Efficacy of Nano-Sized Ultrafine Water Clusters in Reducing Erythema Following Fractionated Picosecond Alexandrite Laser Treatment: A Split-Face, Randomized, Evaluator-Blinded Pilot Study

Post-procedural erythema following energy-based dermatological treatments is a common concern affecting patient satisfaction and downtime. Nano-sized ultrafine water clusters (UFW), generated by conductive polymer poly(3,4-ethylenedioxythiophene)–poly(styrene sulfonate) (PEDOT/PSS) technology, represent a novel form of water with unique physicochemical properties (average particle diameter ≈ 1.4 nm). This split-face, randomized, evaluator-blinded pilot study evaluated the efficacy of UFW in reducing erythema following fractionated picosecond alexandrite laser (Fr-PSAL) treatment with a diffractive lens array. Twenty-five female subjects were assigned to a pre-treatment (n = 13) or post-treatment (n = 12) group. UFW was applied for 30 minutes to one randomly selected facial side; the contralateral side served as control. A board-certified dermatologist, blinded to allocation, correctly identified the UFW-treated side in 11/12 post-treatment subjects (91.7%, p = 0.003) and 11/13 pre-treatment subjects (84.6%, p = 0.011). Exploratory semi-quantitative hemoglobin-enhanced image analysis corroborated these findings: erythema density was significantly reduced in the post-treatment group (Cohen’s d = − 0.93, p = 0.004) and erythema area in the pre-treatment group (d = − 0.57, p = 0.031). No adverse events were observed. These results provide the first clinical evidence that UFW effectively reduces post-laser erythema through both therapeutic and prophylactic mechanisms.