Vitamin B12 Injections Philadelphia Medical Group Seeing Red: Do B12 Injections Work? LAmag Deficiencies in vitamin B12 and folate can often have overlapping symptoms, and serum levels of these nutrients aren't all that accurate when making a diagnosis. People with B12 deficiency can experience neurological More blood results (prior to b12 injections) : r B12_Deficiency How Long Does It Take to Recover from Vitamin B12 Deficiency? How Long Does a Vitamin B12 Shot Last? Effects and Factors