Dude I got the stuff you have, Humatrope cartridges. You don't need a pen. I inject the water they give you into the cartridge. Let it sit for and hour in the fridge. It takes a little while for the disk to fully disolve. Then take a 3cc syringe, draw it out and put the GH in a 5ml vial very slowly. Done this three times so far, it works. Be careful and take it slow. BTW, it must be in the fridge at all times.