Vitamin K is a group of organic nutritional compounds that is naturally found in vegetables, meat, and dairy product and aids in several metabolic functions in the human body, most notably – the synthesis of blood-clotting proteins. Manufacturers of vitamin K include it in dietary supplements that treat or help prevent vitamin K deficiency. Although it is sometimes available as a standalone medication or supplement, vitamin K is more commonly found in pharmaceutical formulations along with other nutritional compounds. Suppliers of vitamin K primarily market it in tablet and capsule forms. The largest manufacturers of vitamin K include Country Life, Amphastar Pharmaceuticals, NattoPharma, Livealth Biopharma, Solgar, Kappa Bioscience, and Pfizer.