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.
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.
3 citations,
April 2011 in “Microscopy research and technique” Teratoma hair is similar to scalp hair but has a rougher surface and lower adhesive force.