title: Chronological ageing of human hair keratin fibres.
abstract: Examination of very long hair (length > 2.4 m) using a large range of evaluation methods including physical, chemical, biochemical and microscopic techniques has enabled to attain a detailed understanding of natural ageing of human hair keratin fibres. Scrutinizing hair that has undergone little or no oxidative aggression--because of the absence of action of chemical agents such as bleaching or dyeing--from the root to the tip shows the deterioration process, which gradually takes place from the outside to the inside of the hair shaft: first, a progressive abrasion of the cuticle, whilst the cortex structure remains unaltered, is evidenced along a length of roughly 1 m onwards together with constant shine, hydrophobicity and friction characteristics. Further along the fibre, a significant damage to cuticle scales occurs, which correlates well with ceramides and 18-Methyl Eicosanoic Acid (18-MEA) decline, and progressive decrease in keratin-associated protein content. Most physical descriptors of mechanical and optical properties decay significantly. This detailed description of natural ageing of human hair fibres by a fine analysis of hair components and physical parameters in relationship with cosmetic characteristics provides a time-dependent 'damage scale' of human hair, which may help in designing new targeted hair care formulations.
authors.affiliation: L'Oreal Recherche, Clichy, France.
authors.forename: S
authors.initials: S
authors.lastname: Thibaut
authors.forename: E
authors.initials: E
authors.lastname: de Becker
authors.forename: B A
authors.initials: BA
authors.lastname: Bernard
authors.forename: M
authors.initials: M
authors.lastname: Huart
authors.forename: F
authors.initials: F
authors.lastname: Fiat
authors.forename: N
authors.initials: N
authors.lastname: Baghdadli
authors.forename: G S
authors.initials: GS
authors.lastname: Luengo
authors.forename: F
authors.initials: F
authors.lastname: Leroy
authors.forename: P
authors.initials: P
authors.lastname: Angevin
authors.forename: A M
authors.initials: AM
authors.lastname: Kermoal
authors.forename: S
authors.initials: S
authors.lastname: Muller
authors.forename: M
authors.initials: M
authors.lastname: Peron
authors.forename: G
authors.initials: G
authors.lastname: Provot
authors.forename: S
authors.initials: S
authors.lastname: Kravtchenko
authors.forename: D
authors.initials: D
authors.lastname: Saint-Léger
authors.forename: G
authors.initials: G
authors.lastname: Desbois
authors.forename: L
authors.initials: L
authors.lastname: Gauchet
authors.forename: K
authors.initials: K
authors.lastname: Nowbuth
authors.forename: A
authors.initials: A
authors.lastname: Galliano
authors.forename: J Y
authors.initials: JY
authors.lastname: Kempf
authors.forename: I
authors.initials: I
authors.lastname: Silberzan
mesh_terms: D000328:Adult; D044466:Asian People; D002518:Ceramides / Q000032:analysis*; D004537:Eicosanoic Acids / Q000032:analysis*; D015180:Electrophoresis, Gel, Two-Dimensional; D005260:Female; D006197:Hair / Q000737:chemistry* / Q000648:ultrastructure; D006801:Humans; D053564:Keratins, Hair-Specific / Q000737:chemistry*; D018625:Microscopy, Atomic Force; D008855:Microscopy, Electron, Scanning; D046529:Microscopy, Electron, Transmission; D021241:Spectrometry, Mass, Electrospray Ionization; D013500:Surface Tension
chemical_list: D002518:Ceramides; D004537:Eicosanoic Acids; D053564:Keratins, Hair-Specific; C111345:18-methyleicosanoic acid