Hi, Do you have Anemia OR PERNICIOUS ANEMIA?? There is a big difference. My aunt is 86 and has taken monthly Bl2 injections since she was a young girl. The reason I ask is that you mentioned the treatment as both Iron and Bl2. Iron is for Iron-Deficiency-Anemia, and B12 is for Pernicious-Anemia. Perhaps you have both. Read up on both bodily disorders and try to understand them, before you worry about how long they will take to go away.