Highlights
- Photobiomodulation (PBM) is a non-thermal light therapy using red and near-infrared wavelengths.
- PBM acts primarily at the mitochondrial level, especially on cytochrome c oxidase.
- The therapy modulates ATP production, oxidative stress, inflammation, and nitric oxide signaling.
- PBM has demonstrated neuroprotective, analgesic, and tissue-repair effects.
- A wide range of neurological, musculoskeletal, and regenerative applications have been reported.
Definition and Core Mechanism
Photobiomodulation (PBM), also known as low-level laser therapy (LLLT) or cold laser therapy, is a non-thermal light-based intervention that uses wavelengths primarily in the red (600–700 nm) and near-infrared (750–1100 nm) spectrum to modulate biological processes at the cellular level.
The primary mechanism of action involves photon absorption by mitochondrial chromophores, particularly cytochrome c oxidase (CCO) within the electron transport chain. This interaction enhances mitochondrial respiration and cellular energy metabolism.
Mechanisms of Action
PBM has been shown to influence multiple biological pathways:
- Mitochondrial stimulation: Increased ATP synthesis through enhanced CCO activity
- Redox modulation: Regulation of reactive oxygen species (ROS) within physiological ranges
- Nitric oxide signaling: Release of NO, improving vasodilation and microcirculation
- Anti-inflammatory effects: Reduction of pro-inflammatory cytokines and upregulation of anti-inflammatory mediators
- Neuroplasticity: Activation of BDNF pathways supporting neurogenesis and synaptogenesis
Clinical Applications
Based on preclinical and clinical evidence, PBM has been explored in:
- Neurological disorders (Alzheimer’s disease, Parkinson’s disease, stroke, traumatic brain injury)
- Pain management (arthritis, myofascial pain, neuropathies)
- Wound healing and tissue regeneration
- Sports medicine and muscle recovery
Takeaway
Photobiomodulation represents a scientifically grounded, non-invasive therapeutic approach capable of modulating cellular bioenergetics, inflammation, and tissue repair. Its broad range of biological effects explains the growing interest in PBM across medical, rehabilitative, and integrative health disciplines.
References:
Cotler, H. B., Chow, R. T., Hamblin, M. R., & Carroll, J. (2015). The use of low-level laser therapy (LLLT) for musculoskeletal pain. MOJ Orthopedics & Rheumatology, 2(5), 00068. DOI: 10.15406/mojor.2015.02.00068
de Freitas, L. F., & Hamblin, M. R. (2016). Proposed mechanisms of photobiomodulation or low-level light therapy. IEEE Journal of Selected Topics in Quantum Electronics, 22(3), 7000417. DOI: 10.1109/JSTQE.2016.2561201
Hamblin, M. R. (2017). Mechanisms and applications of the anti-inflammatory effects of photobiomodulation. AIMS Biophysics, 4(3), 337–361. DOI: 10.3934/biophy.2017.3.337
Hennessy, M., & Hamblin, M. R. (2017). Photobiomodulation and the brain: A new paradigm. Journal of Optics, 19(1), 013003. DOI: 10.1088/2040-8986/19/1/013003
Leal, E. C. P., Lopes-Martins, R. A. B., Frigo, L., et al. (2018). Effects of photobiomodulation therapy on delayed onset muscle soreness (DOMS): A systematic review and meta-analysis. Lasers in Medical Science, 33(7), 1463–1477. DOI: 10.1007/s10103-018-2535-7