LED Light Therapy

. Author manuscript; available in PMC 2018 May 1.
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Infrared (IR) is a type of electromagnetic radiation, including wavelengths between the 780 nm to 1000 μm. IR is divided into different bands: Near-Infrared (NIR, 0.78~3.0 μm), Mid-Infrared (MIR, 3.0~50.0 μm) and Far-Infrared (FIR, 50.0~1000.0 μm) as defined in standard ISO 20473:2007 Optics and photonics — Spectral bands []. Several studies have reported that IR can improve the healing of skin wounds, photoprevention, relieve pain, stiffness, fatigue of rheumatoid arthritis, ankylosing spondylitis, potentiate photodynamic therapy, treat ophthalmic, neurological, and psychiatric disorders, and stimulate the proliferation of mesenchymal and cardiac stem cells [].

Low-level light therapy (LLLT) is defined as “Treatment using irradiation with light of low power intensity so that the effects are a response to the light and not due to heat. A variety of light sources, especially low-power lasers are used.” in the Medical Subject Headings (MeSH) Descriptor Data 2017. Photobiomodulation (PBM) therapy is “A form of light therapy that utilizes non-ionizing forms of light sources, including lasers, LEDs, and broadband light, in the visible and infrared spectrum. It is a nonthermal process involving endogenous chromophores eliciting photophysical (i.e., linear and nonlinear) and photochemical events at various biological scales. This process results in beneficial therapeutic outcomes including but not limited to the alleviation of pain or inflammation, immunomodulation, and pro-motion of wound healing and tissue regeneration.” as a defined in Anders et al. []. It is now agreed that “PBM therapy” is a more accurate and specific term for the therapeutic application of low-level light compared with “LLLT”.


PMID: 29199384

DOI: 10.1007/s10103-017-2399-z


The objective of this study was to evaluate the effects of LED on burns healing. Five patients with skin burns were submitted to photobiomodulation by LED, GaAsIP diode, (λ 658 nm) with 40 mW, 7 J/cm2 on every other day. Biopsies of burned skin were performed and the healing process was photographed. Patients with bilateral burns were used as self-control, having one limb being irradiated and the contralateral limb irradiated with placebo. The burns treated with LED showed higher epithelization, with keratinocytes and fibroblasts proliferation, increased collagen synthesis, decreased pain, and pruritus. In conclusion, there was a faster clinical improvement in the irradiated limbs.

Holanda VM, Chavantes MC, Wu X, Anders JJ. The mechanistic basis for photobiomodulation therapy of neuropathic pain by near infrared laser light. Lasers Surg Med. 2017;49(5):516–524. doi:10.1002/lsm.22628


Background and objective: Various irradiances have been reported to be beneficial for the treatment of neuropathic pain with near infrared light. However, the mechanistic basis for the beneficial outcomes may vary based on the level of irradiance or fluence rate used. Using in vivo and in vitro experimental models, this study determined the mechanistic basis of photobiomodulation therapy (PBMT) for the treatment of neuropathic pain using a high irradiance.

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PMID: 27943458

DOI: 10.1111/phpp.12282 


The innumerable intricacies associated with chronic wounds have made the development of new painless, noninvasive, biophysical therapeutic interventions as the focus of current biomedical research. Red and near-infrared light-induced photobiomodulation therapy appears to emerge as a promising drug-free approach for promoting wound healing, reduction in inflammation, pain and restoration of function owing to penetration power in conjunction with their ability to positively modulate the biochemical and molecular responses. This review will describe the physical properties of red and near-infrared light and their interaction with skin and highlight their efficacy of wound repair and regeneration. Near-infrared (800-830 nm) was found to be the most effective and widely studied wavelength range followed by red (630-680 nm) and 904 nm superpulsed light exhibiting beneficial photobiomodulatory effects on impaired dermal wound healing.



Objective: The purpose of this study was to review available literature about the effect of photobiomodulation (PBM) on mesenchymal stem cells (MSCs).

Background data: The effects of coherent and noncoherent light sources such as low-level lasers and light-emitting diodes (LEDs) on cells and tissues, known as PBM, form the basis of photomedicine. This treatment technique effects cell function, proliferation, and migration, and plays an important role in tissue regeneration. Stem cells have been found to be helpful elements in tissue regeneration, and the combination of stem cell therapy and laser therapy appears to positively affect treatment results.

Materials and methods: An electronic search in PubMed was conducted of publications from the previous 12 years. English language articles related to the subject were found using selected key words. The full texts of potentially suitable articles were assessed according to inclusion and exclusion criteria.

Results: After evaluation, 30 articles were deemed relevant according to the inclusion criteria. The energy density of the laser was 0.7–9 J/cm2. The power used for visible light was 30–110 mW and that used for infrared light was 50–800 mW. Nearly all studies showed that low-level laser therapy had a positive effect on cell proliferation. Similar outcomes were found for LED; however, some studies suggest that the laser alone is not effective, and should be used as an adjunct tool. Conclusions: PBM has positive effects on MSCs. This review concluded that doses of 0.7–4 J/cm2 and wavelengths of 600–700 nm are appropriate for light therapy. The results were dependent upon different parameters; therefore, optimization of parameters used in light therapy to obtain favorable results is required to provide more accurate comparison.

