Age-Related Carbonylation of Hair Causes Irregular Shapes

Abstract

This study focused on black and white hairs in individuals over the age of 40 and analyzed qualitative changes of age-related hair. Water-related irregular shapes increased with aging for both high-and low-humidity conditions. Careful observance of the difference between black and white hair revealed that the water-related irregular shape of white hair increased. The result of real-time examinations of water behavior by means of Fourier-transform infrared (FT-IR) microscopy revealed an increase of water penetration and decrease of water holding capacity in white hair. The amount of carbonylated proteins, which have been known an indicator of aging, was significantly greater in white hair than black hair over the age of 50. These results suggested that the carbonylation of interior proteins changed water behavior and was the cause of hair shape. Furthermore, it was considered until now that carbonylated proteins could not return to their previous form, but reductive amination treatments using 5-ethyl-2-methylpyridine borane (PEMB) were revealed to reduce the amount of carbonylated proteins, improving water behavior and hair shape. From the above, further quality-of-life (QOL) improvements can be brought about by not only applying color correction to white hair with conventional coloring, but also combining this with hair shape correction based on reductive amination.