PMCID: PMC1863555
But oral Vitamin B12 supplements do have some limitations: Lower Absorption: For individuals with certain health conditions, such as gastrointestinal disorders or those who have undergone bariatric surgery, oral supplements may not be absorbed as effectively as injections
The recommended dietary allowance (RDA) of Vitamin B12 is 2.4 mcg/day, though slightly more is needed by women who are pregnant (2.6mcg) or breastfeeding (2.8mcg)
Common side effects include injection site reactions (burning, pain, swelling, redness), headache, mild diarrhea, and upset stomach
They may ask you to first perform a blood test to check your vitamin levels and recommend an appropriate treatment plan
It is synthesized exclusively by micro-organisms (e.g., Lactobacillus spp ) (LeBlanc et al., 2013), which are also found in the gastrointestinal tract of herbivorous animals, where the synthesis of B12 occurs and the vitamin can be acquired in animal tissues
