Keratin fiber strengthening agent and method for strengthening keratin fiber

摘要

A keratin fiber strengthening agent comprising 0.001 to 20% by weight of at least one (2S,3R)-2-acylaminoalkane-1,3-diol represented by formula (I): wherein R<1> represents a straight-chain alkyl group having 9 to 17 carbon atoms; and R<2> represents an acyl group having 2 to 24 carbon atoms which may contain at least one hydroxy group or unsaturated bond is disclosed. A method for improving physical properties, such as breaking strength, of keratin fiber such as hair comprising applying the keratin fiber strengthening agent to keratin fiber by adhesion, coating or impregnation is also disclosed.