photobiomodulation

Photobiomodulation refers to the use of non-ionizing light in the red to near-infrared spectrum to elicit biological responses in cells and tissues. It is commonly delivered with lasers or light-emitting diodes (LEDs) at low irradiance in a non-thermal range. The approach is used in research and clinical settings to influence tissue repair, inflammation, pain, and other physiological processes.

The proposed mechanism centers on light absorption by cellular chromophores, especially mitochondrial cytochrome c oxidase. Photoactivation can enhance mitochondrial respiration and adenosine triphosphate (ATP) production, modulate reactive oxygen species signaling, and promote the release of nitric oxide. These primary events can trigger signaling pathways and gene expression changes that influence inflammation, cell proliferation, and tissue regeneration.

Key parameters include wavelength (roughly 600–1100 nm), irradiance, energy density (fluence), exposure duration, and treatment frequency. PBM can be delivered through various devices, including low-level lasers and LED panels, and is typically non-thermal, reducing the risk of tissue heating.

Applications span wound healing, musculoskeletal pain relief, dental therapies such as management of oral mucositis, and emerging research in neurology and dermatology. Evidence is variable across indications; some systematic reviews report modest benefits in certain conditions, while others show inconclusive results. Methodological differences, device heterogeneity, and placebo effects contribute to mixed findings.

Safety is generally favorable when used appropriately, with rare adverse events. Common precautions include eye protection during ocular exposure and avoiding use over active malignancies or photosensitizing drug use. Ongoing research and standardization efforts aim to clarify optimal wavelengths, doses, and indications for photobiomodulation.