Upcycled Postbiotic Cell-Free Supernatants from Limosilactobacillus fermentum MG901 and MG4237 Alleviated Oxidative Stress-Induced Dysfunction in Human Follicle Dermal Papilla Cells

Oxidative stress–induced dysfunction of hair follicle dermal papilla cells (HFDPCs) is a key factor in the progression of hair loss. In this study, upcycled postbiotic cell-free supernatants (CFSs), derived from Limosilactobacillus fermentum (L. fermentum) MG901 and MG4237, which are typically discarded after fermentation, were evaluated for their protective effects in H2O2-damaged human dermal papilla cells. The CFS exhibited no cytotoxicity and significantly enhanced wound-healing capacity while suppressing intracellular reactive oxygen species accumulation under oxidative stress conditions. In addition, treatment with CFS restored mitochondrial function, indicating recovery from H2O2-induced cellular damage. Dermal papilla cell-specific functional markers, including alkaline phosphatase activity, were also significantly increased following treatment. Mechanistic analyses further revealed that these protective effects were associated with modulation of Wnt/β-catenin signaling as well as regulation of mitochondrial function. Collectively, these findings suggest that upcycled postbiotic CFS from L. fermentum MG901 and MG4237 mitigates oxidative stress-induced dermal papilla cell dysfunction, supporting its potential application as a sustainable cosmetic ingredient for alleviating hair loss.