Vitamin K is an essential vitamin that aids in blood clotting and healthy bones. It exists in two forms, K-1 and K-2. Vitamin K-1 is the main form and comes primarily from green vegetables. Vitamin K-2 occurs in animal proteins and fermented foods. Bacteria in the human gut also produce small amounts of K-2. This article discusses vitamin K-2, its functions, and how it differs from K-1. It also outlines food sources, health benefits, recommended daily intake, deficiency symptoms, and how to supplement.