharmacy for advice, as the dose volume may be compromised.

Clinical studies confirm that small air bubbles in semaglutide pens do not affect efficacy or safety.

4. Leaking Wegovy pen

If you notice liquid leaking:

• Before injection: The pen may be defective; do not use it in this case.
  
• During or after injection: This may mean an incomplete dose. Do not inject again until you have spoken to your pharmacist.

Keep the leaking pen and bring it to the pharmacy so we can investigate.

5. Wegovy pen jammed

If your Wegovy pen locks mid-injection:

• Stop pressing the button.
• Remove the pen from your skin carefully.
• Do not attempt to repair or reuse the device.

Faulty pens should be reported directly for replacement.

Mounjaro Pen Troubleshooting

The Mounjaro pen contains tirzepatide and, like Wegovy, is designed for single-use weekly dosing. If your Mounjaro pen is not working, follow these checks.

1. Mounjaro pen not clicking

For Mounjaro, the audible click signals activation.

• Ensure the gray base cap has been removed completely.
• Press the pen straight onto the skin until it locks.
• If there’s no click, don’t attempt multiple presses. 

2. Mounjaro pen not injecting / no dose delivered

If you suspect no medicine is delivered:

• Check that the activation button is fully pressed.
• Hold the pen against the skin for at least 10 seconds until you hear the second click indicating completion.
• If unsure whether the full dose was given, don’t inject a new pen without clinical advice.

3. Air bubbles in the Mounjaro pen

Like Wegovy, small bubbles are normal. Large or frothy air pockets, however, may indicate improper storage or a manufacturing fault. 

• If you notice significant bubbling, contact us before use.
• Clinical data suggest that small air bubbles do not affect bioavailability. 

4. Leaking Mounjaro pen

A leaking pen may deliver an incomplete dose.

• If leaking before activation, discard the pen safely.
• If leaking after, note the batch number and speak to us or Eli Lilly for possible replacement.

5. Mounjaro pen jammed

Some patients report the Mounjaro pen locks before completing the injection. In this case:

• Do not force it or try to repair it.
• Store it safely and report the issue.
• Bring it to us for assessment.

Storage Problems (Refrigeration and Temperature Exposure)

Both Wegovy and Mounjaro pens are temperature-sensitive medications.

• Refrigeration: Store between 2°C and 8°C.
• Do not freeze: Frozen pens must be discarded.
• Once out of the fridge, pens can be stored at room temperature (below 30°C) for up to 28 days.
• Avoid direct sunlight or leaving pens in hot cars.

Incorrect storage can lead to:

• Crystallisation
• Air bubble formation
• Loss of potency

Expired Wegovy or Mounjaro Pens

Using expired pens can lead to:

• Reduced drug potency
• Inconsistent dosing
• Potential contamination
  

Always check the expiry date on the carton. If expired, do not inject and request a replacement.

Conclusion

When using Wegovy or Mounjaro, faulty pens are uncommon but can happen. The key steps are:

• Do not reuse or force a faulty pen
• Check storage and handling instructions carefully
• Contact us immediately for support and replacement
• Do not double-dose without clinical advice
  

Batley Pharmacy ensures that every patient receives comprehensive device training, safety advice, and prompt troubleshooting support. If you experience any issues, please book a consultation or call us directly so we can assist you in continuing your treatment safely.

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