title: Protective effect of conditioning agents on Afro-ethnic hair chemically treated with thioglycolate-based straightening emulsion.
abstract: Straightening is a chemical process by which excessively curly hair is straightened in an irreversible way. Generally, products are formulated as emulsions with high pH value (9.0-12.0), which, after applied on hair, cause considerable damage, making it dry and fragile. This research work evaluated the protective effect of lauryl PEG/PPG-18/18 methicone, cyclopentasiloxane (and) PEG-12 dimethicone cross-polymer, jojoba oil, and aqua (and) cystine bis-PG propyl silanetriol, as conditioning agents, on Afro-ethnic hair locks treated with thioglycolate-based straightening emulsions by protein loss, combability, and traction to rupture. Standard Afro-ethnic hair locks were prepared following a protocol for straightening emulsion application. Considering the assays performed, the addition of conditioning agents to the straightening emulsion with ammonium thioglycolate benefited the hair fiber, thus diminishing protein loss, protecting the hair thread, and improving resistance to breakage. Jojoba oil and lauryl PEG/PPG-18/18 methicone were the conditioning agents that presented the best results. Straightening emulsions with ammonium thioglycolate containing aqua (and) cystine bis-PG propyl silanetriol and cyclopentasiloxane (and) PEG-12 dimethicone cross-polymer were the ones that provided higher breakage resistance of the thread.
authors.affiliation: Department of Pharmacy, School of Pharmaceutical Sciences, University of São Paulo, São Paulo, SP, Brazil.
authors.forename: Tania Cristina de Sá
authors.initials: TC
authors.lastname: Dias
authors.forename: André Rolim
authors.initials: AR
authors.lastname: Baby
authors.forename: Telma Mary
authors.initials: TM
authors.lastname: Kaneko
authors.forename: Maria Valéria Robles
authors.initials: MV
authors.lastname: Velasco
mesh_terms: D001696:Biomechanical Phenomena; D044383:Black People; D003358:Cosmetics / Q000494:pharmacology*; D004129:Dimethylpolysiloxanes / Q000494:pharmacology; D004643:Emollients / Q000494:pharmacology*; D045703:Emulsifying Agents / Q000494:pharmacology; D004655:Emulsions; D006018:Glycols / Q000494:pharmacology; D006197:Hair / Q000187:drug effects* / Q000378:metabolism / Q000502:physiology; D006203:Hair Preparations / Q000494:pharmacology*; D006801:Humans; D011506:Proteins / Q000032:analysis; D012821:Silanes / Q000494:pharmacology; D012828:Silicones / Q000494:pharmacology; D013864:Thioglycolates / Q000494:pharmacology*; D014885:Waxes / Q000494:pharmacology
chemical_list: D003358:Cosmetics; D004129:Dimethylpolysiloxanes; D004643:Emollients; D045703:Emulsifying Agents; D004655:Emulsions; D006018:Glycols; D006203:Hair Preparations; D011506:Proteins; D012821:Silanes; D012828:Silicones; D013864:Thioglycolates; D014885:Waxes; C530013:lauryl PEG-PPG-18-18 methicone; C034743:jojoba wax