Vitamin B12 , also called cobalamin, is a water-soluble vitamin that plays a key role in the normal functioning of the brain, nervous system, and red blood cell formation. It is one of the eight B vitamins. It is involved in the metabolism of every cell in the human body, especially affecting the synthesis and regulation of DNA, but also in the metabolism of fatty acids and amino acids. Directions for use: 1 or 2 ml directly into the mouth. You can also mix it in a glass of water or juice, but never mix it with hot drinks. Follow your healthcare professional's recommendations. Shake well before use.