Impact of Oxidative Hair Coloring and Bleaching on Hair Fiber Properties

The study investigates the effects of professional and at-home hair coloring treatments on hair fiber properties, specifically focusing on combability, color, and protein loss in dark-brown virgin hair strands. The research involved eight different treatments using bleaching powders, hydrogen peroxide, and permanent dyes. Results showed that bleaching caused the most significant color change and increased combing force by 46.6%, while coloration treatments improved combability by up to 46.5%. All treatments resulted in substantial protein loss, ranging from 5.1 to 16.6 mg albumin equivalents per gram of hair, compared to 0.7 mg in control strands. Bleaching was found to compromise hair structural integrity, whereas dye formulations with emulsifiers partially reduced damage and enhanced combability, though both processes led to significant keratin degradation.