Disclosed are: a hair treating agent for forming permanent waves or straightening frizzy hair, which comprises an alkyl ether carboxylic acid amino acid salt represented by general formula (I): R1-O-(CH2CH2O)nCH2COOM (wherein R1 represents a saturated or unsaturated hydrocarbon group n represents a numerical value of 1 to 10 and M represents a lysine residue, a histidine residue or an arginine residue) and a reducing agent a treatment method for forming permanent waves or straightening frizzy hair, which comprises a step of applying the hair treating agent to the whole or a part of hair and a promoter for the penetration into hair, which comprises the alkyl ether carboxylic acid amino acid salt.本發明所揭示的是一種燙髮用或捲縮毛髮矯直用之毛髮處理劑,含有通式(I):R1-O-(CH2CH2O)nCH2COOM (I) (式中,R1表示飽和或不飽和烴基、n表示1~10之數、M表示離胺酸、組胺酸或精胺酸)所表示之烷基醚羧酸胺基酸鹽以及還原劑;一種燙髮或捲縮毛髮矯直處理方法,包含將該毛髮處理劑應用到全部或一部分頭髮之步驟;以及一種毛髮滲透促進劑,含有該烷基醚羧酸胺基酸鹽。(無)
