Photochemical Alterations in Human Hair: Artificial Irradiation and Investigations of Hair Proteins

The study constructed equipment to irradiate human hair with artificial sunlight, mimicking natural sunlight's spectral distribution and intensity. It examined the photodamage to hair proteins in black and light-brown hair, focusing on different segments of the sunlight spectrum and hair fiber regions (cortex and cuticle). Results showed that melanin in the cortex of black hair provided significant photoprotection, reducing photodamage, while the cuticle, lacking pigment, experienced similar photodegradation in both black and light-brown hair.