Mobile Cover ImageClinical Studies on photobiomodulation

Vitenskapelige studier


These are some of the selected studies that highlight the effects of red and near-infrared therapy in the most effective way.

Photobiomodulation therapy (red/NIR LEDs) reduced the length of stay in intensive care unit for patients and improved muscle function: A randomized, triple-blind, and sham-controlled trial

Raimundo Pereira Miranda Neto, Lara Maria Bataglia Espósito, Francisco Costa da Rocha, Antônio Anchieta Sousa Filho, Jefferson Hermann Gomes Silva, Eulália Caroline de Sousa Santos, Bruna Lorena Soares Cavalcante Sousa, Ketlhen Ravena Rodrigues dos Santos Gonçalves, Adriana Sanches Garcia-Araujo, Michael R. Hamblin, Cleber Ferraresi


Photobiomodulation therapy (PBMT) has been widely used to improve strength, fatigue resistance and increase muscle mass in healthy individuals. These effects could help critically ill patients admitted to intensive care units (ICUs) who show reduced mobility and muscle strength. ICU-acquired weakness lessens overall health and increases the patient’s length of stay in the ICU.

This study evaluated the effects of PBMT using low intensity light-emitting diodes (LEDs) on the mobility and muscle strength (functional capacity) and length of stay of patients admitted to hospital ICU.

This randomized, triple-blind, sham-controlled trial was conducted in a hospital ICU. Sixty patients were randomly assigned to two equal groups: (a) PBMT and (b) Sham. PBMT was applied daily to patients until their discharge from the ICU, using a flexible neoprene array of 264 LEDs (120 at 635 nm, 1.2 mW each; 144 at 880 nm, 15 mW each) for 90s (207.36 Joules) at each site. Ten sites were located bilaterally on the thighs, legs, arms, and forearms ventrally and dorsally, 15 min totaling 2,073.6 Joules per session. Outcomes were length of stay (in h) until discharge from the ICU, muscle strength by the Medical Research Council (MRC) score and handgrip dynamometry (HGD), patient mobility by Intensive Care Unit Mobility Scale (IMS) and the Simplified Acute Physiology Score 3 (SAPS 3) for predicting mortality of patients admitted to the ICU.

PBMT reduced the average length of stay in the ICU by ~30% (p = 0.028); increased mobility (IMS: 255% vs. 110% p = 0.007), increased muscle strength (MRC: 12% vs. −9% p = 0.001) and HGD (34% vs. −13% p < 0.001), and the SAPS3 score was similar (p > 0.05).

The results suggest that daily PBMT can reduce the length of stay of ICU patients and increase muscle strength and mobility.

Muscular pre-conditioning using light-emitting diode therapy (LEDT) for high-intensity exercise: a randomized double-blind placebo-controlled trial with a single elite runner

by Cleber Ferraresi, Thomas Beltrame, Fernando Fabrizzi, Eduardo Sanches Pereira do Nascimento, Marlus Karsten, Cristina de Oliveira Francisco, Audrey Borghi-Silva, Aparecida Maria Catai, Daniel Rodrigues Cardoso, Antonio Gilberto Ferreira, Michael R Hamblin, Vanderlei Salvador Bagnato, Nivaldo Antonio Parizotto

Abstract: Recently, low-level laser (light) therapy (LLLT) has been used to improve muscle performance. This study aimed to evaluate the effectiveness of near-infrared light-emitting diode therapy (LEDT) and its mechanisms of action to improve muscle performance in an elite athlete. The kinetics of oxygen uptake (VO2), blood and urine markers of muscle damage (creatine kinase–CK and alanine), and fatigue (lactate) were analyzed. Additionally, some metabolic parameters were assessed in urine using proton nuclear magnetic resonance spectroscopy ((1)H NMR). A LED cluster with 50 LEDs (λ = 850 nm; 50 mW 15 s; 37.5 J) was applied on legs, arms and trunk muscles of a single runner athlete 5 min before a high-intense constant workload running exercise on treadmill. The athlete received either Placebo-1-LEDT; Placebo-2-LEDT; or Effective-LEDT in a randomized double-blind placebo-controlled trial with washout period of 7 d between each test.

Key points:

  • LEDT improved the speed of the muscular VO2 adaptation (∼-9 s), decreased O2 deficit (∼-10 L), increased the VO2 from the slow component phase (∼+348 ml min(-1)), and increased the time limit of exercise (∼+589 s).
  • LEDT decreased blood and urine markers of muscle damage and fatigue (CK, alanine and lactate levels).
  • The results suggest that a muscular pre-conditioning regimen using LEDT before intense exercises could modulate metabolic and renal function to achieve better performance.

Effect of 830 nm low-level laser therapy applied before high-intensity exercises on skeletal muscle recovery in athletes

by Ernesto Cesar Pinto Leal Junior, Rodrigo Alvaro Brandão Lopes-Martins, Bruno Manfredini Baroni, Thiago De Marchi, Daiana Taufer, Débora Sgandella Manfro, Morgana Rech, Vanessa Danna, Douglas Grosselli, Rafael Abeche Generosi, Rodrigo Labat Marcos, Luciano Ramos, Jan Magnus Bjordal

Abstract: Our aim was to investigate the immediate effects of bilateral, 830 nm, low-level laser therapy (LLLT) on high-intensity exercise and biochemical markers of skeletal muscle recovery, in a randomised, double-blind, placebo-controlled, crossover trial set in a sports physiotherapy clinic. Twenty male athletes (nine professional volleyball players and eleven adolescent soccer players) participated. Active LLLT (830 nm wavelength, 100 mW, spot size 0.0028 cm(2), 3-4 J per point) or an identical placebo LLLT was delivered to five points in the rectus femoris muscle (bilaterally). The main outcome measures were the work performed in the Wingate test: 30 s of maximum cycling with a load of 7.5% of body weight, and the measurement of blood lactate (BL) and creatine kinase (CK) levels before and after exercise.

