Vitamin K is a name given to a group of fat-soluble vitamins. They are considered essential cofactors in humans for the production of several proteins that are involved in coagulation homeostasis and calcium homeostasis. The original term vitamin “K” comes from the K in the Germanic word Koagulation meaning the ability to clot blood or prevent hemorrhage. Much has been learned about vitamin K and its role in osteoporosis, vascular calcification, osteoarthritis, cancer, and cognition over the past few years. The most commonly known vitamin K types are listed in below along with their corresponding functions and sources.