Open AccessEffects of lactic acid on the flexibility of the stratum corneum
Author(s) -
Mizukoshi Koji
Publication year - 2020
Publication title -
skin research and technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.521
H-Index - 69
eISSN - 1600-0846
pISSN - 0909-752X
DOI - 10.1111/srt.12841
Subject(s) - stratum corneum , lactic acid , flexibility (engineering) , chemistry , food science , zoology , biology , bacteria , mathematics , statistics , genetics
Background Lactic acid increases the flexibility of the stratum corneum by linking directly to keratin without water. However, another study reported the involvement of water. This study aimed to clarify how lactic acid contributes to the flexibility of the stratum corneum (SC) of the face. Materials and Methods A tactile sensor was used to measure the change in shared frequency (Δf) in the cheeks of 88 women of various ages. Amounts of water and lactic acid in the SC were measured during all four seasons, and correlations with Δf evaluated. Results Lactic acid and water levels in the SC were not correlated in any season. In the younger subjects only, the lactic acid content correlated with Δf in spring (when at its highest level in the SC), whereas the water content correlated with Δf in summer and autumn (when the water content was high). Conclusions The overall lack of correlations between lactic acid and water content across all ages and seasons suggested that each contributes independently to the flexibility of the SC and that lactic acid softens the SC without water.