Relationships between hair growth rate and morphological parameters of human straight hair: a same law above ethnical origins?

After measurement of individual growth rates, natural hair fibres from Asian and Caucasian subjects were analysed using scanning electron microscopy. In total, more than 1000 hairs were analysed. Measurements of diameter, medulla and interscale distance (average distance between two successive cuticle scales) show these parameters strongly correlated with hair growth rate.

Resistance of human hair cuticle after a shaking process in wet conditions: comparison between Chinese and Caucasian hair.

Hair cuticle is the first protection shield of hair against external aggressions such as daily combing or brushing that induce friction, mechanical stress leading to ageing process. The identification of alterations of the hair surface induced by shaking process of various hair fibres, such as virgin and chemically treated Chinese and Caucasian hair, sheds some light on some specific features, e.g.

Challenging the scalp with 'dry' wash shampooing (DW) on Chinese men: an in vivo study.

Cosmetic habits show a strong diversity worldwide. The same applies to procedures that are considered as basic hygiene acts such as shampooing. Apart from common traditional shampoo routine, a special shampoo procedure, 'dry' wash is daily performed in Chinese hair salons.

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.