Mechanisms of action and clinical research progress of photobiomodulation.

Photobiomodulation (PBM) involves the application of low-intensity visible or near-infrared light (600-1100 nm) to tissues. PBM demonstrates considerable potential in chronic wound healing, neurodegenerative disease intervention, and adjunctive cancer therapy. The core mechanism of PBM relies on photon absorption at specific wavelengths by mitochondrial cytochrome c oxidase. By activating the mitochondrial electron transport chain, enhancing ATP synthesis, and regulating reactive oxygen species signaling, PBM mediates multiple downstream signaling pathways, including PI3K/Akt, MAPK, and NF-κB, thereby exhibiting significant wavelength- and dose-dependent bidirectional regulatory characteristics. Currently, domestic and international research primarily focuses on single signaling pathways or therapeutic effects for specific diseases, while lacking a systematic review of their multidimensional regulatory mechanisms and multisystem biological effects. This hinders the standardization of treatment parameters and optimization of clinical protocols. Accordingly, this review systematically summarizes the molecular mechanisms and research progress of PBM across five major areas: tissue repair and regeneration, anti-inflammatory and immunomodulatory effects, regulation of glucose and lipid metabolism, tumor intervention, and neuroprotection and analgesia. We identify current research bottlenecks and recognize the uncertainty in therapeutic efficacy caused by parameter variations, along with outlining pathways for its precise and personalized clinical translation. PBM offers unique advantages, including safety, minimal tissue damage, and low cost. These features make it a promising, novel adjunctive therapeutic modality and provide a systematic theoretical basis for developing non-invasive adjunctive phototherapy regimens for various refractory diseases.