title: Protection effect of cosmetics on human skin under simulated rigorous environment.
abstract: OBJECTIVE
  The efficacy of cosmetics on human skin measured under normal mild laboratory environment might be discounted by exterior environment factors such as wind, UV exposure, etc. Few studies have focused on the 'genuine' efficacy of cosmetics on human skin during exposure to external rigorous environment. The aim of this study was to develop a model for the evaluation of the efficacy of cosmetics on human skin under simulated rigorous environment.
  
  
  METHODS
  We measured skin water content and transepidermal water loss (TEWL) before and after products application under simulated windy and sub-erythema UV exposure treatment in a constant temperature and humidity laboratory.
  
  
  RESULTS
  The results showed that the products had higher water content and lower TEWL at 2, 4 and 8 h of products application, and ameliorated the skin moisturization situation after a 3-week continuous use of the products. In addition, the products might protect the skin to maintain the normal water content and TEWL under the simulated windy or sub-erythema UV exposure treatment in our laboratory when compared with untreated area.
  
  
  CONCLUSIONS
  Our data indicate that this model may provide a more accurate evaluation for the genuine moisturizing effect of cosmetics under external natural climate.
authors.affiliation: Beijing Sino-German Union Cosmetic Institute Co, Chinese Academy of Inspection and Quarantine, Beijing, China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Cheng
authors.forename: Yi-Yang
authors.initials: YY
authors.lastname: Dong
authors.forename: Mei-Xian
authors.initials: MX
authors.lastname: Dong
authors.forename: Chao
authors.initials: C
authors.lastname: Wang
authors.forename: Ning
authors.initials: N
authors.lastname: Su
authors.forename: Yuan-Tao
authors.initials: YT
authors.lastname: Sun
authors.forename: Juan
authors.initials: J
authors.lastname: Liu
authors.forename: Hong-Yan
authors.initials: HY
authors.lastname: Zheng
authors.forename: Andreas
authors.initials: A
authors.lastname: Schrader
authors.forename: Mathias
authors.initials: M
authors.lastname: Rohr
authors.forename: Wei
authors.initials: W
authors.lastname: Liu
mesh_terms: D000328:Adult; D002610:Cheek / Q000502:physiology; D003358:Cosmetics / Q000493:pharmacokinetics / Q000494:pharmacology*; D025802:Electric Capacitance; D004643:Emollients / Q000493:pharmacokinetics / Q000494:pharmacology*; D004780:Environment, Controlled; D005260:Female; D005542:Forearm / Q000502:physiology; D006801:Humans; D012867:Skin / Q000187:drug effects* / Q000528:radiation effects; D012879:Skin Physiological Phenomena; D014466:Ultraviolet Rays; D014870:Water Loss, Insensible; D014919:Wind
chemical_list: D003358:Cosmetics; D004643:Emollients