Mitochondria and light: An overview of the pathways triggered in skin and retina with incident infrared radiation Author: Daniel Arranz-Paraíso1, Yolanda Sola2, David Baeza-Moyano3, Marta Benítez-Martínez4, Sofía Melero-Tur5, Roberto Alonso González-Lezcano6 Affiliation: <sup>1</sup> Área de conocimiento de Tecnología Farmacéutica, Departamento de Ciencias Farmacéuticas y de la Salud, Facultad de Farmacia, Universidad San Pablo-CEU, CEU Universities, Urbanización Montepríncipe, 28668 Alcorcón, Madrid, Spain. Electronic address: daniel.arranzparaiso@ceu.es. <sup>2</sup> Group of Meteorology, Department of Applied Physics, Universitat de Barcelona, Martí i Franquès 1, 08028 Barcelona, Spain. Electronic address: ysola@meteo.ub.edu. <sup>3</sup> Departamento de Química y Bioquímica, Facultad de Farmacia, Universidad San Pablo-CEU, CEU Universities, Urbanización Montepríncipe, 28668 Alcorcón, Madrid, Spain. Electronic address: baezams@ceu.es. <sup>4</sup> Departamento de Química y Bioquímica, Facultad de Farmacia, Universidad San Pablo-CEU, CEU Universities, Urbanización Montepríncipe, 28668 Alcorcón, Madrid, Spain. Electronic address: m.benitez6@usp.ceu.es. <sup>5</sup> Departamento de arquitectura y diseño, Escuela Politécnica Superior, Universidad San Pablo-CEU, CEU Universities, Urbanización Montepríncipe, 28668 Alcorcón, Madrid, Spain. Electronic address: sofia.melerotur@ceu.es. <sup>6</sup> Departamento de arquitectura y diseño, Escuela Politécnica Superior, Universidad San Pablo-CEU, CEU Universities, Urbanización Montepríncipe, 28668 Alcorcón, Madrid, Spain. Electronic address: rgonzalezcano@ceu.es. Conference/Journal: J Photochem Photobiol B Date published: 2022 Nov 30 Other: Volume ID: 238 , Pages: 112614 , Special Notes: doi: 10.1016/j.jphotobiol.2022.112614. , Word Count: 192 Slightly more than half of the solar radiation that passes through the atmosphere and reaches the Earth's surface is infrared. Over the past few years, many papers have been published on the possible positive effects of receiving this part of the electromagnetic spectrum. In this article we analyse the role of mitochondria in the supposed effects of infrared light based on the published literature. It is claimed that ATP synthesis is stimulated, which has a positive effect on the skin by increasing fibroblast proliferation, anchorage and production of collagen fibres, procollagen, and various cytokines responsible for the wound healing process, such as keratinocyte growth factor. Currently there are infrared light emitting equipment whose manufacturers and the centres where this service or treatment is offered claim that they are used for skin rejuvenation among other positive effects. Based on the literature review, it is necessary to deepen the scientific study of the mechanism of absorption of infrared radiation through the skin to better understand its possible positive effects, the risks of overexposure and to improve consumer health protection. Keywords: ATP; BK(Ca); Cellular health; Metabolism; Mitochondria; R/NIR; ROS. PMID: 36469983 DOI: 10.1016/j.jphotobiol.2022.112614