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

Abstract

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. Without pre-wetting step, hairdresser applies the shampoo directly to dry hair with small quantity of water to create foam. Hand massaging is then offered on the scalp. This shampooing process is distinguished from traditional 'regular wash' by slightly diluted shampoo, and longer contact with the scalp and scalp massaging, all of which could be possibly considered as challenges to the structure and barrier function of the scalp. In this study, the effects of 'dry' wash on Chinese scalp have been investigated, in vivo, using regular wash as a control. A total of 67 Chinese males in two cohorts, non-dandruff and with dandruff, 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 five consecutive days using the same shampoo formulation. Volunteers' self assessment, clinical assessment by an expert and instrumental measurements were carried out. The results showed that Chinese 'dry' wash did not induce any negative consequence on the scalp physiology under such experimental conditions.

A Comprehensive Pathophysiology of Dandruff and Seborrheic Dermatitis – Towards a More Precise Definition of Scalp Health

“…The barrier is no longer as effective as normal skin at reducing moisture vapor transmission (35) nor is it as effective at reducing the penetration of exogenous materials, such as topical application of a solution containing histamine (36). This impaired barrier fiinction leads to acceleration of the condition progression, likely disposing the skin to be less effective at blocking the penetration of the inflammatory initiators originating from Malassezia metabolic activity.…”

“…As expected, function follows structure and, as the structure improves due to treatment, so does the function of the skin. Barrier structural integrity as assessed by comeosurfammetry improves (37) as does a normalization of TEWL (35).…”

Understanding the dandruff scalp before and after treatment: an in vivo Raman spectroscopic study

“…O'Goshi performed TEWL and surface hydration measurements on scalp skin but on hairless scalp, on subjects with male pattern baldness and with alopecia, and Liu et al . observed higher TEWL through dandruff skin. Laden reported that dandruff flakes have a reduced water‐holding capacity compared with skin samplings from the back of the hand but did not examine skin flakes from non‐dandruff scalp .…”

“…Some studies on scalp skin barrier quality have begun to address this. It has been reported that dandruff scalp skin has higher transepidermal water loss (TEWL) than healthy scalp skin . Also, the level of skin lipids is reduced and ratios between lipid types differ in dandruff skin, and their structural organization is more disorganized .…”

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“…[11] The samples were given by the Pharmaceutical Science and Research Centre "Aliyance Krasoty" (Beauty Alliance, Kyiv, Ukraine). Lactic acid (Lactic Acid, "Galactic," Belgium) was used as a pH adjuster of the foaming base value.…”