The Science of Melanin, College

The Science of Melanin Magic

Melanin is a family of pigments that gives color to skin, hair and eyes. Dr. Raven Baxter explains three kinds of melanin and what each kind does. She also shows how squids, fungi and other living things use melanin.

Three hands with different skin tones pressed against a white wall — Melancholy, a word for deep sadness, comes from Greek *melancholía*, “condition of having black bile.”

Your word of the day is

MEL-uh-nin

melan-blackfrom Greek mélās

-inan ending for names of chemicalsfrom New Latin -ina

A family of natural pigments that give color to skin, hair, eyes, feathers and more.

Red hair holds a lot of pheomelanin. Chemists track pheomelanin with TTCA, a marker molecule that comes from pheomelanin when hair is broken down.

Before you read the paper, take a guess. Black hair holds what percent of red hair’s TTCA? Give your reason in one sentence.

Hint

Think about which kind of melanin the video says colors black hair.

A woman scientist using a chemistry instrument in a lab

Read the paper

Ito and others, “Improved HPLC Conditions to Determine Eumelanin and Pheomelanin Contents in Biological Samples Using an Ion Pair Reagent,” International Journal of Molecular Sciences, 2020. The paper is free to read.

Chemists measure melanin by breaking the pigment into small marker molecules and measuring the markers. Alkaline hydrogen peroxide breaks eumelanin into PTCA, PDCA and PTeCA, and breaks pheomelanin into TTCA and TDCA. The markers show how much of each melanin a sample holds and what its building blocks look like. Table 2 of the paper reports all five markers in one sample of black human hair and one sample of red human hair, from five repeat analyses. Values are means ± standard deviation, in nanograms of marker per milligram of hair. The coefficient of variation (CV) sits in parentheses. PTCA, PDCA and PTeCA come from eumelanin. TTCA and TDCA come from pheomelanin.

Hair	PTCA	PDCA	PTeCA	TTCA	TDCA	TTCA ÷ PTCA
Black	205 ± 4.4 (2.1%)	19.2 ± 0.60 (3.2%)	82.0 ± 3.6 (4.4%)	43.4 ± 0.94 (2.2%)	19.4 ± 1.9 (9.7%)
Red	23.4 ± 1.2 (5.2%)	10.7 ± 0.52 (4.8%)	12.9 ± 1.6 (12.4%)	169 ± 6.7 (4.0%)	26.7 ± 0.86 (3.2%)

A smiling woman with black curly hair in an afro against a blue background

In Table 2 of Ito’s 2020 paper, black hair held 43.4 ng of TTCA and 205 ng of PTCA per mg.

Black hair’s TTCA ÷ PTCA ratio in Table 2 is ____.

See the table

Hair	PTCA	PDCA	PTeCA	TTCA	TDCA	TTCA ÷ PTCA
Black	205 ± 4.4 (2.1%)	19.2 ± 0.60 (3.2%)	82.0 ± 3.6 (4.4%)	43.4 ± 0.94 (2.2%)	19.4 ± 1.9 (9.7%)
Red	23.4 ± 1.2 (5.2%)	10.7 ± 0.52 (4.8%)	12.9 ± 1.6 (12.4%)	169 ± 6.7 (4.0%)	26.7 ± 0.86 (3.2%)

A smiling man with red hair against a blue background

In Table 2 of Ito’s 2020 paper, red hair held 169 ng of TTCA and 23.4 ng of PTCA per mg.

Red hair’s TTCA ÷ PTCA ratio in Table 2 is ____.

See the table

Hair	PTCA	PDCA	PTeCA	TTCA	TDCA	TTCA ÷ PTCA
Black	205 ± 4.4 (2.1%)	19.2 ± 0.60 (3.2%)	82.0 ± 3.6 (4.4%)	43.4 ± 0.94 (2.2%)	19.4 ± 1.9 (9.7%)
Red	23.4 ± 1.2 (5.2%)	10.7 ± 0.52 (4.8%)	12.9 ± 1.6 (12.4%)	169 ± 6.7 (4.0%)	26.7 ± 0.86 (3.2%)

A row of labeled test tubes in a rack in a lab

In Table 2 of Ito’s 2020 paper, red hair’s TTCA-to-PTCA ratio is about ____ times black hair’s ratio.