Key points:

  • There was no significant difference in the work performed during the Wingate test (P > 0.05) between subjects given active LLLT and those given placebo LLLT.
  • For volleyball athletes, the change in CK levels from before to after the exercise test was significantly lower (P = 0.0133) for those given active LLLT (2.52 U l(-1) +/- 7.04 U l(-1)) than for those given placebo LLLT (28.49 U l(-1) +/- 22.62 U l(-1)).
  • For the soccer athletes, the change in blood lactate levels from before exercise to 15 min after exercise was significantly lower (P < 0.01) in the group subjected to active LLLT (8.55 mmol l(-1) +/- 2.14 mmol l(-1)) than in the group subjected to placebo LLLT (10.52 mmol l(-1) +/- 1.82 mmol l(-1)).
  • LLLT irradiation before the Wingate test seemed to inhibit an expected post-exercise increase in CK level and to accelerate post-exercise lactate removal without affecting test performance. These findings suggest that LLLT may be of benefit in accelerating post-exercise recovery

Photobiomodulation therapy as a tool to prevent hamstring strain injuries by reducing soccer-induced fatigue on hamstring muscles

Maurício Pinto Dornelles, Carolina Gassen Fritsch, Francesca Chaida Sonda, Douglas Scott Johnson, Ernesto Cesar Pinto Leal-Junior, Marco Aurélio Vaz, Bruno Manfredini Baroni

Abstract: Muscle fatigue is a potential risk factor for hamstring strain injuries in soccer players. The aim of this study was to verify the effect of photobiomodulation therapy (PBMT) on the hamstrings’ muscle fatigue of soccer players during a simulated match. Twelve male amateur soccer players (~ 25 years) participated in this randomized, crossover, double-blinded, placebo-controlled trial. The volunteers were evaluated in two sessions, with a minimum 7-day interval. At each session, volunteers received either PBMT (300 J per thigh) or placebo treatment on the hamstrings prior to the simulated soccer match. Muscle strength and functional capacity were evaluated through isokinetic dynamometry and countermovement jump (CMJ) tests, respectively, before and immediately after the simulated soccer match. Players had lower reductions on hamstring eccentric peak torque [4.85% (ES = 0.31) vs. 8.72% (ES = 0.50)], hamstring-to-quadriceps torque ratio [3.60% (ES = 0.24) vs. 7.75% (ES = 0.50)], and CMJ height [1.77% (ES = 0.09) vs. 5.47% (ES = 0.32)] when treated with PBMT compared to placebo. Magnitude-based inference supports that PBMT promoted 75%, 69%, and 53% chances for beneficial effects on hamstring eccentric peak torque, hamstring-to-quadriceps torque ratio, and CMJ height, respectively, compared to placebo treatment.

Conclusion: In conclusion, PBMT applied before a simulated soccer match proved to be effective in attenuating the hamstrings’ muscle fatigue. These findings support PBMT as a promising tool to prevent hamstring strain injury in soccer players.

When is the best moment to apply photobiomodulation therapy (PBMT) when associated to a treadmill endurance-training program? A randomized, triple-blinded, placebo-controlled clinical trial

by Eduardo Foschini Miranda, Shaiane Silva Tomazoni, Paulo Roberto Vicente de Paiva, Henrique Dantas Pinto, Denis Smith, Larissa Aline Santos, Paulo de Tarso Camillo de Carvalho, Ernesto Cesar Pinto Leal-Junior

Abstract: Photobiomodulation therapy (PBMT) employing low-level laser therapy (LLLT) and/or light emitting diode therapy (LEDT) has emerged as an electrophysical intervention that could be associated with aerobic training to enhance beneficial effects of aerobic exercise. However, the best moment to perform irradiation with PBMT in aerobic training has not been elucidated. The aim of this study was to assess the effects of PBMT applied before and/or after each training session and to evaluate outcomes of the endurance-training program associated with PBMT. Seventy-seven healthy volunteers completed the treadmill-training protocol performed for 12 weeks, with 3 sessions per week. PBMT was performed before and/or after each training session (17 sites on each lower limb, using a cluster of 12 diodes: 4 × 905 nm super-pulsed laser diodes, 4 × 875 nm infrared LEDs, and 4 × 640 nm red LEDs, dose of 30 J per site). Volunteers were randomized in four groups according to the treatment they would receive before and after each training session: PBMT before + PBMT after, PBMT before + placebo after, placebo before + PBMT after, and placebo before + placebo after. Assessments were performed before the start of the protocol and after 4, 8, and 12 weeks of training. Primary outcome was time until exhaustion; secondary outcome measures were oxygen uptake and body fat.

Key points:

  • PBMT applied before and after aerobic exercise training sessions (PBMT before + PBMT after group) significantly increased (p < 0.05) the percentage of change of time until exhaustion and oxygen uptake compared to the group treated with placebo before and after aerobic exercise training sessions (placebo before + placebo after group) at 4th, 8th, and 12th week.
  • PBMT applied before and after aerobic exercise training sessions (PBMT before + PBMT after group) also significantly improved (p < 0.05) the percentage of change of body fat compared to the group treated with placebo before and after aerobic exercise training sessions (placebo before + placebo after group) at 8th and 12th week.
  • PBMT applied before and after sessions of aerobic training during 12 weeks can increase the time-to-exhaustion and oxygen uptake and also decrease the body fat in healthy volunteers when compared to placebo irradiation before and after exercise sessions.

