Once you have a b12 deficiency and take monthly injections, will that be the case for the rest of your life or will you be able to stop injections?

B12 deficiency: Unfortunately, you will need to take B12 lifelong. To stop would put you at risk for anemia and severe neurologic problems like neuropathy, difficulty with balance and walking, "megaloblastic madness", and death. Sometimes, patients can take high doses of vitamin B12 1-2 mg orally once daily instead of the shots. Ask your doctor if this is possible for you.