I use a new needle and syringe each time. I just take 45 mcg out of the vial which is 180 mcg. Then return the vial to my refrigerator. It was stressful in the beginning because I had never injected anything before. But I quickly got used to it. I watched a couple YouTube videos and when I next went to the doctor had the nurse practitioner watch me to make sure I was doing it correctly.