The Effect Of Dry Cleaning On Chinese Scalp

Cosmetic habits show a strong diversity worldwide. The same applies to procedures that are considered as basic hygiene act such as shampooing. The act of shampooing usually follows a common procedure, i.e. applying a few grams of shampoo onto previously wet hair and scalp, followed by hand massage, allowing the foam to quickly develop wherein the emulsification takes place. Some people like to carry out a second similar wash after rinsing the foam to have a better cleansing effect.Apart from this common shampoo routine, a special shampoo procedure "dry wash" is daily performed in Chinese hair salons. Without pre-wetting step, hairdresser applies the shampoo directly to dry hair with small quantity of water to create foam. Hand massaging on scalp is then offered with foam on. This shampoo process is distinguished from traditional "regular wash" by slightly diluted shampoo by longer contact with scalp and scalp massaging, all of which could be possibly considered as challenges to the structure and barrier function of the scalp. However, the lack of evidence of the safety and tolerance of dry wash made a few consumers turned back to regular washes.In this study, the effects of dry wash on Chinese scalp have been investigated, in vivo, using regular wash shampooing as a control. A total of 67 Chinese males in 2 cohorts, non dandruff and dandruff prone, were included. In each cohort, volunteers were split into two groups, one with dry wash and the other one with regular wash. Both shampoo methods were performed daily for 5 consecutive days using the same shampoo formulation. Volunteers’ self assessment, clinical assessment by expert and instrumental evaluation were carried out. The major findings are summarized as follows:<1> On the whole population, there was no significant difference between the 2 shampooing methods at all time points according to results of volunteers’self assessment, clinical assessment and instrumental evaluation. The Chinese dry wash did not induce any negative consequence on the scalp physiology under such experimental conditions.<2> Higher concentration of shampoo, longer contact and deep massage of the human scalp seem therefore of little influence on dandruff prone population. On the contrary, removal of dandruff accompanied by the reparation of scalp’s barrier function was found right after the consecutive shampoo period and after post- treatment. Both of our shampooing methods could help improve the physiological condition on dandruff prone scalp.