@Stevepep, here's an idea: use this new black-and-red pen to finish the leftover solution in the pen. Take the cartridge out of the other pens and put it into this new V4 plastique. Finish the research into my pet cobra.

This happened to me to with the same gold V4. I have 6 V4s and it only happens to the gold one. I do what Randy recommended and push a little harder.

@ResearchCat Thank you. I didn't think of recalibrating the loaded cartridge. That makes perfect sense.

Hello Everyone!

I am new to the community, and I am starting my pen journey.

Does anyone using injector pens use different vials of peptides in the same pen?

I have one on the way, a new V4, and I was wondering if I could use BPC and GHKCU on the same pen, but with different 3mm vials. I didn't want to spend the money on multiple pens before I get more familiar with the pen.