Conclusion: Our outcomes show that PBMT applied before and after endurance-training exercise sessions lead to improvement of endurance three times faster than exercise only.

Photobiomodulation Therapy Combined with Static Magnetic Field Reduces Pain in Patients with Chronic Nonspecific Neck and/or Shoulder Pain: A Randomized, Triple-Blinded, Placebo-Controlled Trial

by Adeilson Matias Teixeira, Ernesto Cesar Pinto Leal-Junior, Heliodora Leão Casalechi, Adriane Aver Vanin, Paulo Roberto Vicente de Paiva, Fernando Hess Câmara Melo, Douglas Scott Johnson and Shaiane Silva Tomazoni

Abstract: Photobiomodulation therapy (PBMT) has been used to treat patients with chronic neck and/or shoulder pain. However, it is unknown whether the concurrent use of PBMT and static magnetic field (PBMT-sMF) also has positive effects in these patients. The aim of this study was to investigate the effects of PBMT-sMF versus placebo on pain intensity, range of motion (ROM) and treatment satisfaction in patients with chronic nonspecific neck and/or shoulder pain.

Key points:

  • A randomized controlled trial, with blinded assessors, therapists and patients was carried out.
  • Seventy-two patients with chronic nonspecific neck and/or shoulder pain were randomized to either active PBMT-sMF (n = 36) or placebo PBMT-sMF (n = 36).
  • Patients were treated twice weekly, over 3 weeks.
  • Primary outcome was pain intensity, measured 15 min after the last treatment session and at 24-, 48-, 72-h, and 7-days after the last treatment.
  • Secondary outcomes were ROM, patient’ treatment satisfaction, and adverse effects.
  • PBMT-sMF was able to reduce pain intensity in all time points tested compared to placebo (p < 0.05). There was no difference between groups in the secondary outcomes (p > 0.05). Our results suggest that PBMT-sMF is better than placebo to reduce pain in patients with chronic nonspecific neck and/or shoulder pain at short-term.

Light stimulation of mitochondria reduces blood glucose levels

Michael B. Powner, Glen Jeffery

Abstract: Mitochondria regulate metabolism, but solar light influences its rate. Photobiomodulation (PBM) with red light (670 nm) increases mitochondrial membrane potentials and adenosine triphosphate production and may increase glucose demand.

Conclusion: Here we show, with a glucose tolerance test, that PBM of normal subjects significantly reduces blood sugar levels. A 15 min exposure to 670 nm light reduced the degree of blood glucose elevation following glucose intake by 27.7%, integrated over 2 h after the glucose challenge. Maximum glucose spiking was reduced by 7.5%. Consequently, PBM with 670 nm light can be used to reduce blood glucose spikes following meals. This intervention may reduce damaging fluctuations of blood glucose on the body.

Pain and Inflammation Relief

When using correct wavelengths and dosages, near-infrared therapy has excellent pain relief effects. Some of the mechanisms behind these pain relief properties are due to inflammation reduction, but others use entirely different pathways. Here are some of the most significant studies on the topic.

Effectiveness of Photobiomodulation Therapy in the Treatment of Myofascial Pain Syndrome of the Upper Trapezius Muscle: A Systematic Review and Meta-Analysis

Alayat MSM, Battecha KH, Elsodany AM, Alzahrani OA, Alqurashi AKA, Jawa AT, Alharthi YS


Objective: This systematic review aimed to investigate the efficacy of photobiomodulation therapy (PBMT) on pain and pressure pain threshold (PPT) in patients with myofascial pain syndrome (MPS) of the upper trapezius muscle.

Materials and methods: A total of 17 studies (944 patients) were included; data regarding participants, intervention parameters, outcome measures, time of measurement, and follow-up were extracted. Evaluation of the methodological quality was performed by Physiotherapy Evidence Database (PEDro) scale. Grading of Recommendations Assessment, Development, and Evaluation (GRADE) system was used to assess the quality of evidence. A meta-analysis was performed on 16 studies, and standardized mean difference (SMD), corresponding 95% confidence interval (CI), and overall effect size (ES) were calculated.

Results: Meta-analysis using a random-effect model was performed to evaluate the effects of PBMT alone or PBMT plus exercise (EX) compared with placebo, medical treatment, physical therapy (PT) modality, manual therapy, or complementary PT. Assessment according to the PEDro scale revealed 12 high-quality, 3 fair-quality, and 2 low-quality studies. According to the GRADE system, studies exhibited low to medium quality of evidence, with medium ES [SMD −0.54 (95% CI −1.05 to −0.02)] for studies using PBMT alone and large ES [SMD −0.80 (95% CI −1.35 to −0.26)] for PBMT+EX.

Conclusions: The present systemic review revealed that PBMT is an effective PT modality for reducing pain and increasing PPT in patients with MPS of the upper trapezius. PBMT, when combined with EX, had more significant effects in reducing pain and increasing PPT compared with controls. The low-quality studies with low to moderate quality of evidence limit the confidence in the effect estimate and recommend further high-quality studies for standardization of treatment protocols and irradiation parameters.

