R. Schütz, R. Campiche, M. Gempeler, J. Vollhardt
Unlike UV, to date there has been little clinical research into the immediate and chronic effects of blue light on skin. Therefore
we aimed to specifically investigate skin hyperpigmentation in human subjects caused by blue light. Our initial study, the first
of its kind, assessed hyperpigmentation induced by single, high-dose or repetitive, moderate doses of LED blue-light exposure
in vivo. In a placebo-controlled trial the study substantiated the protective effects of an SPF30 sunscreen formulation containing
light-scattering UV filter particles. The filter combination was selected by an in silico tool for predicting sunscreen formulation
performance in the blue light range. Evidence from the literature further indicates an association between the exposure of skin
to blue light and the formation of reactive oxygen species (ROS). Previously, we demonstrated – through in vitro and ex vivo
experiments - that a formulation containing a microalgae extract of Scenedesmus rubescens could enhance skin resilience to
blue light-induced ROS formation. Here we report on the first clinical study with this microalgae product, which also confirms
the protective effect against blue light irradiation in vivo. As a consequence we have developed a multi-mechanistic strategy for
the prevention of hyperpigmentation caused by exposure to blue light.
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