A Hair Growth-Enhancing Component of Hydrolysate of Human Placenta: In vitro and In vivo Assessments

Background: Human placenta hydrolysate (HPH) has been used to promote wound healing, for its anti-aging effects, and, more recently, for hair growth. However, the main component(s) of HPH that induce hair growth remain unknown. Aim: To test the hypothesis that IGF-1, a component of HPH, promotes hair growth and to evaluate the possible mechanism. Methods: We examined the effects of IGF-1 and an amino acid mixture on the cell viability of human dermal papilla cells and on GSK-3β and beta-catenin signaling pathways. We also examined the effects of IGF-1 on the development of hair follicles in C57BL6/J mice using hematoxylin and eosin staining. Results: We found that IGF-1 modulated hair growth signal. Specifically, it increased both the number and size of hair follicles in groups treated with IGF-1 and with the amino acid mixture. Conclusions: IGF-1 and amino acids are active components of HPH in stimulating hair growth activity and HPH could be used as a drug candidate for treatment of alopecia.