Feasibility study of a LED light irradiation device for the treatment of chronic neck with shoulder muscle pain/stiffness

Keiichi Odagiri ,Katsuya Yamauchi,Masahiro Toda,Ayako Uchida,Hiromi Tsubota,Kazuyoshi Zenba,Hiroaki Okawai,Hideo Eda,Seiichiro Mizuno,Hiroaki Yokota

Abstract: Neck with shoulder muscle stiffness/pain is a common disorder. Commonly used physical therapy, pharmacotherapy, acupuncture, and moxibustion only temporarily alleviate the disorder in most cases, thus the disorder often recurs. Low power laser therapy is often used for neck and shoulder stiffness/pain and has been effective in clinical trials. In this study, we evaluated the safety and effectiveness of a newly developed self-care device for disorders including neck with shoulder muscle stiffness/pain. The device incorporates light-emitting diodes (LEDs), which are safer than lasers, as its light source. Ten adults with neck with shoulder muscle stiffness/pain were subject to LED irradiation (wavelength 780 nm ± 15 nm, output 750 mW, power density 3.8 W/cm2, energy density 5.7×102 J/cm2) for 3 minutes on the affected shoulder at a standard acupuncture point (GB21, Jianjing).

Key points:

  • Immediately after irradiation, the subjective symptoms of the neck with shoulder muscle stiffness and pain evaluated by a visual analog scale were improved from 58.3 mm ± 18.7 mm to 45.5 mm ± 21.5 mm and from 45.8 mm ± 23.3 mm to 39.4 mm ± 21.8 mm, respectively. The symptoms further improved after 15 minutes of irradiation.
  • The skin temperature at the irradiated point increased from 34.3°C ± 1.1°C to 41.0°C ± 0.7°C. The increase in skin temperature was observed within approximately 5 cm of the irradiated area.
  • There was no effect on the heart rate variability, a measure of the autonomic nervous system; however, the baroreflex sensitivity was slightly increased.
  • No irradiation-related adverse skin events were observed.
  • Our LED irradiation device was found to be safe, and it improved the subjective symptoms of muscle stiff neck with shoulders.

Photobiomodulation: Implications for Anesthesia and Pain Relief

by Roberta T. Chow, MB, BS (Hons), FRACGP, PhD, and Patricia J. Armati, PhD

Results: Evidence shows that PBM can inhibit nerve function in vivo, in situ, ex vivo, and in culture. Animal studies using noxious stimuli indicate nociceptor-specific inhibition with other studies providing direct evidence of local conduction block, leading to inhibited translation of pain centrally. Evidence of PBM-disrupted neuronal physiology affecting axonal flow, cytoskeleton organization, and decreased ATP is also presented. PBM changes are reversible with no side effects or nerve damage.

Conclusions: This review provides strong evidence in neuroscience identifying inhibition of neural function as a mechanism for the clinical application of PBM in pain and anesthesia

Mechanisms and Pathways of Pain Photobiomodulation: A Narrative Review

Cheng K, Martin LF, Slepian MJ, Patwardhan AM, Ibrahim MM.

Abstract: A growing body of evidence supports the modulation of pain by light exposure. As such, phototherapy is being increasingly utilized for the management of a variety of pain conditions. The modes of delivery, and hence applications of phototherapy, vary by wavelength, intensity, and route of exposure. As such, differing mechanisms of action exist depending upon those parameters. Cutaneous application of red light (660nm) has been shown to reduce pain in neuropathies and complex regional pain syndrome-I, whereas visual application of the same wavelength of red light has been reported to exacerbate migraine headache in patients and lead to the development of functional pain in animal models. Interestingly visual exposure to green light can result in reduction in pain in variety of pain conditions such as migraine and fibromyalgia. Cutaneous application typically requires exposure on the order of minutes, whereas visual application requires exposure on the order of hours. Both routes of exposure elicit changes centrally in the brainstem and spinal cord, and peripherally in the dorsal root ganglia and nociceptors. The mechanisms of photobiomodulation of pain presented in this review provide a foundation in furtherance of exploration of the utility of phototherapy as a tool in the management of pain.

Key points: Cutaneous application of red light (660nm) has been shown to reduce pain in neuropathies and complex regional pain syndrome-I, whereas visual application of the same wavelength of red light has been reported to exacerbate migraine headache in patients and lead to the development of functional pain in animal models.

Low-intensity LASER and LED (photobiomodulation therapy) for pain control of the most common musculoskeletal conditions

by Marcelo F DE Oliveira, Douglas S Johnson, Timothy Demchak, Shaiane S Tomazoni, Ernesto C Leal-Junior

Abstract: Pain is the most common reason for physician consultations and the number one reason for missed work or school days is musculoskeletal pain. Pain management is utilized for easing the suffering and improving the Quality of Life of those living with chronic pain. Over the past several decades, physicians have become increasingly willing to prescribe opioids to manage pain. However, the opioid use can cause side effects as poor coordination, sedation, mood swings, depression, and anxiety combined with a dependence on the drugs. In the rehabilitation setting, patients benefit most when their health providers utilize a multimodal approach combining different types of therapies and when patients take on a significant role in optimal management of their own pain. The use of light as a therapeutic alternative form of medicine to manage pain and inflammation has been proposed to fill this void.

Photobiomodulation therapy applied in the form of low-intensity Light Amplification by Stimulated Emission of Radiation (LASER) and light-emitting diode (LED) has been shown to reduce inflammation and swelling, promote healing, and reduce pain for an array of musculoskeletal conditions.

There is evidence that photobiomodulation therapy reduces pain intensity in non-specific knee pain, osteoarthritis, pain post-total hip arthroplasty, fibromyalgia, temporomandibular diseases, neck pain, and low back pain.

Therefore, the purpose of this paper was to present the up-to-dated evidence about the effects of low-intensity LASER and LED (photobiomodulation therapy) on pain control of the most common musculoskeletal conditions.

Key points: We observed that the photobiomodulation therapy offers a non-invasive, safe, drug-free, and side-effect-free method for pain relief of both acute and chronic musculoskeletal conditions as well as fibromyalgia.

