Tryptophan in Human Hair: Correlation with Pigmentation

August 2000 in “ Il Farmaco ”

Antonella Bertazzo, Monica Biasiolo, Carlo Costa, Edda Cardin de Stefani, Graziella Allegri

tryptophan hair pigmentation keratinization

TLDR Men have more tryptophan in their hair than women, and it increases with age and is higher in darker and grey or white hair.

The study analyzed tryptophan levels in 1211 hair samples from healthy individuals to investigate its correlation with hair pigmentation. Results showed that tryptophan levels were higher in males (37.83±3.45 μg/g) than in females (26.62±2.40 μg/g) and varied with age, being highest in early childhood and older age groups. Tryptophan content was also higher in darker hair colors (brown and black) compared to blond hair, and highest in grey and white hair, indicating accumulation with age. The study concluded that tryptophan levels in hair are influenced by sex, age, and hair color.

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Related Research

2 / 2 results

research Tryptophan in Human Hair: Correlation with Pigmentation

16 citations, August 2000 in “Il Farmaco”

Men have more tryptophan in their hair than women, and it increases with age and is higher in darker and grey or white hair.

research Influence of Pigmentation on the Codeine Content of Hair Fibers in Guinea Pigs

53 citations, November 1997 in “Journal of Forensic Sciences”

Darker hair in guinea pigs holds more codeine than lighter hair.