(19) Gastric surgeries: If a portion of your stomach has been removed, the body cant produce enough IF, and the amount of space for B12 to be absorbed is also reduced
Availability & Jurisdictional Variation In the United States, 5-Amino-1MQ may be purchased legally only for laboratory research
This depends on your goals and B12 levels

Vitamin B12 shot may be prescribed to prevent or treat the following: Pernicious anemia (a condition in which there are low red blood cell counts due to an abnormality in B12 absorption by the intestines) Megaloblastic anemia (a type of anemia in which there are very large red blood cells called megaloblasts) Cognitive disorders, such as dementia (a disorder characterized by problems with memory, problem-solving abilities, language, etc.) Disorders that affect B12 absorption, such as pancreatic diseases, intestinal infections, Crohns disease, and tropical sprue Cardiovascular disease risk (by lowering blood homocysteine levels, which is a compound associated with an increased risk of heart problems) Multiple sclerosis symptoms Bells palsy recovery B12 deficiencies related to: Weight loss Vegan or restrictive diets Surgery to remove the part of the stomach or the ileum (the last part of the small intestine) Energy and endurance What are signs of vitamin B12 deficiency

Pediatric (FDA) Other brands Nephplex Rx, Nephrocaps, Reno Caps, Dotremin,
In rare cases, some people might have severe side effects like: Skin rash, itching, or hives Swelling of the face, lips, or tongue Chest pain or tightness Blue tint to the skin Difficulty breathing or wheezing A swollen, painful area on the leg Dizziness If you experience any of the above side effects, reach out to a healthcare provider immediately