title: Does D matter? The role of vitamin D in hair disorders and hair follicle cycling.
abstract: BACKGROUND
  The role of vitamin D in the proliferation and differentiation of keratinocytes is well known within the field of dermatology.
  
  
  OBJECTIVE
  We sought to evaluate the role that vitamin D and the vitamin D receptor play in the hair cycle and assess how this can be clinically applied to the treatment of hair disorders.
  
  
  METHODS
  A MEDLINE search (1955-July 2009) was preformed to find relevant articles pertaining to vitamin D, the vitamin D receptor, and hair loss.
  
  
  RESULTS
  The vitamin D receptor, independent of vitamin D, plays an important role in hair cycling, specifically anagen initiation. The role of vitamin D in hair follicle cycling is not as well understood.
  
  
  CONCLUSIONS
  The review is broad and there are limited human studies available to date.
  
  
  CONCLUSIONS
  Additional studies to evaluate the role of vitamin D in the hair cycle should be done. Treatments that up regulate the vitamin D receptor may be successful in treating hair disorders and are a potential area of further study.
authors.affiliation: Department of Dermatology, University of Texas and MD Anderson Cancer Center, Houston, Texas, USA. rashidrashid.mdphd@yahoo.com
authors.forename: Karrie T
authors.initials: KT
authors.lastname: Amor
authors.forename: Rashid M
authors.initials: RM
authors.lastname: Rashid
authors.forename: Paradi
authors.initials: P
authors.lastname: Mirmirani
mesh_terms: D000505:Alopecia / Q000235:genetics; D000818:Animals; D006197:Hair / Q000187:drug effects / Q000196:embryology / Q000254:growth & development; D006201:Hair Diseases / Q000188:drug therapy*; D018859:Hair Follicle / Q000502:physiology*; D006801:Humans; D051379:Mice; D018345:Mice, Knockout; D009154:Mutation; D018167:Receptors, Calcitriol / Q000235:genetics / Q000378:metabolism*; D047488:Retinoid X Receptors / Q000235:genetics; D015398:Signal Transduction; D014157:Transcription Factors / Q000235:genetics; D014807:Vitamin D / Q000378:metabolism* / Q000494:pharmacology / Q000627:therapeutic use*; D051153:Wnt Proteins / Q000378:metabolism
chemical_list: C490267:HR protein, human; D018167:Receptors, Calcitriol; D047488:Retinoid X Receptors; D014157:Transcription Factors; D051153:Wnt Proteins; D014807:Vitamin D