November 2022 in “International journal of trichology” This study found that glyoxylic acid caused more protein loss in hair compared to traditional alkaline straighteners, though both types of treatments showed comparable effects on hair tensile strength.
18 citations
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August 2009 in “Skin Research and Technology” In this study, optical coherence tomography was used to produce 3D images of human hair, revealing that after chemical treatment with ammonium thioglycolate, the main hair structures were not identifiable due to damage.
18 citations
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July 2015 in “Journal of cosmetic dermatology” This study observed that combining hair dyeing with sodium hydroxide relaxers drastically increased protein loss in Caucasian virgin dark brown hair, while ammonium thioglycolate or guanidine hydroxide relaxers caused less damage.
March 2010 in “Cosmetic Dermatology” Hair straightening methods have advanced to improve effectiveness and reduce damage, but still rely on heat and chemicals.
1 citations
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November 2011 in “Dermatologica Sinica” This study found a significant decline in serum zinc levels among women of African descent using hair relaxers and experiencing alopecia, with age at first exposure potentially influencing alopecia development.