Vitamin K is a fat-soluble vitamin that accumulates in the liver. Its half-life is 1-2 days.

Leafy green vegetables contain vitamin K1, commonly known as phylloquinone. Menaquinone, or vitamin K2, is present in animal products such as cheese and eggs.

Vitamin K3, also known as menadione, is a man-made version of Vitamin K that does not exist in nature. Another synthetic version of Vitamin K is menadiol diacetate, generally known as vitamin K4.