Effect of Shampoo, Conditioner, and Permanent Waving on the Molecular Structure of Human Hair

The study investigated the impact of shampoo, conditioner, and permanent waving on the molecular structure of human hair using X-ray diffraction. It was found that shampoo and conditioner did not affect the packing of keratin molecules, the structure of intermediate filaments, or the internal lipid composition of the membrane complex. However, a single application of a perming product significantly altered the hair's molecular structure by reducing the number of keratin coiled-coils and changing the structure of the intermediate filaments, evidenced by decreased signals at 5 and 9.5 Å and an elevated signal at 47 Å, indicating the breaking of bonds between coiled-coil keratin dimers.