See the table

Hair	PTCA	PDCA	PTeCA	TTCA	TDCA	TTCA ÷ PTCA
Black	205 ± 4.4 (2.1%)	19.2 ± 0.60 (3.2%)	82.0 ± 3.6 (4.4%)	43.4 ± 0.94 (2.2%)	19.4 ± 1.9 (9.7%)
Red	23.4 ± 1.2 (5.2%)	10.7 ± 0.52 (4.8%)	12.9 ± 1.6 (12.4%)	169 ± 6.7 (4.0%)	26.7 ± 0.86 (3.2%)

Three young women in blazers, a woman with red hair in front of two women with dark hair

In Table 2 of Ito’s 2020 paper, black hair holds ____ of red hair’s TTCA.

See the table

Hair	PTCA	PDCA	PTeCA	TTCA	TDCA	TTCA ÷ PTCA
Black	205 ± 4.4 (2.1%)	19.2 ± 0.60 (3.2%)	82.0 ± 3.6 (4.4%)	43.4 ± 0.94 (2.2%)	19.4 ± 1.9 (9.7%)
Red	23.4 ± 1.2 (5.2%)	10.7 ± 0.52 (4.8%)	12.9 ± 1.6 (12.4%)	169 ± 6.7 (4.0%)	26.7 ± 0.86 (3.2%)

TTCA holds a sulfur atom. Of the pathway’s starting molecules, only cysteine carries sulfur.

What do the 43.4 ng of TTCA per mg of black hair tell you about cysteine in the melanocytes that colored black hair?

See the table

Hair	PTCA	PDCA	PTeCA	TTCA	TDCA	TTCA ÷ PTCA
Black	205 ± 4.4 (2.1%)	19.2 ± 0.60 (3.2%)	82.0 ± 3.6 (4.4%)	43.4 ± 0.94 (2.2%)	19.4 ± 1.9 (9.7%)
Red	23.4 ± 1.2 (5.2%)	10.7 ± 0.52 (4.8%)	12.9 ± 1.6 (12.4%)	169 ± 6.7 (4.0%)	26.7 ± 0.86 (3.2%)

Rows of sample vials loaded into a chromatograph, a lab machine that separates and measures molecules

In Table 2, PTeCA in red hair had a CV of 12.4% and TDCA in black hair had a CV of 9.7%. Most CVs fell under 5%.

Why would PTeCA in red hair and TDCA in black hair vary more than the other markers in Table 2 of Ito’s paper?

See the table

Hair	PTCA	PDCA	PTeCA	TTCA	TDCA	TTCA ÷ PTCA
Black	205 ± 4.4 (2.1%)	19.2 ± 0.60 (3.2%)	82.0 ± 3.6 (4.4%)	43.4 ± 0.94 (2.2%)	19.4 ± 1.9 (9.7%)
Red	23.4 ± 1.2 (5.2%)	10.7 ± 0.52 (4.8%)	12.9 ± 1.6 (12.4%)	169 ± 6.7 (4.0%)	26.7 ± 0.86 (3.2%)

Why would the chemists in Ito’s 2020 paper run the same hair sample five times?

See the table

Hair	PTCA	PDCA	PTeCA	TTCA	TDCA	TTCA ÷ PTCA
Black	205 ± 4.4 (2.1%)	19.2 ± 0.60 (3.2%)	82.0 ± 3.6 (4.4%)	43.4 ± 0.94 (2.2%)	19.4 ± 1.9 (9.7%)
Red	23.4 ± 1.2 (5.2%)	10.7 ± 0.52 (4.8%)	12.9 ± 1.6 (12.4%)	169 ± 6.7 (4.0%)	26.7 ± 0.86 (3.2%)

A smiling woman with freckles wearing a straw sun hat outdoors

Pheomelanin blocks less UV than eumelanin and can produce reactive oxygen species under UV.

Based on Table 2 of Ito’s paper, which melanocytes would likely give skin less protection from UV?

See the table

Hair	PTCA	PDCA	PTeCA	TTCA	TDCA	TTCA ÷ PTCA
Black	205 ± 4.4 (2.1%)	19.2 ± 0.60 (3.2%)	82.0 ± 3.6 (4.4%)	43.4 ± 0.94 (2.2%)	19.4 ± 1.9 (9.7%)
Red	23.4 ± 1.2 (5.2%)	10.7 ± 0.52 (4.8%)	12.9 ± 1.6 (12.4%)	169 ± 6.7 (4.0%)	26.7 ± 0.86 (3.2%)

A woman scientist in a lab coat looking into a microscope

Which study would best test whether red-hair-type melanocytes give skin less UV protection?

