Vitamin K is an essential nutrient that plays a critical role in blood clotting, wound healing, and bone health. People who don’t have enough vitamin K in their system are at greater risk of increased bleeding and bone fractures. While the body can produce a small amount of vitamin K, it’s important to obtain it through other sources, too.

Vitamin K is fat-soluble vitamin that plays a role in blood clotting in the body. It comes in two forms: vitamin K1 (phylloquinone) and vitamin K2 (menaquinones). Both have a similar chemical structure of 2-methyl-1,4-naphthoquinone. Vitamin K1 is naturally found in some foods, such as green vegetables like collard greens, spinach, and broccoli.

Vitamin K is a fat-soluble vitamin, so your body stores it in fat tissue and the liver. It is best known for its role in helping blood clot, or coagulate, properly. The "K" comes from its German name, Koagulationsvitamin. Vitamin K also plays an important role in bone health. It is rare to have a vitamin K deficiency.

Vitamin K is found throughout the body including the liver, brain, heart, pancreas, and bone. It is broken down very quickly and excreted in urine or stool. Because of this, it rarely reaches toxic levels in the body even with high intakes, as may sometimes occur with other fat-soluble vitamins.

Vitamin K is present in the liver and other body tissues, including the brain, heart, pancreas, and bone [ 2, 3, 11 ]. In the circulation, vitamin K is carried mainly in lipoproteins [ 2 ]. Compared to the other fat-soluble vitamins, very small amounts of vitamin K circulate in the blood. Vitamin K is rapidly metabolized and excreted.