From April 2026, the manufacturer is introducing a slightly updated version of the Mounjaro KwikPen as part of a planned change. During this transition, you may receive either the current or the updated version in your upcoming treatment deliveries.
What has changed in the new pen?
The updated pen includes small visual and structural updates to help you easily identify when your treatment is complete:
Clearer completion marker: After your fourth and final dose, the plunger will now sit near the very end of the pen window. This makes it clearer that all medication has been administered and the pen is ready to be safely discarded.
Less excess liquid: You may notice less leftover liquid in the pen after your final dose. The small amount of extra liquid previously included for priming (removing air bubbles) has been reduced.
Both the old and new versions of the pen are completely safe to use and are designed to deliver exactly four doses of your prescribed medication.
Why am I missing a dose from my Mounjaro pen? / Why is there no excess medication left?
If you have recently received the updated Mounjaro KwikPen (rolled out starting April 2026), you are not missing a dose. Every pen, regardless of the version, is designed to deliver exactly four doses of your prescribed medication.
Why it looks like there is less liquid:
New Pens: The manufacturer has reduced the amount of excess liquid that was historically included for priming (removing air bubbles). Because of this, the plunger will sit near the end of the pen window after your 4th dose, and there will be very little liquid left.
Old Pens: Older pens contained roughly 3mL of total liquid, with each dose being about 0.6mL. This meant there was a slight amount of excess solution left over after the 4th dose.
Important safety reminders:
The extra liquid in older pens was never intended for use and is not a 5th dose.
The manufacturer strongly advises against attempting to extract more than 4 doses from any single pen, as the excess solution is not calibrated to deliver further doses correctly.
Please do not use the liquid level within the window of the pen as a marker for how many doses are left.