Photobiomodulation with simultaneous use of red and infrared light emitting diodes in the treatment of temporomandibular disorder: study protocol for a randomized, controlled and double-blind clinical trial

Sousa, Dowglas Fernando Magalhães de MS; Gonçalves, Marcela Letícia Leal PhD; Politti, Fabiano PhD; Lovisetto, Renan Didier de Paula Physiotherapist; Fernandes, Kristianne Porta Santos PhD; Bussadori, Sandra Kalil PhD; Mesquita-Ferrari, Raquel Agnelli PhD


Introduction: Temporomandibular disorder (TMD) is considered the main cause of orofacial pain of non-dental origin, and a public health problem. The symptomatology is muscular and/or articular pain, restriction of the mandibular range of motion, and changes in the mandibular movement pattern. Due to its complexity there are already treatments using various forms of therapy. Photobiomodulation using light sources, such as low-level laser or light emitting diodes (LED), with different wavelengths, in a single or combined form, allows one more therapeutic resource to be explored. The objective of this study is to evaluate the effects of photobiomodulation with the simultaneous use of red and infrared LEDs, on pain, range of mandibular movements, and on the electrical activity of masticatory muscles in individuals with TMD.

Methods: A randomized, controlled, double-blind clinical trial is proposed, which will involve 33 individuals (n = 11 per group) of both sexes, ages 18 to 45 years in 3 groups: LED group; placebo group; and control group, submitted to 6 non-consecutive sessions of photobiomodulation totaling 2 weeks of treatment. The Research Diagnostic Criteria for Temporomandibular Disorders—RDC/TMD will be used to assess and determine the participants’ TMD. The pain will be assessed using the Visual Analog Scale – VAS, the mandibular range of motion will be determined with the aid of a digital caliper, and the electrical activity of the masticatory muscles will be verified by electromyography. A mixed plate of 18 red LEDs—660 nm and 18 infrared LEDs—850 nm with power of 3.5 mW per LED, 4.45 mW/cm2, radiant exposure of 5.35 J/cm2, will be used for photobiomodulation. The irradiated area will be 14.13 cm2, and energy of 75.6 J, in the TMJ region and in the bilateral masseter and temporal muscles. Participants from all groups will be reassessed after the first therapeutic intervention, and at the end of treatment.

Discussion: We expect the use of photobiomodulation with LEDs, infra and red, to reduce pain, improve temporomandibular joint function in patients with TMD, and thus improve the general conditions of the patient.

Pain management using photobiomodulation: Mechanisms, location, and repeatability quantified by pain threshold and neural biomarkers in mice

de Sousa MVP, Kawakubo M, Ferraresi C, Kaippert B, Yoshimura EM, Hamblin MR

Abstract: Photobiomodulation (PBM) is a simple, efficient and cost-effective treatment for both acute and chronic pain. We previously showed that PBM applied to the mouse head inhibited nociception in the foot. Nevertheless, the optimum parameters, location for irradiation, duration of the effect and the mechanisms of action remain unclear.

Key points:

  • In the present study, the pain threshold in the right hind paw of mice was studied, after PBM (810 nm CW laser, spot size 1 or 6 cm2, 1.2–36 J/cm2) applied to various anatomical locations.
  • The pain threshold, measured with von Frey filaments, was increased more than 3-fold by PBM to the lower back (dorsal root ganglion, DRG), as well as to other neural structures along the pathway such as the head, neck and ipsilateral (right) paw. On the other hand, application of PBM to the contralateral (left) paw, abdomen and tail had no effect.
  • The optimal effect occurred 2 to 3 hours post-PBM and disappeared by 24 hours. Seven daily irradiations showed no development of tolerance.
  • Type 1 metabotropic glutamate receptors decreased, and prostatic acid phosphatase and tubulin-positive varicosities were increased as shown by immunofluorescence of DRG samples.
  • These findings elucidate the mechanisms of PBM for pain and provide insights for clinical practice.

Muscle Pre-Conditioning

The goal of muscle pre-conditioning is to enhance muscle performance, reduce the risk of injury, and improve recovery. Clinical studies show that photobiomodulation can stimulate cellular processes that lead to improved muscle function and resilience.

Effects of low-level laser therapy on skeletal muscle repair: a systematic review

Alves AN, Fernandes KP, Deana AM, Bussadori SK, Mesquita-Ferrari RA

Abstract: A review of the literature was performed to demonstrate the most current applicability of low-level laser therapy (LLLT) for the treatment of skeletal muscle injuries, addressing different lasers, irradiation parameters, and treatment results in animal models. Searches were performed in the PubMed/MEDLINE, SCOPUS, and SPIE Digital Library databases for studies published from January 2006 to August 2013 on the use of LLLT for the repair of skeletal muscle in any animal model. All selected articles were critically appraised by two independent raters. Seventeen of the 36 original articles on LLLT and muscle injuries met the inclusion criteria and were critically evaluated.

Key points:

  • The main effects of LLLT were a reduction in the inflammatory process, the modulation of growth factors and myogenic regulatory factors, and increased angiogenesis.
  • The studies analyzed demonstrate the positive effects of LLLT on the muscle repair process, which are dependent on irradiation and treatment parameters.
  • The findings suggest that LLLT is an excellent therapeutic resource for the treatment of skeletal muscle injuries in the short-term.

