pheomelanin

noun

pheo·​mel·​a·​nin ˌfē-ə-ˈme-lə-nən 

variants or less commonly phaeomelanin

plural pheomelanins also phaeomelanins

: a reddish-yellow sulfur-containing melanin pigment formed in the presence of cysteine

… in people with dark brown or black hair, the pheomelanin is effectively masked by the darker eumelanin.

—Erin Brodwin

The marked spectrum of color and diversity of patterns … in mammals arises, unexpectedly, from variation in the quantity, quality, and regional distribution of just two types of pigment—black eumelanin and yellow pheomelanin.

—Sophie I. Candille et al.

compare eumelanin, neuromelanin

Examples of pheomelanin in a Sentence

Recent Examples on the Web

With pheomelanin, the red-brown, red-hair melanins being more jellybean-shaped, and the eumelanin being more hot-dog-shaped. —Quanta Magazine, 21 Aug. 2025

Through an unknown mechanism, this change may alter pigment production away from dark eumelanin to lighter pheomelanin – orange. —Grrlscientist, Forbes.com, 2 June 2025

There are two types of hair melanin: pheomelanin, which produces blond and red hair, and eumelanin, which makes darker hair. —Rj MacKenzie, Popular Science, 20 Mar. 2025

No or very little eumelanin or pheomelanin (albinism) tends to produce pale skin/white hair. —Heather Jones, Verywell Health, 1 Aug. 2024

Slater and her colleagues went looking for ginger shades in the fossil record because evidence of pheomelanins has shown up there far less often than the researchers expected, compared with modern-day animals. —Riley Black, Scientific American, 14 Dec. 2023

While eumelanin and pheomelanin control the colors of such visible characteristics, neuromelanin affects neurons in the brain and plays a role in protection against neurodegenerative disorders such as Parkinson's disease. —Daryl Austin, USA TODAY, 1 Sep. 2023

Word History

Etymology

borrowed from German Phäomelanin, from Greek phaiós "a shade between black and white, gray, dark gray" (of obscure origin) + Melanin melanin

Note: The term Phäomelanin was apparently introduced, along with Eumelanin eumelanin, by the biologist Karl Görnitz in "Versuch einer Klassifikation der häufigsten Federfärbungen," Journal für Ornithologie, Band 71 (1923), Heft 1, pp. 127-31. On the meaning of the element phäo-/pheo- see the note at pheochromocytoma.

First Known Use

1924, in the meaning defined above

Rhymes for pheomelanin

• melanin

Medical Definition

pheomelanin

noun

pheo·​mel·​a·​nin

variants also phaeomelanin

ˌfē-ə-ˈmel-ə-nən 

: a reddish-yellow sulfur-containing melanin pigment formed in the presence of cysteine

As pH reduces, there is a progressive reduction in tyrosinase activity leading to increased pheomelanin and reddish or blonde hair.

—Anagha Kumar et al., International Journal of Trichology

Modern melanosomes generally carry a mixture of two melanin pigments: dark brown-black eumelanin and red-yellow pheomelanin.

—Meghan Rosen, Science News

The marked spectrum of color and diversity of patterns that we see in mammals arises, unexpectedly, from variation in the quantity, quality, and regional distribution of just two types of pigment—black eumelanin and yellow pheomelanin.

—Sophie I. Candille et al., Science

compare eumelanin, neuromelanin