 Photobiomodulation, PBM, is a therapy that uses red and near-infrared light to stimulate healing, relieve pain, and reduce inflammation. The primary chromophores are cytochrome C oxidase in mitochondria and calcium ion channels. PBM can increase ATP levels, produce reactive oxygen species, and modulate calcium levels. It activates a wide range of transcription factors leading to improved cell survival, increased proliferation and migration, and new protein synthesis. PBM has a biphasic dose response, with low levels of light having stimulating effects while high levels have inhibitory effects. PBM can reduce inflammation in various animal models and tissues, including the brain, abdominal fat, wounds, lungs, and spinal cord. It reduces markers of M1 phenotype in activated macrophages and reactive nitrogen species and prostaglandins in various animal models. This article was authored by Michael R. Hamblin. We are article.tv, links in the description below.