PubMed Central, Wang, Honglei, et al
[1] Because intrinsic-factor-dependent uptake in the distal ileum can be absent in conditions such as autoimmune gastritis, pancreatic insufficiency, or bariatric surgery, the intramuscular or subcutaneous route bypasses gastrointestinal barriers and reliably restores serum concentrations
Avoid sodium azide when it may interfere with downstream applications, especially cell-based assays
Brit Mollenhauer, Paracelsus-Elena-Klinik, Kassel, Germany
As we get older, the stomach tends to make less acid, and that cuts down on how much B12 you can draw from the food you eat
You should talk to your doctor about the dosage is right for you in this case