THE INFLUENCE OF THE PH OF CHEMICAL PRODUCTS ON HAIR HEALTH AFTER BLEACHING

Abstract

This study aimed to analyze, through a qualitative literature review, the influence of the pH of chemical products on hair health after the bleaching process, considering damage mechanisms, mitigation strategies, and implications for formulation and professional practice. Nine scientific articles of direct relevance were selected, published in peer-reviewed journals, addressing the structure and composition of the hair fiber as well as the effects of different pH ranges on the cuticle, cortex, and superficial lipid layer. The analysis showed that high alkaline pH, necessary for the action of oxidizing agents, causes significant cuticle lifting, protein degradation, removal of structural lipids, and increased porosity, enhancing both physical and chemical wear of the fiber. It was also found that maintaining alkalinity after the procedure keeps residual oxidation active, prolonging damage even after rinsing. The evidence gathered indicates that immediate pH neutralization is essential to interrupt degradation processes, promote cuticle closure, and create suitable conditions for reconstructive and nutritive treatments. Protocols incorporating continuous maintenance of pH within the physiological range proved more effective in preserving hair integrity, reducing the recurrence of damage, and increasing aesthetic durability. This research contributes by systematizing knowledge that relates pH variations to structural and functional results, providing support for the development of products with buffering systems and for the implementation of more efficient technical routines. It is concluded that strategic pH control should be understood as a fundamental component in post-bleaching care, with immediate and sustained application to ensure better mechanical performance, structural protection, and maintenance of hair aesthetic quality.