2 citations
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September 2010 in “Journal of the Korea Academia-Industrial cooperation Society” This study found that increasing collagen concentration to 2% in permanent wave treatments reduced hair damage but impaired curl formation.
October 2012 in “한국미용학회지” This study suggests that after perm treatments, sufficient application of keratin and ceramide after middle rinsing enhances curl formation while considering hair health.
65 citations
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March 2017 in “Experimental Dermatology” This review discusses the genetic and biological factors influencing hair curliness, revealing strong links to specific protein variations, and reports no new clinical results.
In this research, the author hypothesizes that curly hair is influenced by the contraction of the Arrector Pili muscle, suggesting that its relaxation through specific treatments could potentially modulate hair follicle curvature, but further studies are needed to confirm this mechanism.
January 2013 in “Sen'i Gakkaishi” This study found that microfibrils play a crucial role in shaping permanent waves by thioglycolic acid, and treating damaged hair with hydrolyzed keratin improved both waving efficiency and hair damage.