PROBLEM TO BE SOLVED: To provide a hair cosmetic which improves the further excellent elasticity of the hair even if comparing with a hair elasticity improver, and imparts a good usability (tension and sturdiness, smoothness and no stickiness).SOLUTION: The invention provides a hair elasticity improver consisting of an arginine derivative obtained by reacting arginine and glycidyl ether which has a straight lined or branched alkyl group, alkenyl group, or hydroxyalkyl group with carbon numbers 1-4, and a hair cosmetic containing the hair elasticity improver.COPYRIGHT: (C)2015,JPO&INPIT【課題】毛髪弾力性向上剤と比較してもさらに優れた毛髪の弾力性を改善し、良好な使用性(ハリ・コシ感、滑らかさ、ベタツキ感の無さ)を付与する毛髪化粧料の提供。【解決手段】アルギニンと直鎖又は分岐した炭素数1~4のアルキル基、アルケニル基もしくはヒドロキシアルキル基を有するグリシジルエーテルとを反応させることにより得られるアルギニン誘導体からなる毛髪弾力性向上剤および該毛髪弾力性向上剤を含有する毛髪化粧料。【選択図】なし
