I used to get B12 shots, not sure the dosage but within the hour, I felt a heightened sense of well being and energy. My dr. told me the recommended amount was 1 injection a month.
The normal range of Vitamin B12 is from160-950pg/ml. Reason for such wide range is due to Vitamin B12 is in our tissues plus in the blood so it is difficult to have a true reading. There is a factor in our stomach that we need for Vitamin B12 to work. If that is not present, pernicious anemia occurs and we become vitamin B12 deficient. Supplementation is used for mild vitamin B12 deficiency, such as, with chronic alcoholism, therapy for gastric acid inhibitors, vegan vegetarians, autoimmune disorders, or dementia. Vitamin B12 shots are the best method of treatment and normal treatment is once a month. Your blood levels are monitored while you are receiving injections. Some people have low vitamin B12 levels due to folate deficiency. You did not mention your folate levels. There are no adverse effects associated with Vitamin B12 intake from food and/ or supplementation. If you are really concerned then Vitamin B12 can be easily consumed from our diet. One egg a day (yes, it does have cholesterol, however, it is the good cholesterol our body needs), ½ chicken breast, and 1 cup low fat milk, to name a few vitamin B12 sources would help increase the vitamin.