Cuticle (hair)
{{short description|Outermost part of a hair}}
file:CSIRO ScienceImage 8115 Human hair and Merino wool fibre.jpg
The hair cuticle is the outermost part of the hair shaft.James, William; Berger, Timothy; Elston, Dirk (2005) Andrews' Diseases of the Skin: Clinical Dermatology (10th ed.). Saunders. Page 8. {{ISBN|0-7216-2921-0}}. It is formed from dead cells, overlapping in layers, which form scales that strengthen and protect the hair shaft.{{cite web |url=http://www.worsleyschool.net/science/files/hair/page.html |title=Hair! |publisher=Worsleyschool.net |date= |accessdate=2016-06-13}}{{cite encyclopedia |title=Hair |encyclopedia=British Medical Association Complete Family Health Encyclopedia |year=1990 |publisher=Dorling Kindersley Limited |location= |id= }} These layers are formed of keratin proteins.{{cite journal |title=Known and Unknown Features of Hair Cuticle Structure: A Brief Review |journal=Cosmetics}} The hair cuticle is also known to contain anteiso-18-methyleicosanoic acid which contribute to the hydrophobic properties of hair. {{cite journal|url=https://pubmed.ncbi.nlm.nih.gov/9519472/|title=The role of 18-methyleicosanoic acid in the structure and formation of mammalian hair fibres|journal=Micron}}
While the cuticle is the outermost layer, it is not responsible for the color of the hair. Melanin is the pigment that gives hair its color and is found in the cortex.{{cite web |url=http://www.keratin.com/aa/aa024.shtml |title=Hair biology - hair fiber |publisher=Keratin.com |date= |accessdate=2013-08-18 |archive-date=2020-08-01 |archive-url=https://web.archive.org/web/20200801091759/https://www.keratin.com/aa/aa024.shtml |url-status=dead }}