The Human Skin as a Hormone Target and an Endocrine Gland
 January 2004   
in “
 Hormones 
”
 
    androgens  testosterone  5a-dihydrotestosterone  5a-DHT  ACTH  anagen phase  IGF-I  sebocyte proliferation  hair follicle growth  PTHrP  CRH  urocortin  POMC peptides  prolactin  catecholamines  steroid hormones  retinoids  vitamin D  eicosanoids  DHT  insulin-like growth factor 1  adrenocorticotropic hormone  parathyroid hormone-related protein  corticotropin-releasing hormone  pro-opiomelanocortin peptides   
    
   TLDR  Human skin acts like a hormone-producing organ, making and managing various hormones important for skin and hair health.   
  The 2004 study "The human skin as a hormone target and an endocrine gland" concluded that human skin is the largest peripheral endocrine organ. The research found that skin cells produce, release, activate, inactivate, and eliminate hormones, interacting with high-affinity receptors for various hormones. The skin also converts circulating androgens into testosterone and 5a-dihydrotestosterone (5a-DHT). The study also detailed the role of various hormones and compounds in skin and hair health. For instance, overproduction of ACTH may prolong the anagen phase of the hair cycle, and IGF-I significantly stimulates sebocyte proliferation and is essential for hair follicle growth. The document also discussed the synthesis of hormones in the skin, including PTHrP, CRH and urocortin, POMC peptides, prolactin, catecholamines, IGF-I, steroid hormones, retinoids, vitamin D, and eicosanoids. The skin's ability to activate or inactivate these hormones was also discussed.
    
   
   
   
  