Low-level laser (light) therapy (LLLT) on muscle tissue: performance, fatigue and repair benefited by the power of light

by Cleber Ferraresi, Michael R Hamblin, Nivaldo A Parizotto

Abstract: The use of low level laser (light) therapy (LLLT) has recently expanded to cover areas of medicine that were not previously thought of as the usual applications such as wound healing and inflammatory orthopedic conditions. One of these novel application areas is LLLT for muscle fatigue and muscle injury. Since it is becoming agreed that mitochondria are the principal photoacceptors present inside cells, and it is known that muscle cells are exceptionally rich in mitochondria, this suggests that LLLT should be highly beneficial in muscle injuries. The ability of LLLT to stimulate stem cells and progenitor cells means that muscle satellite cells may respond well to LLLT and help muscle repair. Furthermore the ability of LLLT to reduce inflammation and lessen oxidative stress is also beneficial in cases of muscle fatigue and injury.

Key points: This review covers the literature relating to LLLT and muscles in both preclinical animal experiments and human clinical studies. Athletes, people with injured muscles, and patients with Duchenne muscular dystrophy may all benefit.

Photobiomodulation in human muscle tissue: an advantage in sports performance?

Ferraresi C, Huang YY, Hamblin MR

Abstract: Photobiomodulation (PBM) describes the use of red or near-infrared (NIR) light to stimulate, heal, and regenerate damaged tissue. Both preconditioning (light delivered to muscles before exercise) and PBM applied after exercise can increase sports performance in athletes. This review covers the effects of PBM on human muscle tissue in clinical trials in volunteers related to sports performance and in athletes. The parameters used were categorized into those with positive effects or no effects on muscle performance and recovery. Randomized controlled trials and case-control studies in both healthy trained and untrained participants, and elite athletes were retrieved from MEDLINE up to 2016. Performance metrics included fatigue, number of repetitions, torque, hypertrophy; measures of muscle damage and recovery such as creatine kinase and delayed onset muscle soreness. Searches retrieved 533 studies, of which 46 were included in the review (n = 1045 participants). Studies used single laser probes, cluster of laser diodes, LED clusters, mixed clusters (lasers and LEDs), and flexible LED arrays. Both red, NIR, and red/NIR mixtures were used.

Key points: PBM can increase muscle mass gained after training, and decrease inflammation and oxidative stress in muscle biopsies. We raise the question of whether PBM should be permitted in athletic competition by international regulatory authorities.

Impact on Endurance and Reduction of Fatigue

There is an increasing number of interesting studies all pointing to the fact that photobiomodulation therapy enhances endurance and reduces fatigue by improving mitochondrial function and increasing ATP production.

Infrared Low-Level Laser Therapy (Photobiomodulation Therapy) before Intense Progressive Running Test of High-Level Soccer Players: Effects on Functional, Muscle Damage, Inflammatory, and Oxidative Stress Markers-A Randomized Controlled Trial

Shaiane Silva Tomazoni, Caroline dos Santos Monteiro Machado, Thiago De Marchi, Heliodora Leão Casalechi, Jan Magnus Bjordal, Paulo de Tarso Camillo de Carvalho, and Ernesto Cesar Pinto Leal-Junior

Abstract: The effects of preexercise photobiomodulation therapy (PBMT) to enhance performance, accelerate recovery, and attenuate exercise-induced oxidative stress were still not fully investigated, especially in high-level athletes. The aim of this study was to evaluate the effects of PBMT (using infrared low-level laser therapy) applied before a progressive running test on functional aspects, muscle damage, and inflammatory and oxidative stress markers in high-level soccer players. A randomized, triple-blind, placebo-controlled crossover trial was performed. Twenty-two high-level male soccer players from the same team were recruited and treated with active PBMT and placebo. The order of interventions was randomized. Immediately after the application of active PBMT or placebo, the volunteers performed a standardized high-intensity progressive running test (ergospirometry test) until exhaustion. We analyzed rates of oxygen uptake (VO2 max), time until exhaustion, and aerobic and anaerobic threshold during the intense progressive running test. Creatine kinase (CK) and lactate dehydrogenase (LDH) activities, levels of interleukin-1β (IL-1-β), interleukin-6 (IL-6), and tumor necrosis factor alpha (TNF-α), levels of thiobarbituric acid (TBARS) and carbonylated proteins, and catalase (CAT) and superoxide dismutase (SOD) activities were measured before and five minutes after the end of the test.

Key points:

  • PBMT increased the VO2 max (both relative and absolute values— and , respectively), time until exhaustion (), time () and volume () in which anaerobic threshold happened, and volume in which aerobic threshold happened ().
  • Moreover, PBMT decreased CK () and LDH () activities.
  • Regarding the cytokines, PBMT decreased only IL-6 ().
  • Finally, PBMT decreased TBARS () and carbonylated protein levels () and increased SOD ()and CAT () activities.
  • The findings of this study demonstrate that preexercise PBMT acts on different functional aspects and biochemical markers.
  • Moreover, preexercise PBMT seems to play an important antioxidant effect, decreasing exercise-induced oxidative stress and consequently enhancing athletic performance and improving postexercise recovery. This trial is registered with NCT03803956.

