12 citations
,
June 2011 in “Journal of applied polymer science” L-phenylalanine and hydrolyzed eggwhite protein deeply penetrate human hair.
45 citations
,
December 2006 in “Biopolymers” Permanent waving weakens hair by altering its protein structure.
52 citations
,
February 2005 in “Biopolymers” Chemical hair straightening changes hair proteins and mostly fixes broken bonds.
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.
53 citations
,
March 2006 in “Biopolymers” TTD hair is brittle due to fewer sulfur amino acids and unstable disulfide bonds.