Changes in Shape and Internal Structure Caused by Cyclical Extension of “Yugami Hair” and Development of It's a Solution

Abstract

The study aimed to examine the relationship between age-related curved hair, commonly known as“yugami hair”， and the act of repeatedly stretching the hair, which is a common daily hair grooming practice that causes styling difficulties. Firstly, we conducted a survey on the hair care behavior of individuals with yugami hair, which revealed that although they repeatedly combed their hair to prevent undulations and unruly hair, they still found it less manageable. Subsequently, straight and yugami hair samples were obtained based on morphological parameters, followed by cyclical extension conducted under conditions of load stress that are commonly encountered in daily life. Our results indicate a significant increase in the average curvature of yugami hair, which implies that a reduction in the structural stability of intermediate filaments, the protein found within hair, may be a contributing factor. Furthermore, we identified PPG-2 arginine as a component that can suppress the shape and structural changes of yugami hair.