You get a series of B12 shots, day-in and day-out, as a way to replenish your body with the B12 that it cant absorb through the stomach
Other Studies Joint repair effect: In the rabbit collagenase-induced knee osteoarthritis model, AOD 9604 can promote cartilage regeneration, and the effect is better when combined with hyaluronic acid injection
For many others, high-dose oral B12 works just as well (NIH ODS
Nat Clin Pract Endocrinol Metab

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

However, it is advisable to consult with your doctor to discuss potential risks based on your medical history