See the table

Hair	PTCA	PDCA	PTeCA	TTCA	TDCA	TTCA ÷ PTCA
Black	205 ± 4.4 (2.1%)	19.2 ± 0.60 (3.2%)	82.0 ± 3.6 (4.4%)	43.4 ± 0.94 (2.2%)	19.4 ± 1.9 (9.7%)
Red	23.4 ± 1.2 (5.2%)	10.7 ± 0.52 (4.8%)	12.9 ± 1.6 (12.4%)	169 ± 6.7 (4.0%)	26.7 ± 0.86 (3.2%)

Four women seen from behind with different hair colors and textures

Table 2 of Ito’s 2020 paper compares five melanin markers in one black hair sample and one red hair sample.

Which summary fits Table 2 of Ito’s 2020 paper?

A crowd of many different people crossing a busy city street

Which question can’t Table 2 of Ito’s 2020 paper answer?

Lesson complete

Today’s word

melanin

MEL-uh-nin

A family of pigments in living things. Cells make eumelanin and pheomelanin from the amino acid tyrosine.

Back to the lesson Start over

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Sources

Shosuke Ito, Sandra Del Bino, Tomohisa Hirobe and Kazumasa Wakamatsu, at Fujita Health University, L’Oréal Research and Innovation and Shinjuku Skin Clinic, International Journal of Molecular Sciences, 2020
Shosuke Ito and Kazumasa Wakamatsu, Fujita Health University, Journal of the European Academy of Dermatology and Venereology, 2011
Michaela Brenner and Vincent Hearing, National Cancer Institute, Photochemistry and Photobiology, 2008
Meredith and Riesz, University of Queensland, Photochemistry and Photobiology, 2004
Erin Wolf Horrell, Mary Boulanger and John D’Orazio, University of Kentucky, Frontiers in Genetics, 2016
Karen Grønskov, Jakob Ek and Karen Brondum-Nielsen, Kennedy Center, Denmark, Orphanet Journal of Rare Diseases, 2007
Sandra Del Bino, Shosuke Ito, Juliette Sok and Kazumasa Wakamatsu, at L’Oréal Research and Innovation and Fujita Health University, Pigment Cell and Melanoma Research, 2022
Commo, Gaillard and Bernard, L’Oréal Recherche, British Journal of Dermatology, 2004
Luigi Zecca and colleagues, PNAS, 2004
Svenja Esser, Maximilian Hausherr and colleagues, Ruhr University Bochum, Biomedicines, 2025
Charles Derby, Georgia State University, Marine Drugs, 2014
Radames Cordero and Arturo Casadevall, Johns Hopkins Bloomberg School of Public Health, Fungal Biology Reviews, 2017
Agnieszka Zdybicka-Barabas, Sylwia Stączek, Magdalena Kunat-Budzyńska and colleagues, Maria Curie-Skłodowska University, International Journal of Molecular Sciences, 2025
Vision and Change core concepts and competencies, as summarized in Brownell and others, CBE Life Sciences Education, 2014
Word origins and formulas from Dictionary.com: melanin, melano-, -in, eumelanin, pheomelanin, neuromelanin, melanocyte, -cyte, eu-, neuro-, melancholy, melanoma, keratin, euphony, tyrosine, cysteine, pyrrole, thiazole
The Metropolitan Museum of Art, “A Happy Occasion for Melencolia I”
Spanish and French spellings from Wiktionary
Transcript from the English captions uploaded with the YouTube video

The Science of Melanin, College

The Science of Melanin Magic

Your word of the day is

Before you read the paper, take a guess. Black hair holds what percent of red hair’s TTCA? Give your reason in one sentence.

Read the paper

Black hair’s TTCA ÷ PTCA ratio in Table 2 is ____.

Red hair’s TTCA ÷ PTCA ratio in Table 2 is ____.

In Table 2 of Ito’s 2020 paper, red hair’s TTCA-to-PTCA ratio is about ____ times black hair’s ratio.

In Table 2 of Ito’s 2020 paper, black hair holds ____ of red hair’s TTCA.

What do the 43.4 ng of TTCA per mg of black hair tell you about cysteine in the melanocytes that colored black hair?

Why would PTeCA in red hair and TDCA in black hair vary more than the other markers in Table 2 of Ito’s paper?

Why would the chemists in Ito’s 2020 paper run the same hair sample five times?

Based on Table 2 of Ito’s paper, which melanocytes would likely give skin less protection from UV?

Which study would best test whether red-hair-type melanocytes give skin less UV protection?

Which summary fits Table 2 of Ito’s 2020 paper?

Which question can’t Table 2 of Ito’s 2020 paper answer?

Lesson complete

Today’s word

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