Photobiomodulation or Light Therapy for Inflammation and Pain

Photobiomodulation (PBM) is an important tool to consider when managing inflammation and pain. While light therapy has been used for over 50 years, it has recently become available commercially and even more recently has become affordable and accessible for individual use. As inflammation and pain are implicated in a variety of conditions, and medications, alone, do not cure these conditions, other therapies are important to consider. Red and infrared low-level light therapy have been used in over 5000 research studies as a therapy to reduce inflammation and pain.

Studies have supported the application of photobiomodulation to include not only lasers, but light-emitting diodes, other light sources, and the range of wavelengths include many in the red and near-infrared. [i] Whereas PBM was once considered a fake or “snake oil” therapy, newer research has proven its value as a therapy.[ii] It has been used for wound healing, weight loss, skin anti-aging, osteoarthritis pain, neurological disorders, as well as a number of other conditions where inflammation is present.[iii] As a therapy, it is used to reduce pain, inflammation, edema, dementia, mental health conditions, cancer side-effects, opioid addiction, and to regenerate damaged tissues such as wounds, bones, and tendons.[iv],[v],[vi] PBM research supports its efficacy in managing arthritis pain, dental pain, Hashimoto’s Thyroiditis, hair loss, wrinkles, and other signs of skin damage. [vii]^{, [viii],[ix],[x],[xi],[xii]}

Red light therapy and infra-red therapy is also called low-level laser therapy (LLLT), low-power laser therapy (LPLT), and photobiomodulation (PBM). PBM is the newer accepted terminology. It works through 2 key mechanisms. First by stimulating the mitochondria, or your energy powerhouses within your cells. Secondly, through creating hormesis, or transient stress on the mitochondria, similar to how exercise functions to build muscle. This transient stress creates a low-level inflammatory response, activating our internal cellular antioxidant and anti-inflammation defense systems, which then, decreases inflammation.

As an application for skin, PBM can help to manage skin pigmentation, heal burns, and address skin conditions such as psoriasis and acne scarring.[xiii] It can stimulate collagen to reduce fine wrinkles. Both red and near-infrared lights penetrate tissue, which makes these lights useful for healing tissue and are the most well-studied light frequencies.

Red light therapy may be delivered via laser or light sources such as light-emitting diodes (LEDs). LEDs have become common with advantages over lasers given that there are no laser safety considerations, ease of home use, ability to irradiate a large area of tissue at once, as well as the possibility of wearable devices, and much lower cost. [xiv] Therapy with light therapy via LED or laser differs. While laser therapy can deliver pinpoint accuracy, LEDs cover a wider angle, although, this means, they lose the energy of the light beam as the light travels. While the delivery systems differ, a study demonstrated that given the equal doses of light, laser and LED were comparable in measures of wound healing.[xv]

Principles of time, shielding, and distance apply to all forms of light irradiation. This means that the time you are exposed to the light source, any shielding (structures, clothes, or other obstacles that are able to shield the specific light form(s), or distance (proximity to device) are important to consider. While red light delivers light primarily to the surface of the skin, infra-red light penetrates the skin surface deeper. Red light is visible, although infra-red is not.

When choosing a LED device for home use of LED red and near-infrared light is generally considered safe. However, more light is not always better (remember that the principle of time of exposure is important), and manufacturer instructions should be followed with device use. Beam angles may differ, which affects the light delivery. Also, the size of light-emitting units varies. Smaller devices essentially cover smaller areas. Full-sized panels can be used for covering broader areas of the body. As manufacturers differ, it is recommended to consider factors such as treatment coverage (the size of panels available), the light irradiance (amount of energy from the light absorbed), light frequency (mixed infrared/red or single light source), quality of the product (how devices are tested), and customer reviews.

In summary, PBM therapy has a growing body of research to support its ability to decrease inflammation and pain in a variety of conditions. Despite the relative safety of LEDs, you should always consult your medical provider before using PBM.