Phototherapy in skeletal muscle performance and recovery after exercise: effect of combination of super-pulsed laser and light-emitting diodes

by Fernanda Colella Antonialli, Thiago De Marchi, Shaiane Silva Tomazoni, Adriane Aver Vanin, Vanessa dos Santos Grandinetti, Paulo Roberto Vicente de Paiva, Henrique Dantas Pinto, Eduardo Foschini Miranda, Paulo de Tarso Camillo de Carvalho, Ernesto Cesar Pinto Leal-Junior

Abstract: Recent studies with phototherapy have shown positive results in enhancement of performance and improvement of recovery when applied before exercise. However, several factors still remain unknown such as therapeutic windows, optimal treatment parameters, and effects of combination of different light sources (laser and LEDs). The aim of this study was to evaluate the effects of phototherapy with the combination of different light sources on skeletal muscle performance and post-exercise recovery, and to establish the optimal energy dose. A randomized, double-blinded, placebo-controlled trial with participation of 40 male healthy untrained volunteers was performed. A single phototherapy intervention was performed immediately after pre-exercise (baseline) maximum voluntary contraction (MVC) with a cluster of 12 diodes (4 of 905 nm lasers-0.3125 mW each, 4 of 875 nm LEDs-17.5 mW each, and 4 of 670 nm LEDs-15 mW each- manufactured by Multi Radiance Medical™) and dose of 10, 30, and 50 J or placebo in six sites of quadriceps. MVC, delayed onset muscle soreness (DOMS), and creatine kinase (CK) activity were analyzed. Assessments were performed before, 1 min, 1, 24, 48, 72, and 96 h after eccentric exercise protocol employed to induce fatigue.

Key points:

  • Phototherapy increased (p < 0.05) MVC was compared to placebo from immediately after to 96 h after exercise with 10 or 30 J doses (better results with 30 J dose).
  • DOMS was significantly decreased compared to placebo (p < 0.05) with 30 J dose from 24 to 96 h after exercise, and with 50 J dose from immediately after to 96 h after exercise.
  • CK activity was significantly decreased (p < 0.05) compared to placebo with all phototherapy doses from 1 to 96 h after exercise (except for 50 J dose at 96 h).
  • Pre-exercise phototherapy with combination of low-level laser and LEDs, mainly with 30 J dose, significantly increases performance, decreases DOMS, and improves biochemical marker related to skeletal muscle damage.

Immediate effects of photobiomodulation therapy combined with a static magnetic field on the subsequent performance: a preliminary randomized crossover triple-blinded placebo-controlled trial

Ivo de Oliveira Aleixo-Junior, Ernesto Cesar Pinto Leal-Junior, Heliodora Leão Casalechi, Adriane Aver Vanin, Paulo Roberto Vicente de Paiva, Caroline dos Santos Monteiro Machado, Luana Barbosa Dias, Matheus Marinho Aguiar Lino, Adeilson Matias Teixeira, Douglas Scott Johnson, and Shaiane Silva Tomazoni

Abstract: There is evidence about the effects of photobiomodulation therapy (PBMT) alone and combined with a static magnetic field (PBMT-sMF) on skeletal muscle fatigue, physical performance and post-exercise recovery in different types of exercise protocols and sports activity. However, the effects of PBMT-sMF to improve the subsequent performance after a first set of exercises are unknown. Therefore, the aim of this study was to investigate the effects of PBMT-sMF, applied between two sets of exercises, on the subsequent physical performance. A randomized, crossover, triple-blinded (assessors, therapist, and volunteers), placebo-controlled trial was carried out. Healthy non-athlete male volunteers were randomized and treated with a single application of PBMT-sMF and placebo between two sets of an exercise protocol performed on isokinetic dynamometer. The order of interventions was randomized. The primary outcome was fatigue index and the secondary outcomes were total work, peak work, and blood lactate levels. Twelve volunteers were randomized and analyzed to each sequence. PBMT-sMF decreased the fatigue index compared to the placebo PBMT-sMF at second set of the exercise protocol (MD = -6.08, 95% CI -10.49 to -1.68). In addition, PBMT-sMF decreased the blood lactate levels post-intervention, and after the second set of the exercise protocol compared to placebo (p<0.05). There was no difference between PBMT-sMF and placebo in the remaining outcomes tested. Volunteers did not report adverse events.

Conclusion: Our results suggest that PBMT-sMF is able to decrease skeletal muscle fatigue, accelerating post-exercise recovery and, consequently, increasing subsequent physical performance when applied between two sets of exercises.

Comparison between cold water immersion therapy (CWIT) and light emitting diode therapy (LEDT) in short-term skeletal muscle recovery after high-intensity exercise in athletes–preliminary results

by Ernesto Cesar Leal Junior, Vanessa de Godoi, José Luis Mancalossi, Rafael Paolo Rossi, Thiago De Marchi, Márcio Parente, Douglas Grosselli, Rafael Abeche Generosi, Maira Basso, Lucio Frigo, Shaiane Silva Tomazoni, Jan Magnus Bjordal, Rodrigo Alvaro Brandão Lopes-Martins

Abstract: In the last years, phototherapy has becoming a promising tool to improve skeletal muscle recovery after exercise, however, it was not compared with other modalities commonly used with this aim. In the present study we compared the short-term effects of cold water immersion therapy (CWIT) and light emitting diode therapy (LEDT) with placebo LEDT on biochemical markers related to skeletal muscle recovery after high-intensity exercise. A randomized double-blind placebo-controlled crossover trial was performed with six male young futsal athletes. They were treated with CWIT (5°C of temperature [SD ±1°]), active LEDT (69 LEDs with wavelengths 660/850 nm, 10/30 mW of output power, 30 s of irradiation time per point, and 41.7 J of total energy irradiated per point, total of ten points irradiated) or an identical placebo LEDT 5 min after each of three Wingate cycle tests. Pre-exercise, post-exercise, and post-treatment measurements were taken of blood lactate levels, creatine kinase (CK) activity, and C-reactive protein (CRP) levels. There were no significant differences in the work performed during the three Wingate tests (p > 0.05). All biochemical parameters increased from baseline values (p < 0.05) after the three exercise tests, but only active LEDT decreased blood lactate levels (p = 0.0065) and CK activity (p = 0.0044) significantly after treatment. There were no significant differences in CRP values after treatments.

