Photobiomodulation or PBM is the science of using light to modulate biological mechanisms at the cellular level to speed up tissue repair, improve circulation, and improve cellular energy.  More specifically, PBM refers to the administration of light in the visible red and invisible near-infrared (NIR) spectrum (600 to ~1000 nm) using a range of delivery devices (i.e., headsets, handheld devices, full-body pods) and light sources (i.e., lasers and LED).   It can be used as a stand-alone therapy for a number of mental and physical health conditions, but it is best when it is used as an adjunct or add-on therapy with more traditional treatments and therapies.  

The Discovery of PBM

Photobiomodulation (PBM) was “accidentally” discovered in 1967 by Endre Mester, a Hungarian scientist who was trying to replicate a recent experiment by a US-based researcher by the name of McGuff.  

  • McGuff uses a high-powered ruby laser to destroy a cancerous tumor in a laboratory rat.

  • Mester accidentally used a less powerful ruby laser which did not destroy the tumor, but stimulated hair regrowth and wound regeneration at the surgical site,.

  • Mester published a number of manuscripts that discussed these findings which he termed “laser biostimulation."

  • This technology became more commonly known as “low level laser therapy” or LLLT.

  • In the beginning, many studies demonstrated that LLLT could be used to improve wound healing, reduce pain and inflammation following orthopedic injury and/or surgery.

  • With the advent of light-emitting diodes (LED), LLLT became known as “low-level light therapy” (also LLLT).   

  • The term photobiomodulation or PBM was recently adapted due to the inexact nature of the term “low level.”

Since that time, there has been a growing interest in light therapies as a means of improving physical and mental health in individual patients and/or clients. 

  • I'm a paragraph. Click here to add your own text and edit me. It's easy.

The mechanism by which PBM benefits cell health is currently under intense investigation, but most studies demonstrate at least three main mechanisms of biological action.  

  • First, PBM positively improves the efficiency of energy production in the individual cell.  This occurs when nitric oxide (NO) is displaced (called photodissociation) and the mitochondrial membrane potential is changed.  This causes the mitochondria to consume more oxygen and glucose.  This ultimately leads to increased ATP production, which is the basis of cell energy.   When the cells are able to produce energy more efficiently, they often return to normal functions and stabilize cell health.  

  • Second, PBM consistently improves circulation by increasing the amount of freely available nitric oxide (NO).  NO causes the blood vessels to relax thereby increasing the volume of blood in the tissue.  Improved circulation restores normal levels of available oxygen and other nutrients needed by the tissue.  It also improves the removal of metabolic waste and cell debris.     

  • Third, reduction in inflammation (edema) is often one of the most immediate and consistently reported benefits of PBM.  This happens as a series of cell processes are modified (signaling pathways) leading to a reduction in immune cell activation.  Simple aches, pains, joint stiffness, and swelling tend to disappear and are directly related to this reduction in inflammation.  

  • Following treatment, there appears to be a brief increase in reactive oxygen species (ROS) produced by the mitochondria when exposed to PBM.  These ROSs trigger complex signaling pathways leading to several protective biological processes including cytoprotective, antioxidant, and anti-apoptotic effects that are beneficial to the body in promoting better health and cellular longevity.

  • Other signaling pathways activated by PBM may also be contributing to cellular repair (especially in the brain) and ultimately lead to increased production of cellular proteins that promote the survival, development, and function of neurons (neurotrophins) as well as promote the growth of new cells (neurogenesis) and connections (synaptogenesis).  

  • There appear to be additional receptors on the cell that react to light (photoreceptors) that change the membrane of the cells allowing chemicals and proteins to be transported back and forth more efficiently.  

The combination of these different biological actions contributes to improved function, performance, and resilience of cells leading to enhanced physical and mental health.  In addition, the combination of these biological actions may not just lead to tissue repair but may contribute to more complete healing of tissue especially when combined with other more traditional therapies.  However, there remains much to be learned about the possible impact of PBM on any number of clinical conditions and there are a growing number of clinical trials examining the impact of PBM in improving functional outcomes.  

Effects of PBM