Evaluating Hair Growth Promoting Effects of Candidate Substances: A Review of Research Methods

The document from 2019 reviews methods for evaluating the hair growth-promoting effects of substances on hair follicle cells, focusing on dermal papilla and outer root sheath cells, which are key in hair growth and the hair cycle. It details how these substances may influence hair growth by affecting signaling pathways and gene expression, and describes the use of cell viability assays, molecule analysis, and marker expression levels to assess these effects. Additionally, it discusses the use of organ culture and animal models to evaluate hair growth outcomes, such as follicle growth rates and anagen induction. The review emphasizes the importance of targeting vellus hair follicles in vitro and the role of epithelial-mesenchymal interactions. It concludes that while laboratory results are promising, clinical human trials are necessary to confirm hair growth promotion in AGA, and highlights the need for more reliable and simple assay methods, mentioning the development of new tools like skin organoids and in silico methods. The research was supported by the National Research Foundation of Korea.