Permanent waving is very popular in Japan. Polypeptide chains (main chains) form the principal components of hair, and they are lined up longitudinally. Hair relaxation is also called straight permanent waving, and there are methods that change curly or wavy hair into straight hair. Hair damage as a result of winding, combing, and using high-temperature hairdressing irons is also often seen. By using scanning electron micrographs (SEM) we showed broken hairs and hair damage caused by permanent wave solutions. The hair damage is obvious when comparisons are made with the condition of the hair surface, condition of the cuticle, etc. Hair swelling by permanent wave solutions, manipulations such as winding, etc., inadequate rinsing with water, procedures on injured hair at the outset, etc., are considered possible reasons for any of these types of injury.
 M. O. Han, J. A. Chun, J. W. Lee and C. H. Chung, “Effects of Permanent Waving on Changes of Protein and Physicomorphological Properties in Human Hair,” Journal of Cosmetic Science, Vol. 59, No. 3, 2008, pp. 203-215.
 Z. Wang, X. Ren, D. Wang, Y. Guan and L. Xeia, “Effects of Thioglycolic Acid on Parthenogenetic Activation of Xenopus Oocytes,” PLos One, Vol. 6, 2011, Article ID: e16220. doi:10.1371/ journal.pone.0016220
 K. Suzuta, S. Ogawa, Y. Takeda and K. Kaneyama, “Intermolecular Disulfide Cross-Linked Structural Changes Induced by Permanent Wave Treatment of Human Hair with Thioglycolic Acid,” Journal of Cosmetic Science, Vol. 63, No. 2, 2012, pp. 177-196.
 Y. Lee, Y. D. Kim, H. J. Hyun, L. Pi, X. Jin and W. S. Lee, “Hair Shaft Damage from Heat and Drying Time of Hair Dryer,” Annals of Dermatology, Vol. 23, No. 4, 2011, pp. 455-462. doi:10.5021/ ad.2011.23.4.455