Chronological ageing of human hair keratin fibres.
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.
Thibaut
S
S
L'Oreal Recherche, Clichy, France.
de Becker
E
E
Bernard
B A
BA
Huart
M
M
Fiat
F
F
Baghdadli
N
N
Luengo
G S
GS
Leroy
F
F
Angevin
P
P
Kermoal
A M
AM
Muller
S
S
Peron
M
M
Provot
G
G
Kravtchenko
S
S
Saint-Léger
D
D
Desbois
G
G
Gauchet
L
L
Nowbuth
K
K
Galliano
A
A
Kempf
J Y
JY
Silberzan
I
I
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
D002518:Ceramides; D004537:Eicosanoic Acids; D053564:Keratins, Hair-Specific; C111345:18-methyleicosanoic acid