title: Skin physiology in men and women: in vivo evaluation of 300 people including TEWL, SC hydration, sebum content and skin surface pH.
abstract: OBJECTIVE
  Evidence is given that differences in skin physiological properties exist between men and women. However, despite an assessable number of available publications, the results are still inconsistent. Therefore, the aim of this clinical study is the first systematic assessment of gender-related differences in skin physiology in men and women, with a special focus on changes over lifetime.
  
  
  METHODS
  A total of 300 healthy male and female subjects (20-74 years) were selected following strict criteria including age, sun behaviour or smoking habits. TEWL, hydration level, sebum production and pH value were measured with worldwide-acknowledged biophysical measuring methods at forehead, cheek, neck, volar forearm and dorsum of hand.
  
  
  RESULTS
  Until the age of 50 men's TEWL is significantly lower than the water loss of women of the same age, regardless of the location. With ageing gender-related differences in TEWL assimilate. Young men show higher SC hydration in comparison with women. But, whereas SC hydration is stable or even increasing in women over lifetime, the skin hydration in men is progressively decreasing, beginning at the age of 40. Sebum production in male skin is always higher and stays stable with increasing age, whereas sebum production in women progressively decreases over lifetime. Across all localizations and age groups, the pH value in men is below 5, the pH value of female subjects is, aside from limited expectations, higher than 5.
  
  
  CONCLUSIONS
  Skin physiological distinctions between the sexes exist and are particularly remarkable with regard to sebum production and pH value.
authors.affiliation: Division of Cosmetic Science, Department of Biochemistry and Molecular Biology, University of Hamburg, Martin-Luther-King- Platz 6, 20146, Hamburg, Germany.
authors.forename: S
authors.initials: S
authors.lastname: Luebberding
authors.forename: N
authors.initials: N
authors.lastname: Krueger
authors.forename: M
authors.initials: M
authors.lastname: Kerscher
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D015331:Cohort Studies; D005260:Female; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008297:Male; D008875:Middle Aged; D012629:Sebum / Q000737:chemistry; D012737:Sex Factors; D012879:Skin Physiological Phenomena; D018709:Statistics, Nonparametric; D014870:Water Loss, Insensible / Q000502:physiology; D055815:Young Adult
keywords: biophysical measuring methods; corneometry; evaporimetry, male skin; pH-metry; sebumetry; skin aging; skin barrier; skin physiology/structure