title: The long-term use of soap does not affect the pH-maintenance mechanism of human skin.
abstract: BACKGROUND
  The pH at the surface of healthy human skin is around 5. Cleansing the skin with soap increases the pH of the skin, which then returns to a more acidic pH within a few hours. However, the effects of skin cleansing with soap over a long time on the pH regulatory system is still unclear.
  
  
  OBJECTIVE
  We compared the pH of the skin between users of a soap-based cleanser and of a mild-acidic cleanser prior to and following the cleansing.
  
  
  METHODS
  This study had two groups of subjects, one group who had used a soap-based cleanser for more than 5 years and the other group who had used a mild-acidic cleanser for more than 5 years. The pH on the inner forearm of each subject was measured prior to and for 6 h after cleansing with a soap bar.
  
  
  RESULTS
  There were no differences between the pH of the skin these two groups prior to cleansing, immediately after cleansing or in the pH recovery rate for 6 h.
  
  
  CONCLUSIONS
  These results suggest that long-term continuous use of a soap-based cleanser does not affect the pH-maintaining mechanism of human skin.
authors: Kao Corporation, Tokyo, Japan.
authors: Y
authors: Y
authors: Takagi
authors: K
authors: K
authors: Kaneda
authors: M
authors: M
authors: Miyaki
authors: K
authors: K
authors: Matsuo
authors: H
authors: H
authors: Kawada
authors: H
authors: H
authors: Hosokawa
mesh_terms: D000328:Adult; D003902:Detergents / Q000737:chemistry*; D005260:Female; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008137:Longitudinal Studies; D008297:Male; D012867:Skin / Q000737:chemistry* / Q000187:drug effects*; D017592:Skin Care / Q000379:methods*; D012915:Soaps / Q000737:chemistry* / Q000494:pharmacology*; D055815:Young Adult
chemical_list: D003902:Detergents; D012915:Soaps
keywords: cleanser; pH; skin; soap