How Photobiomodulation works

Photobiomodulation (PBM Therapy) previously known as Low Level Laser Therapy (LLLT) has a photochemical effect (like photosynthesis in plants). One of the main mechanisms of this action occurs in the mitochondria (the cellular power plant inside every cell). The effect dependsĀ on the application of the correct wavelength and density of light, delivered to the target tissues for an appropriate period of time (typically between 30 - 60 seconds). Pulses can improve tissue repair and anti-inflammatory effect, analgesia is best achieved with a continuous beam.


The primary effect occurs when light is absorbed in cytochrome c oxidase a protein within the mitochondria.

When cells get stressed (perhaps due to disease, injury or ageing) the mitochondria produces nitric oxide (NO). This competitively displaces oxygen from cytochrome c oxidase consequently reducing ATP (an essential intracellular cellular energy and extracellular signalling molecule) and causing an over production reactive oxygen species (ROS) and leading to oxidative stress. Oxidative stress is well known to lead to inflammation an cell death via the gene transcription factor NF-Kb.

PBM of the correct wavelength and density, dissociates NO allowing oxygen back in, so ATP is restored and oxidative stress reduced. Once normal mitochondrial function is restored by PBM then cell metabolism is improves, and the patient gets better more quickly.

Wellman Center for Photomedicine.