Clinical Efficacy of Wine Lees Extract on Skin Brightness: In vitro and aRandomized Controlled Trial

Introduction: Wine lees are a winemaking byproduct rich in antioxidants; however, their potential as a nutraceutical ingredient remains underutilized. This study aimed to investigate the skin-brightening potential of wine lees extract (WLE) through in vitro assays and a randomized, double-blind, placebo-controlled clinical trial, and to identify its active compounds Methods: The effects of WLE and its active compounds on tyrosinase gene expression, tyrosinase activity, and melanin production were evaluated using B16 murine melanoma cells. Additionally, the clinical efficacy of oral administration of WLE (100 mg/day) was assessed in a 15-week randomized controlled trial involving 23 healthy participants aged 20–50 years. Skin brightness was measured using a skin color sensor and evaluated based on Munsell scores, while subjective skin parameters were assessed using a Visual Analog Scale (VAS). Results: WLE significantly suppressed tyrosinase gene expression, tyrosinase activity, and melanin production in B16 cells. Bioassay-guided fractionation revealed three primary active compounds: syringic acid (SA), protocatechuic aldehyde (PCA), and vanillic acid (VA). In the clinical trial, compared with the placebo group, WLE significantly improved forearm skin brightness and subjective assessments of moisture feeling and brightness after 15 weeks of administration Discussion: This study provides the first clinical evidence that WLE exerts skin-brightening effects through the suppression of melanogenesis. The improvement in forearm skin brightness observed after 15 weeks of supplementation is likely attributable to the synergistic action of three phenolic acids (SA, PCA, and VA). In addition, VAS analysis indicated that WLE improves skin moisture. Taken together, these findings suggest that WLE has potential benefits for overall skin condition. Conclusion: Daily oral intake of WLE (100 mg/day) for 15 weeks improves skin brightness, suggesting its potential as a nutraceutical ingredient for promoting skin radiance.