Vitamin K2 belongs to the fat-soluble, i.e. lipophilic vitamins. Chemically, vitamin K2 belongs to a group of quinones. Therefore, it is also called menaquinone. Other common names among experts are K2, menaquinone, menaquinone, menaquinone-4, MK-4, menaquinone-7, MK-7 or menatetrenone. Our body needs vitamin K2 for blood clotting. Vitamin K2 is the cofactor of an enzyme that is crucial for the activation of clotting factors. It is also involved in the further production of protein building blocks that are important for blood plasma, kidneys and bones.