For varying reasons, sometimes our bodies do not get enough Vitamin B12 or are not utilizing the B12 we have. Sometimes illness, sometimes stress, sometimes trama...the list goes on. When a doctor tests for it, generally the test comes back without a Vitamin B12 deficiency. But, the opinion is, this doesn't mean our bodies don't need more depending on what is going on.
So in steps vitamin B12 shots or cyanocobalamin.
The idea with using shots is that B12 saturates into our system with better overall coverage and our body accepts it better. You can take supplements, but they are not absorbed as well.
Vitamin B12 has a lot to to with our over all health, psyche and nervous system. It was found many years ago that some patients in mental institutes presenting with schizophrenia were actually vitamin b12 deficient. This is how serious it can be with a deficiency. Thus far I haven't ran into reports of "overdosing" on vitamin B12. It is excreted through our urine. But I haven't read all the reports, so you may want to check into that also. Let me know if you find something.
I take B12 shots monthly. I've been through some unusually high trama and stress factors and age. So I opted for the shots to see if it would help. I am undecided.
Wanderingherb