Improved Humidity-Resistant Hair Straightening Using Muconic Acid-Derived Amino Acid Compounds
Year: 2026
Type: article
Abstract: This study investigated the effects of incorporating a novel amino acid compound (CM) into a reductive hair-straightening formulation on hair shape stability, mechanical properties, and surface characteristics. Hair trees from Brazilian donors were treated with a cysteamine-based straightening system, with or without CM, and evaluated under high-temperature, high-humidity conditions (40 °C, 75% relative humidity). CM-treated hair remained straight after 24 h of humidity exposure, whereas the control group exhibited partial or complete loss of the straightening effect. The mean hair spread width significantly decreased in the CM-treated group, indicating improved macroscopic shape stability. Mechanical analysis revealed a significant increase in bending rigidity (p < 0.05), whereas torsional rigidity and torsional hysteresis were significantly decreased (p < 0.01), suggesting direction-dependent changes in fiber mechanics. Furthermore, the coefficient of friction was significantly reduced following CM treatment, and the combing resistance tended to decrease. Scanning electron microscopy images revealed suppression of cuticle deterioration induced by repeated thermal and mechanical stress. Collectively, reduced torsion, improved shape retention, increased bending stiffness, and decreased fiber–fiber friction contributed to the improved combability and enhanced durability of straightening performance. Overall, CM enhanced humidity-resistant straightening while improving the surface and mechanical properties of the hair fibers. These findings suggest that CM is a promising additive for the development of humidity-resistant hair-straightening formulations.
Source: Cosmetics
Institution: Kobe University
Language: English
Subfield: Building and Construction
Field: Engineering
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $2,172
OpenAlex ID: W7203890417