Oral supplementation with piceatannol improves skin hydration and reduces wrinkle severity: a randomized, double-blind, placebo-controlled trial. - Seto Y; Tsukiashi M; Yamaguchi T; Kawakami S; Maruki-Uchida H; Nishimura E; Mori S; Ito M; Jin K; Maeda K; Iemoto N (Frontiers in nutrition, 2026)