Novel Compounds for Hair Repair: Chemical Characterization and In Vitro Analysis of Thiol Cross-Linking Agents

The study explores novel thiol cross-linking agents, APA, STA, and SAA, for hair repair by restoring disulfide bonds in damaged hair. These compounds were synthesized and confirmed for high purity using spectroscopic techniques. APA demonstrated superior cross-linking potential, achieving 81.5% bis-adduct formation, and outperformed the commercial product Olaplex® in improving hair strength and elasticity. Tensile tests on 50 pre-damaged Caucasian hair fibers per treatment showed significant enhancements in hair quality, particularly with immediate post-bleaching treatment. The findings suggest these agents have promising applications in hair repair formulations, though further in vivo testing is needed.