An object of the present invention is to provide a whitening agent that is effective in preventing and inhibiting melanin pigmentation such as pigmented spot, freckles, and somberness. Specifically, the present invention provides a whitening agent containing at least one D-amino acid selected from the group consisting of D-asparagine, D-valine, D-allo-threonine, D-lysine, D-glutamine, D-histidine, D-leucine, D-phenylalanine, D-serine, D-tryptophan, and D-tyrosine and a method of evaluation of a skin by a D-amino acid.
