Reinforcing chemically treated human hair with citric acid

The study investigates the effects of citric acid (CA) on chemically treated hair, revealing that CA enhances the structural integrity of hair damaged by treatments such as bleaching and coloring. The research utilized various physical and chemical analysis techniques, showing that CA increases the crosslinking density of keratin-associated proteins, leading to improved mechanical properties like tensile strength and fatigue resistance. Additionally, CA significantly reduces hair calcium levels and crystallized calcium soaps. The study concludes that while CA effectively reinforces damaged hair, its performance varies depending on the type of chemical treatment, indicating a need for further research to develop targeted hair care solutions for specific damage profiles.