52 citations,
February 2005 in “Biopolymers” Chemical hair straightening changes hair proteins and mostly fixes broken bonds.
45 citations,
December 2006 in “Biopolymers” Permanent waving weakens hair by altering its protein structure.
42 citations,
January 2011 in “Journal of Biomedical Optics” Infrared and Raman imaging can non-destructively analyze hair structure and help diagnose hair conditions.
25 citations,
May 2019 in “Heliyon” Hair treatments cause significant structural changes, especially with excessive heat, regardless of ethnicity.
20 citations,
December 2012 in “Journal of molecular structure” The study found that thioglycolic acid breaks down hair bonds more consistently than l-cysteine, which is less damaging to hair.