If your B12 deficiency is due to an autoimmune disease or something that's not related to diet, you may need to get injections every two or three months for the rest of your life
Starting low and adjusting based on results and tolerance is the recommended approach
Long-term use of proton pump inhibitors and metformin can impair B12 absorption, necessitating monitoring or parenteral therapy
Significant main effects of treatment group (prior to BenjaminiHochberg correction since none were significant after correction, although the necessity of correction for multiple comparisons in exploratory analyses remains unresolved 49 ) were observed for the unclassified group and ten classified genera, namely, Acetatifactor , Akkermansia , Erysipelatoclostridium , [ Eubacterium ] coprostanoligenes group , Family XIII UCG-001 , Lactobacillus , Parasutterella , Ruminiclostridium 6 , Ruminococcaceae UCG-004 , and Ruminococcaceae UCG-009
Therefore, serum B 12 values above the cut-off point of deficiency do not necessarily confirm adequate B 12 status