A method for perming or coloring hair, in which hair is treated with a cosmetic composition including a protein-glutaminase and not including an alkaline substance. A method of enhancing hair-permeation of an active ingredient included in a cosmetic composition, in which a protein glutaminase is included in the cosmetic composition. The cosmetic composition does not include an alkaline substance, and the active ingredient is at least one of a hair perm agent and a hair coloring agent.
