Vitamin K1 – naturally found in green leafy vegetables
Vitamin K2 – produced by bacteria living inside a dog’s gut
Vitamin K3 – menadione, chemical synthetic

Vitamins K1 and K2 are considered natural and fat soluble. So, they’re chemically ready to be used by the body just as they are.

However, [URL="http://www.yameiaspartame.com/products/menadione-vitamin-k3/"]vitamin K3[/URL] is synthetic. And all forms of the chemical must first undergo the cellular process of alkylation before they can be used by the body.