Why does THK Hair Building Fibres add a small quantity of Keratin Derivatives?

Keratin Derivatives are produced by a special process which removes the original biological activity. Therefore, there’s no need to add Bactericide and Preservative. A small amount of Keratin Derivatives enables THK Hair Building Fibres look natural and shiny, very much like real hair. Keratin Derivatives are also the carrier of homopolar negative ions.