Potential Side Effects of B12 Injections Like any medical intervention, B12 injections can have potential side effects
Standard blood tests can offer one measurement of B12 levels, but a serum or plasma B12 level does not provide any indication of intracellular B12 levels (2)
Inadequate secretion of intrinsic factor, resulting from lesions that destroy the gastric mucosa (which can be caused by ingestion of corrosives, extensive tumors, and conditions associated with gastric atrophy, such as multiple sclerosis, certain endocrine disorders, iron deficiency, and subtotal gastrectomy) Structural lesions leading to vitamin B 12 deficiency, including regional ileitis, ileal reactions, and malignancies Competition for vitamin B 12 by intestinal parasites or bacteria
Intramuscular vs Subcutaneous B12 Injections Intramuscular or Subcutaneous B12 Injection