research Enzymatic approach to analyze the effects of mercaptans on hair May 2010 in “International Journal of Cosmetic Science” Mercaptans make hair more prone to damage, with reduced hair being more affected than permed hair.
research Strategies for improved hair binding: Keratin fractions and the impact of cationic substructures 8 citations , May 2020 in “International journal of biological macromolecules” Certain treatments can increase protein binding to natural hair but are less effective on permed hair.