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, vitamin K3 is synthetic. And all forms of the chemical must first undergo the cellular process of alkylation before they can be used by the body.