52 citations
,
  February 2005   in “Biopolymers”    Chemical hair straightening changes hair proteins and mostly fixes broken bonds.  
      45 citations
,
  December 2006   in “Biopolymers”
           45 citations
,
  December 2006   in “Biopolymers”    Permanent waving weakens hair by altering its protein structure.  
      25 citations
,
  May 2019   in “Heliyon”
           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”
           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.