Synthesis of a New Amino Acid Derivative with Long-Lasting Hair Shape Control Effects and Elucidation of Its Mechanisms

The study introduces a novel hair treatment using 2-(2-aminoethylthio) succinic acid (ATS), derived from cysteamine and fumaric acid, which effectively straightens extremely curly hair with long-lasting effects. Tested on African human hair, ATS outperformed traditional methods without harsh chemicals like formaldehyde. It improves curl retention, reduces friction, and increases moisture content, enhancing hair styling. Microscopic analysis showed ATS reduces flat spots, making hair appear straighter, while SAXS measurements indicated ATS widens the distance between intermediate filaments, improving orientation and causing matrix swelling. This swelling increases moisture absorption, weakens hydrogen bonds, and alters hair's physical properties, offering a promising alternative for hair straightening with reduced damage and health risks.