Analysis of the Degradation Patterns of Melanin Granules in Bleached Hair

Abstract

The degradation patterns of melanin granules in cross-sectional bleached hair were studied using transmission electron microscopy. In ammonia- or monoethanolamine-bleached hair, melanin granules were decomposed from the inner to the outer layers of the hair. In contrast, in the carbonate- or persulfate-bleached hair, melanin granules were decomposed from the outer to the inner layers of the hair. These results were suggested to be related to the heterogeneous distribution of melanin granules in the cortex, differences of permeability to the hair and oxidative reactivity to melanin granules of bleaching ingredients. Using ammonia and carbonate bleach, melanin granules were homogeneously decomposed in the whole hair effectively.