Abstract
Hair styling by heat treatment with a hair iron or curling iron has been frequently done. However, heat treatment causes much hair damage. In this work, we have studied heat damage and how to indicate heat damage. The change of cystine into lanthionine moieties of hair protein occurs with heat treatment. So, we checked whether the amount of lanthionine in hair could serve as an effective heat damage index. As a result, while the amount of cysteic acid was increased by bleach treatment and permanent treatment, the amount of lanthionine was increased by heat treatment. Additionally, we found the degradation of both moisturizing effect and physical strength of hair. Based on these, we concluded that the measurement of lanthionine in the hair was effective to indicate the heat damage to hair.