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[i] Chung, H., Dai, T., Sharma, S.K. et al. The Nuts and Bolts of Low-level Laser (Light) Therapy. Ann Biomed Eng 40, 516–533 (2012). https://doi.org/10.1007/s10439-011-0454-7

[ii] Hamblin MR. Photobiomodulation or low-level laser therapy. J Biophotonics. 2016;9(11-12):1122-1124. doi:10.1002/jbio.201670113

[iii] Metin R, Tatli U, Evlice B. Effects of low-level laser therapy on soft and hard tissue healing after endodontic surgery. Lasers Med Sci. 2018;33(8):1699-1706. doi:10.1007/s10103-018-2523-8

[iv] Hamblin MR. Mechanisms and Mitochondrial Redox Signaling in Photobiomodulation. Photochem Photobiol. 2018;94(2):199-212. doi:10.1111/php.12864

[v] Berman MH, Nichols TW. Treatment of Neurodegeneration: Integrating Photobiomodulation and Neurofeedback in Alzheimer’s Dementia and Parkinson’s: A Review. Photobiomodul Photomed Laser Surg. 2019;37(10):623-634. doi:10.1089/photob.2019.4685

[vi] Schiffer F. Unilateral transcranial photobiomodulation for opioid addiction in a clinical practice: A clinical overview and case series. J Psychiatr Res. 2021;133:134-141. doi:10.1016/j.jpsychires.2020.12.004

[vii] Stelian J, Gil I, Habot B,Rosenthal M, Abramovici I,Kutok N, Khahil A. Improvement of Pain and Disability in Elderly Patients with Degenerative Osteoarthritis of the Knee Treated with Narrow-Band Light Therapy. Journal of the American Geriatrics Society, First published: January 1992 https://doi.org/10.1111/j.1532-5415.1992.tb01824.x

[viii] Daigo Y, Daigo E, Fukuoka H, Fukuoka N, Ishikawa M, Takahashi K. Wound Healing and Cell Dynamics Including Mesenchymal and Dental Pulp Stem Cells Induced by Photobiomodulation Therapy: An Example of Socket-Preserving Effects after Tooth Extraction in Rats and a Literature Review. Int J Mol Sci. 2020;21(18):6850. Published 2020 Sep 18. doi:10.3390/ijms21186850

[ix] Solmaz H, Dervisoglu S, Gulsoy M, Ulgen Y. Laser biostimulation of wound healing: bioimpedance measurements support histology. Lasers Med Sci. 2016;31(8):1547-1554. doi:10.1007/s10103-016-2013-9

[x] Yang K, Tang Y, Ma Y, et al. Hair Growth Promoting Effects of 650 nm Red Light Stimulation on Human Hair Follicles and Study of Its Mechanisms via RNA Sequencing Transcriptome Analysis. Ann Dermatol. 2021;33(6):553-561. doi:10.5021/ad.2021.33.6.553

[xi] Gendron DJ, Hamblin MR. Applications of Photobiomodulation Therapy to Musculoskeletal Disorders and Osteoarthritis with Particular Relevance to Canada. Photobiomodul Photomed Laser Surg. 2019;37(7):408-420. doi:10.1089/photob.2018.4597

[xii] Ercetin C, Sahbaz NA, Acar S, Tutal F, Erbil Y. Impact of Photobiomodulation on T3/T4 Ratio and Quality of Life in Hashimoto Thyroiditis. Photobiomodul Photomed Laser Surg. 2020;38(7):409-412. doi:10.1089/photob.2019.4740

[xiii] Avci P, Gupta A, Sadasivam M, et al. Low-level laser (light) therapy (LLLT) in skin: stimulating, healing, restoring. Semin Cutan Med Surg. 2013;32(1):41-52.

[xiv] Heiskanen V, Hamblin MR. Photobiomodulation: lasers vs. light emitting diodes? [published correction appears in Photochem Photobiol Sci. 2018 Oct 31;18(1):259-259]. Photochem Photobiol Sci. 2018;17(8):1003-1017. doi:10.1039/c8pp90049c

[xv] Spitler R, Berns MW. Comparison of laser and diode sources for acceleration of in vitro wound healing by low-level light therapy. J Biomed Opt. 2014;19(3):38001. doi:10.1117/1.JBO.19.3.038001

References:

Whitten, Ari. The Ultimate Guide to Red Light Therapy. Archangel Inc., 2018.