Question About Blood Backflow Into GHK-Cu Cartridge

[divacat]

I have been using GHK-Cu in my pen for a couple of months without any issues. Today I replaced the cartridge with a new GHK-Cu cartridge. I attached a new Novo Fine Plus disposable needle, primed the pen until all air bubbles were gone, and then injected my usual dose.

After the injection, I noticed there was blood visible on the needle. When I removed the needle, I looked at the cartridge and saw what appeared to be small blood colored particles floating in the solution. I immediately removed the cartridge from the pen and will not be using that particular one further.

I’m trying to understand what may have happened. Did I do something wrong? How can blood or material from outside the cartridge end up inside a sealed cartridge? Is this a known occurrence with injection pens, and what might cause it?

Any information on the mechanism behind this or how to prevent it in the future would be greatly appreciated.

I’ve attached a photo of the cartridge showing the particles I observed after the injection. Prior to use, the solution appeared normal to me.

[ResearchCat]

You probably hit a blood vessel and there was slight vacuum in the vial (assuming you keep it in the fridge) so before you hit the plunger, it drew some blood into the vial. I have had this happen with syringes but not vials(yet.)

Part of the reason i use short needles (4-6mm) is that with syringes or longer needles 8mm+ i hit vessels and get a lot of bruising. Still happens but much less often.