What is Photobiomodulation?

Photobiomodulation (PBM), commonly known as light therapy, is a non-invasive treatment modality that utilizes light of specific wavelengths to stimulate biological processes within cells.

One can naturally, and very simply, harness some of the therapeutic properties of light just by spending time outdoors during the day. There are also a multitude of different engineered devices and mechanisms of delivery, most of which narrowly specify the wavelength they generate.

PBM has gained significant attention in recent years due to its potential therapeutic applications in various fields, including health and medicine.

How Does Light Therapy Work?

During Photobiomodulation, the wavelength gives an indication of where it falls on the electromagnetic spectrum. Shorter wavelengths are closer to the ultraviolet range with longer wavelengths extending to the infrared range. Many light therapies, such as lasers, fall outside of the visible light spectrum. The human eye is typically able to detect light frequencies between 380nm-750nm. Some of the most common types of light therapy are near-chromotherapy, infrared, laser, and LED.

The leading areas of investigation regarding PBM are centered around lowering inflammation and increasing cellular energy. These two key processes contribute to a multitude of  biophysical and energetic manifestations, including wound healing, neurological disorders, hair loss, and more.

Photomodulation/Light Therapy Research Outcomes: 

Wound Healing: 

PBM has shown promising results in accelerating wound healing. A review of 68 studies on the use of LED and laser on wound healing corroborated its effectiveness in promoting the closure of chronic wounds, such as diabetic ulcers and pressure sores. PBM stimulates cellular activity and enhances blood circulation, leading to faster tissue repair and reduced inflammation. (a).

Additionally, PBM has been investigated for its analgesic properties. It can help alleviate pain associated with various conditions, such as musculoskeletal disorders, neuropathic pain, and postoperative pain.

PBM works by reducing inflammation, modulating nerve activity, and stimulating the release of endogenous opioids. Interestingly, a systematic review indicates PBM in the 780-830mn range was efficacious in treating and managing tooth and mouth pain during orthodontic treatment. Chronic pain is one of the most common conditions in adult populations with over 50 million Americans reporting chronic pain lasting longer than three months (b).

Neurological Disorders: 

One of the most intriguing and impactful areas of study is within the field of neurological disorders. Researchers have explored the potential of PBM in treating neurological conditions like traumatic brain injury, stroke, and neurodegenerative disorders like Alzheimer's (c, j).

Preclinical studies suggest that PBM can promote neuroprotection, enhance neuronal function and regeneration, and reduce neuroinflammation. One study observed a significant reduction in amyloid plaques in Alzheimer's disease positive mice who were treated with 810nm wavelength light for 20m sessions three times a week for 14 weeks (c).

The non-invasive nature of the therapy and ability to slow or even halt the progression of a deadly debilitating condition that affects millions of individuals has profound potential implications for neurodegenerative disorders.

Stem Cell Transplantation: 

Emerging research in the area of stem cell transplantation indicates the potential for pre-treatment of Human umbilical cord blood (hUCB)‑derived hematopoietic stem cells (HSCs) with PBM prior to transplantation. This step increases engraftment and success of transplantation (i).

One of the most common complications of stem cell transplant is failure of the transplant to ‘root’ in the body, this can lead to catastrophic outcomes. The potentiality of a non-invasive therapy to be able to improve the success of transplantation is significant.

Hair Loss: 

Although not a life threatening condition, hair loss still has a significant impact on quality of life. PBM has been investigated as a potential therapy for hair loss conditions like androgenetic alopecia. Preliminary studies suggest that PBM can stimulate hair follicles, enhance blood flow, and promote hair growth. It may be used as a standalone treatment or in combination with other approaches for better outcomes. (d).

Performance and Recovery:

One of the earliest fields to adopt PBM is sports performance and recovery. Athletes and sports enthusiasts are increasingly using PBM to enhance performance and aid in post-exercise recovery. PBM can improve muscle recovery, reduce muscle fatigue and soreness, and potentially enhance muscle strength and endurance (e).

Bioenergetic Viewpoint:

As Einstein famously stated, “The future of medicine will be the medicine of frequencies”. When we look to correct imbalances in the body’s energetic field it is natural that light, which is simply the expression of energy at particular wavelengths, holds therapeutic value and is an effective tool to consider.

1. Chaves, M. E., Araújo, A. R., Piancastelli, A. C., & Pinotti, M. (2014). Effects of low-power light therapy on wound healing: LASER x LED. Anais brasileiros de dermatologia, 89(4), 616–623. https://doi.org/10.1590/abd1806-4841.20142519
2. Domínguez Camacho, Angela (12/01/2020). "A systematic review of the effective laser wavelength range in delivering photobiomodulation for pain relief in active orthodontic treatment". International orthodontics , 18 (4), p. 684.
3. Gwang Moo Cho, MS et al., Photobiomodulation Using a Low-Level Light-Emitting Diode Improves Cognitive Dysfunction in the 5XFAD Mouse Model of Alzheimer’s Disease, The Journals of Gerontology: Series A, Volume 75, Issue 4, April 2020, Pages 631–639, https://doi-org.proxy.lib.duke.edu/10.1093/gerona/gly240
4. Torres, A. E., & Lim, H. W. (2021). Photobiomodulation for the management of hair loss. Photodermatology, Photoimmunology & Photomedicine, 37(2), 91-98. https://doi.org/10.1111/phpp.12649
5. Pinto, H. D., Vanin, A. A., Miranda, E. F., Tomazoni, S. S., Johnson, D. S., Albuquerque-Pontes, G. M., Aleixo, I. O., Grandinetti, V. S., Casalechi, H. L., de Carvalho, Paulo de Tarso, C., & Leal, E. C. P. (2016). Photobiomodulation therapy improves performance and accelerates recovery of high-level rugby players in field test: A randomized, crossover, double-blind, placebo-controlled clinical study. Journal of Strength and Conditioning Research, 30(12), 3329-3338. https://doi.org/10.1519/JSC.0000000000001439
6. Wang, Z., Tian, T., Chen, L., Zhang, C., Zheng, X., Zhong, N., Wu, B., & Xu, W. (2023). 980 nm photobiomodulation promotes Osteo/Odontogenic differentiation of the stem cells from human exfoliated deciduous teeth via the Cross talk between BMP/Smad and Wnt/β‐Catenin signaling pathways. Photochemistry and Photobiology, 99(4), 1181-1192. https://doi.org/10.1111/php.13751
7. Yang, J., Wang, L., & Wu, M. X. (2020). 830 nm photobiomodulation therapy promotes engraftment of human umbilical cord blood-derived hematopoietic stem cells. Scientific Reports, 10(1), 19671-19671. https://doi.org/10.1038/s41598-020-76760-5
8. https://www.cdc.gov/mmwr/volumes/72/wr/mm7215a1.htm
9. Yang, J., Wang, L., & Wu, M. X. (2020). 830 nm photobiomodulation therapy promotes engraftment of human umbilical cord blood-derived hematopoietic stem cells. Scientific Reports, 10(1), 19671-19671. https://doi.org/10.1038/s41598-020-76760-5

Hamblin, M. R. (2018). Photobiomodulation for traumatic brain injury and stroke. Journal of Neuroscience Research, 96(4), 731-743. https://doi.org/10.1002/jnr.24190