Because human hair is rich in keratin (found in both the outer and core parts of the hair fiber), this protein is added to many hair care products. It is a fibrous protein made up of chains of amino acids in which minerals and vitamins are also present. It makes the hair smoother and brighter thanks to the presence of cysteine, an amino acid present in keratin. For this reason it is particularly suitable for those who tend to have frizzy and dull hair. It performs a restructuring and strengthening action, making the hair more disciplined.