Bio-based succinic acid (bSU) has emerged as a promising mild exfoliating agent, yet its effects on desquamation pathways, barrier-related protein regulation, and irritation potential remain insufficiently characterized in human-relevant skin models. Therefore, this study systematically evaluated bSU against salicylic acid (SA) using reconstructed human epidermis and human skin explants to assess irritation profile and desquamation-related biological responses. Our findings reveal that bSU facilitates controlled corneocyte shedding by modulating the targets LEKTI, KLK, and CDSN. Moreover, bSU demonstrated a favorable ability to maintain physiological skin surface acidity, all while minimizing inflammatory activation. These results position bSU as a balanced exfoliating bioactive that effectively promotes stratum corneum renewal while preserving cutaneous barrier homeostasis, providing mechanistic insights to support its development in advanced mild exfoliation formulations.

Hair care pretreatments may limit the structural changes caused by chemical, thermal, and ultraviolet (UV) damage. We examined whether biomimetic amino acid (AA) and wool keratin (WK) pretreatments reduced these forms of hair damage. Virgin black human hair fibers were treated with 1% (w/w) AA or WK, washed with sodium laureth sulfate, and then subjected to oxidative bleaching, flat-iron treatment, or UV irradiation. Cuticular morphology was examined by scanning electron microscopy (SEM) and graded using a damage score. Cortical ultrastructure was assessed by transmission electron microscopy (TEM), and the cortical void-like area fraction was measured by quantitative image analysis. Across the three exposure protocols, fibers pretreated with AA or WK showed more continuous cuticular coverage and lower SEM damage scores than non-pretreated fibers exposed to the same conditions. Their cortical matrices were also more continuous, and their cortical void-like area fractions were lower (adjusted p < 0.05). Together, these findings indicate a reduced severity of cuticular and cortical changes relative to the corresponding damage-only group.

We performed a mixed-cohort study to establish the scalp lipid–microbe functional linkages in dandruff using untargeted quantitative lipidomic and shot-gun metagenomic technology. Our findings suggest that suppressing scalp microbes facilitates lipid removal and alleviates dandruff more effectively.