Cyanocobalamin is a man-made form of vitamin B12 used to treat low levels (deficiency) of this vitamin. Vitamin B12 helps your body use fat and carbohydrates for energy and make new protein. It is also important for normal blood, cells, and nerves. Vitamin B12 injections are usually for people with bodies that have problems absorbing vitamin B12 and those who have undergone gastric surgery or patient's on GLP-1s.