Influence of Scalp Problems on Physical Properties of Hair and Their Prevention by Plant Extracts

This study observed the scalp conditions of 101 Japanese women and found that those with more severe scalp issues had higher sebum levels and weaker hair strength. It suggested that sebum-derived irritants could cause scalp problems, leading to the release of inflammatory factors that inhibit hair formation at the genetic level. Experiments showed that lipid peroxides increased the expression of inflammatory cytokines (IL-1, IL-8), which reduced the expression of KAP5.1, a gene contributing to cuticle strength. The study also identified plant extracts that could suppress the gene expression of these inflammatory cytokines, indicating their potential to prevent hair weakening caused by scalp issues.