Light in the red to near-infrared (NIR) range (630&#x2013;1000&#x2009;nm), which is generated using low energy laser or light-emitting diode (LED) arrays, was reported to have a range of beneficial biological effects in many injury models. NIR via a LED is a well-accepted therapeutic tool for the treatment of infected, ischemic, and hypoxic wounds as well as other soft tissue injuries in humans and animals. This study examined the effects of exposure to 660&#x2009;nm red LED light at intensities of 2.5, 5.5, and 8.5&#x2009;mW/cm<sup>2</sup> for 5, 10, and 20&#x2009;min on wound healing and proliferation in fibroblast-like cells, such as L929 mouse fibroblasts and human gingival fibroblasts (HGF-1). A photo illumination-cell culture system was designed to evaluate the cell proliferation and wound healing of fibroblast-like cells exposed to 600&#x2009;nm LED light. The cell proliferation was evaluated by MTT assay, and a scratched wound assay was performed to assess the rate of migrating cells and the healing effect. Exposure to the 660&#x2009;nm red LED resulted in an increase in cell proliferation and migration compared to the control, indicating its potential use as a phototherapeutic agent.

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Howard B Cotler,1,2 Roberta T Chow,3 Michael R Hamblin4,5,6

1Gulf Coast Spine Care LTD, USA
2Laser Health Spa LLC, USA
3Brain and Spine Research Institute, University of Sydney, Australia
4Wellman Center for Photo medicine, Massachusetts General Hospital, USA
5Department of Dermatology, Harvard Medical School, USA
6Division of Health Sciences and Technology, USA

Correspondence: Howard B Cotler, Owner and Medical Director, Laser Health Spa LLC, 1200 Binz Street, Suite 970 Houston, Texas, USA 77004, Tel 713-523-8884

Received: May 21, 2015 | Published: June 9, 2015

Citation: Cotler HB, Chow RT, Hamblin MR. The use of Low Level Laser Therapy (LLLT) for musculoskeletal pain. MOJ Orthop Rheumatol. 2015;2(5):188-194. DOI: 10.15406/mojor.2015.02.00068

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The objective of the present study was to assess the degree of pain relief obtained by applying infrared (IR) energy to the low back in patients with chronic, intractable low back pain.


Forty patients with chronic low back pain of over six years’ duration were recruited from patients attending the Rothbart Pain Management Clinic, North York, Ontario. They came from the patient lists of three physicians at the clinic, and were randomly assigned to IR therapy or placebo treatment. One patient dropped out of the placebo group; as a result, 21 patients received IR therapy and 18 recieved placebo therapy. The IR therapy was provided by two small, portable units in a sturdy waistband powered by small, rechargeable batteries made by MSCT Infrared Wraps Inc (Canada). These units met safety standards for Food and Drug Administration portability, and are registered with the Food and Drug Administration as a therapeutic device. The unit converted electricity to IR energy at 800 nm to 1200 nm wavelength. The treated group received IR therapy. The placebo group had identical units, but the power was not connected to the circuit-board within the IR pad. Patients attended seven weekly sessions. One baseline and six weekly sets of values were recorded. The principle measure of outcome was pain rated on the numerical rating scale (NRS). The pain was assessed overall, then rotating and bending in different directions.


The mean NRS scores in the treatment group fell from 6.9 of 10 to 3 of 10 at the end of the study. The mean NRS in the placebo group fell from 7.4 of 10 to 6 of 10.


The IR therapy unit used was demonstrated to be effective in reducing chronic low back pain, and no adverse effects were observed.

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Harry T. Whelan, Robert L. SmitsJr., Ellen V. Buchman, Noel T. Whelan, Scott G. Turner, David A. Margolis, Vita Cevenini, Helen Stinson, Ron Ignatius, Todd Martin, Joan Cwiklinski, Alan F. Philippi, William R. Graf, Brian Hodgson, Lisa Gould, Mary Kane, Gina Chen, and James Caviness.Journal of Clinical Laser Medicine & Surgery.Dec 2001.305-314.

Published in Volume: 19 Issue 6: July 8, 2004


Objective: The purpose of this study was to assess the effects of hyperbaric oxygen (HBO) and near-infrared light therapy on wound healing.

Background data: Light-emitting diodes (LED), originally developed for NASA plant growth experiments in space show promise for delivering light deep into tissues of the body to promote wound healing and human tissue growth. In this paper, we review and present our new data of LED treatment on cells grown in culture, on ischemic and diabetic wounds in rat models, and on acute and chronic wounds in humans.

Materials and methods: In vitro and in vivo (animal and human) studies utilized a variety of LED wavelength, power intensity, and energy density parameters to begin to identify conditions for each biological tissue that are optimal for biostimulation.

Results: LED produced in vitro increases of cell growth of 140-200% in mouse-derived fibroblasts, rat-derived osteoblasts, and rat-derived skeletal muscle cells, and increases in growth of 155-171% of normal human epithelial cells. Wound size decreased up to 36% in conjunction with HBO in ischemic rat models. LED produced improvement of greater than 40% in musculoskeletal training injuries in Navy SEAL team members, and decreased wound healing time in crew members aboard a U.S. Naval submarine. LED produced a 47% reduction in pain of children suffering from oral mucositis.

Conclusion: We believe that the use of NASA LED for light therapy alone, and in conjunction with hyperbaric oxygen, will greatly enhance the natural wound healing process, and more quickly return the patient to a preinjury/illness level of activity. This work is supported and managed through the NASA Marshall Space Flight Center-SBIR Program.