Ecklonia cava Extract as an Anti-Aging Cosmetic Ingredient Enhancing Skin Hydration, Elasticity, and Density

The demand for naturally derived ingredients in cosmetics is constantly growing, with marine algae emerging as promising candidates due to their rich antioxidant and protective metabolites. Skin aging, driven by oxidative stress, impaired hydration, and weakening of the dermal–epidermal junction (DEJ), manifests as dryness, loss of elasticity, and reduced density. Conventional synthetic antioxidants raise safety concerns, highlighting the need for effective natural alternatives. Ecklonia cava, an edible brown seaweed abundant in phlorotannins, has been reported to possess strong antioxidant and anti-inflammatory properties, yet its effects on key molecular markers of hydration and DEJ integrity remain underexplored. In this study, we standardized an E. cava extract (ECE) and evaluated its antioxidant activity, gene regulatory effects, and clinical efficacy. ECE was standardized by measuring total polyphenols and flavonoids, evaluated by DPPH scavenging assay, and shown to upregulate DEJ-related genes, reinforcing dermal–epidermal cohesion. A randomized clinical trial further confirmed that topical application of ECE improved hydration, elasticity, and density compared with placebo, with benefits evident within weeks. Collectively, these findings establish ECE as a multifunctional cosmetic ingredient capable of protecting the skin while enhancing structural and functional aspects of skin health, supporting its potential application in anti-aging skincare.