Abstract: A wrinkle-preventing and -improving composition comprising one or more than one compound selected from the group consisting of ?-amino acid derivatives represented by the following general formula (1) and salts thereof: wherein, R1 represents hydrogen atom, CH3 group or CH2OH group, R2 and R3 each independently represent hydrogen atom, alkyl group having 1 to 4 carbons, provided that R2 and R3 cannot be hydrogen atom at the same time, or R2 and R3 together with N atom to which they are bound may form a ring structure having a total carbon number of 4 to 6, in which case said ring structure may optionally contain an oxygen atom as a heteroatom, R4 represents hydrogen atom, alkyl group having 1 to 18 carbons, wherein when R1 and R4 are hydrogen atom, it cannot be that one of R2 and R3 is benzyloxycarbonyl group and the other is hydrogen atom.