title: Facial skin-lightening benefits of the tetrapeptide Pro-Lys-Glu-Lys on subjects with skin types V-VI living in South Africa.
abstract: BACKGROUND
  Irregular skin pigmentation may be a substantial contributor to the signs of aging and to a person's lack of psychological well-being. Although a large number of skin-lightening agents are available, the opportunity exists to identify more efficacious agents, agents that target alternative biological mechanisms.
  
  
  OBJECTIVE
  To provide clinical evidence of the skin-lightening effect of the tetrapeptide, Pro-Lys-Glu-Lys (PKEK), on subjects with skin types V-VI living in South Africa.
  
  
  METHODS
  Pro-Lys-Glu-Lys was evaluated in a double-blind and vehicle-controlled clinical study using expert grading of digital images by comparing its effects in subjects with skin types V-VI suffering from facial melasma and postinflammatory hyperpigmentation.
  
  
  RESULTS
  This study demonstrated the efficacy of PKEK on subjects with skin types V-VI. On comparing the two treatments, the skin-lightening peptide-containing formulation was significantly superior to the vehicle at 12 weeks on overall appearance (P < 0.05) and evenness of skin tone (P < 0.01).
  
  
  CONCLUSIONS
  The tetrapeptide, PKEK, has proven skin-lightening benefits on skin discoloration from melasma and postinflammatory hyperpigmentation. These studies have been conducted on subjects with skin types V-VI living in South Africa, but we believe this technology to be suitable for all racial groups.
authors: Evonik Goldschmidt GmbH, Essen, Germany. mike.farwick@evonik.com
authors: Mike
authors: M
authors: Farwick
authors: Ursula
authors: U
authors: Maczkiewitz
authors: Peter
authors: P
authors: Lersch
authors: Beverley
authors: B
authors: Summers
authors: Anthony V
authors: AV
authors: Rawlings
mesh_terms: D000328:Adult; D003879:Dermatologic Agents / Q000627:therapeutic use*; D004311:Double-Blind Method; D005145:Face; D005260:Female; D018698:Glutamic Acid / Q000008:administration & dosage; D006801:Humans; D008239:Lysine / Q000008:administration & dosage; D008548:Melanosis / Q000188:drug therapy*; D008875:Middle Aged; D009842:Oligopeptides / Q000627:therapeutic use*; D011392:Proline / Q000008:administration & dosage; D012880:Skin Pigmentation / Q000187:drug effects; D013019:South Africa; D016896:Treatment Outcome
chemical_list: D003879:Dermatologic Agents; D009842:Oligopeptides; C569858:prolyl-lysyl-glutamyl-lysine; D018698:Glutamic Acid; D011392:Proline; D008239:Lysine