Enhanced Anti-Hair Loss Activity of Kelp (Laminaria japonica) Induced by Fermentation Using Saccharomyces cerevisiae

Oxidative stress contributes to hair follicle degeneration by inducing inflammation and apoptosis in dermal papilla cells. This study investigated whether Saccharomyces cerevisiae fermentation enhances the anti-hair loss potential of Laminaria japonica (kelp) by-products by improving their antioxidant, anti-inflammatory, and cytoprotective activities. Fermentation significantly increased the superoxide dismutase (SOD) activity of kelp. In H2O2-stimulated human hair follicle dermal papilla cells, fermented kelp culture (KF) dose-dependently protected against oxidative-stress-induced cytotoxicity, reduced IL-6 and IL-8 secretion, inhibited NFκB phosphorylation, restored insulin-like growth factor-1 (IGF-1) expression, enhanced AKT phosphorylation, reduced Bax expression, and restored total caspase-3 expression. These findings indicate that KF attenuates oxidative-stress-induced inflammation and apoptosis while preserving dermal papilla cell function. A four-week application study further showed that a shampoo containing KF reduced hair loss and improved hair gloss, scalp sebum, and scalp scaling. Together, these findings suggest that S. cerevisiae fermentation enhances the biological activity of kelp by-products and supports the potential of KF as a functional cosmetic ingredient for anti-hair loss applications.