Editing Melanin (section)

== Humans ==
[[File:Albinistic girl papua new guinea.jpg|thumb|[[Albinism in humans|Albinism]] occurs when melanocytes produce little melanin. This albino girl is from [[Papua New Guinea]].]]
In humans, melanin is the primary determinant of [[human skin color|skin color]]. It is also found in hair, the pigmented tissue underlying the [[iris (anatomy)|iris]] of the eye, and the [[stria vascularis of cochlear duct|stria vascularis]] of the [[inner ear]]. In the brain, tissues with melanin include the [[adrenal medulla|medulla]] and pigment-bearing neurons within areas of the [[brainstem]], such as the [[locus coeruleus]]. It also occurs in the [[zona reticularis]] of the [[adrenal gland]].<ref name=":0">{{Cite journal |last=Solano |first=F. |year=2014 |title=Melanins: Skin Pigments and Much More—Types, Structural Models, Biological Functions, and Formation Routes |journal=New Journal of Science |volume=2014 |pages=1–28 |doi=10.1155/2014/498276 |doi-access=free}}</ref>

The melanin in the skin is produced by [[melanocyte]]s, which are found in the [[Stratum germinativum|basal layer]] of the [[epidermis (skin)|epidermis]]. Although, in general, human beings possess a similar concentration of melanocytes in their skin, the melanocytes in some individuals and ethnic groups produce variable amounts of melanin. The ratio of  eumelanin (74%) and pheomelanin (26%) in the epidermis is constant regardless of the degree of pigmentation.<ref name="i034">{{Cite journal |last1=Del Bino |first1=Sandra |last2=Ito |first2=Shosuke |last3=Sok |first3=Juliette |last4=Wakamatsu |first4=Kazumasa |date=2022 |title=5,6-Dihydroxyindole eumelanin content in human skin with varying degrees of constitutive pigmentation |journal=Pigment Cell & Melanoma Research |volume=35 |issue=6 |pages=622–626 |doi=10.1111/pcmr.13062 |issn=1755-1471 |pmc=9804219 |pmid=35933709}}</ref> Some humans have very little or no melanin synthesis in their bodies, a condition known as [[Albinism in humans|albinism]].<ref>{{Cite journal |last1=Cichorek |first1=Mirosława |last2=Wachulska |first2=Małgorzata |last3=Stasiewicz |first3=Aneta |last4=Tymińska |first4=Agata |date=20 February 2013 |title=Skin melanocytes: biology and development |journal=Advances in Dermatology and Allergology |volume=30 |issue=1 |pages=30–41 |doi=10.5114/pdia.2013.33376 |pmc=3834696 |pmid=24278043}}</ref>

Because melanin is an aggregate of smaller component molecules, there are many different types of melanin with different proportions and bonding patterns of these component molecules. Both pheomelanin and eumelanin are found in human skin and hair, but eumelanin is the most abundant melanin in humans, as well as the form most likely to be deficient in albinism.<ref>{{Cite web |title=oculocutaneous albinism |url=https://ghr.nlm.nih.gov/condition/oculocutaneous-albinism |access-date=25 September 2017 |website=Genetics Home Reference |archive-date=17 July 2020 |archive-url=https://web.archive.org/web/20200717051343/https://ghr.nlm.nih.gov/condition/oculocutaneous-albinism |url-status=live }}</ref>