Hydrolyzed Keratin Peptide Enhances Hair Condition and Promotes Hair Regeneration

Growing interest in hair health has increased the demand for safe and effective hair growth agents. Keratin, a structural protein abundant in hair, skin, and nails, is essential for maintaining hair integrity and resilience. This study evaluated the effects of orally administered hydrolyzed keratin peptide on hair growth in male and female C57BL/6 mice and its cellular impact on human follicle dermal papilla cells (HFDPCs) and HaCaT keratinocytes. Oral administration of hydrolyzed keratin peptide promoted the telogen-to-anagen transition and increased expression of proliferation markers ( β-catenin, cyclin D1 , and proliferating cell nuclear antigen [ PCNA ]) in both sexes, while upregulating growth factors and antioxidant enzymes in male mice. In vitro , hydrolyzed keratin peptide enhanced HFDPC proliferation by activating β-catenin and improving cellular antioxidant capacity in both HaCaT keratinocytes and HFDPCs. These findings suggest that hydrolyzed keratin peptides are a promising functional food ingredient for promoting hair health through both proliferative and antioxidant mechanisms.