Red and near-infrared light stimulate mitochondria inside cells, particularly the enzyme cytochrome-c-oxidase. This increases cellular energy production (ATP), reduces oxidative stress, and activates repair pathways. In skin specifically, studies show photobiomodulation can: - stimulate fibroblast activity - increase collagen synthesis - improve dermal density and elasticity - reduce wrinkle depth and skin roughness after repeated treatments. Some dermatology research even suggests certain energy-based light devices may influence cellular senescence pathways, meaning they could affect deeper biological mechanisms of aging, not just appearance.