Conclusion: We concluded that treating the leg muscles with LEDT 5 min after the Wingate cycle test seemed to inhibit the expected post-exercise increase in blood lactate levels and CK activity. This suggests that LEDT has better potential than 5 min of CWIT for improving short-term post-exercise recovery.

Does Phototherapy Enhance Skeletal Muscle Contractile Function and Postexercise Recovery? A Systematic Review.

by Paul A Borsa, PhD, ATC, FACSM, Kelly A Larkin, PhD, CAT(C), and Jerry M True, DC, FIACN

Context: Recently, researchers have shown that phototherapy administered to skeletal muscle immediately before resistance exercise can enhance contractile function, prevent exercise-induced cell damage, and improve postexercise recovery of strength and function.

Objective: To critically evaluate original research addressing the ability of phototherapeutic devices, such as lasers and light-emitting diodes (LEDs), to enhance skeletal muscle contractile function, reduce exercise-induced muscle fatigue, and facilitate postexercise recovery.

Conclusions: Phototherapy administered before resistance exercise consistently has been found to provide ergogenic and prophylactic benefits to skeletal muscle.

Effect of phototherapy (low-level laser therapy and light-emitting diode therapy) on exercise performance and markers of exercise recovery: a systematic review with meta-analysis

by Ernesto Cesar Pinto Leal-Junior, Adriane Aver Vanin, Eduardo Foschini Miranda, Paulo de Tarso Camillo de Carvalho, Simone Dal Corso, Jan Magnus Bjordal

Abstract: Recent studies have explored if phototherapy with low-level laser therapy (LLLT) or narrow-band light-emitting diode therapy (LEDT) can modulate activity-induced skeletal muscle fatigue or subsequently protect against muscle injury. We performed a systematic review with meta-analysis to investigate the effects of phototherapy applied before, during and after exercises. A literature search was performed in Pubmed/Medline database for randomized controlled trials (RCTs) published from 2000 through 2012. Trial quality was assessed with the ten-item PEDro scale. Main outcome measures were selected as: number of repetitions and time until exhaustion for muscle performance, and creatine kinase (CK) activity to evaluate risk for exercise-induced muscle damage. The literature search resulted in 16 RCTs, and three articles were excluded due to poor quality assessment scores. From 13 RCTs with acceptable methodological quality (≥6 of 10 items), 12 RCTs irradiated phototherapy before exercise, and 10 RCTs reported significant improvement for the main outcome measures related to performance. The time until exhaustion increased significantly compared to placebo by 4.12 s (95% CI 1.21-7.02, p < 0.005) and the number of repetitions increased by 5.47 (95% CI 2.35-8.59, p < 0.0006) after phototherapy. Heterogeneity in trial design and results precluded meta-analyses for biochemical markers, but a quantitative analysis showed positive results in 13 out of 16 comparisons. The most significant and consistent results were found with red or infrared wavelengths and phototherapy application before exercises, power outputs between 50 and 200 mW and doses of 5 and 6 J per point (spot).

Conclusion: We conclude that phototherapy (with lasers and LEDs) improves muscular performance and accelerate recovery mainly when applied before exercise.

Effects of photobiomodulation therapy in aerobic endurance training and detraining in humans

by Paulo Roberto Vicente de Paiva, PE, MSc, Heliodora Leão Casalechi, PT, PhD, Shaiane Silva Tomazoni, PT, PhD, Caroline dos Santos Monteiro Machado, PT, MSc,Eduardo Foschini Miranda, PT, PhD, Neide Firmo Ribeiro, PT, Amanda Lima Pereira, PT,a Amanda Sampaio da Costa, BSc, Luana Barbosa Dias, BSc, Bianca Cristina Gomes Souza, BSc, Matheus Marinho Aguiar Lino, BSc, Paulo de Tarso Camillo de Carvalho, PT, PhD, and Ernesto Cesar Pinto Leal-Junior, PT, PhD

Introduction: Over the last 10 years, it has been demonstrated that photobiomodulation therapy (PBMT), also known as phototherapy, using low-level laser therapy (LLLT) and/or light-emitting diode therapy (LEDT) has ergogenic effects, improving athletic performance and also accelerating post-exercise recovery. However, many aspects related to these effects and its clinical applicability remain unknown. Therefore, the aim of this project is to evaluate the ergogenic effects of PBMT in detraining after an aerobic endurance training protocol.

Discussion: Despite the increasing body of evidence for the use of PBMT as an ergogenic agent, several aspects remain unknown. The findings of this study will contribute to the advance of knowledge in this field regarding clinical applications.

Clinical and scientific recommendations for the use of photobiomodulation therapy in exercise performance enhancement and post-exercise recovery: current evidence and future directions

Ernesto Cesar Pinto Leal-Junior, Rodrigo Álvaro Brandão Lopes-Martins, Jan Magnus Bjordal


Background: There is about ten years since the first randomized controlled trial looking for the effects of photobiomodulation therapy using low-level laser therapy and/or light emitting diodes therapy in athletic performance enhancement was published. Since then, the knowledge in this field has increasing exponentially.

Objective: Given the fast advance in clinical interest, research and development in the use of photobiomodulation therapy for athletic performance enhancement and also to accelerate post-exercise recovery, as pioneers in this research field we felt the need to establish recommendations to ensure the correct use of the therapy, and also to guide the further studies in this area looking for the achievement of highest scientific evidence. It is important to highlight that the establishment of both clinical and scientific recommendations in this masterclass article were based on the most recent systematic reviews with meta-analysis and randomized controlled trials published in this field. It is important to stress that the recommendations of this masterclass article are based on most recent systematic reviews with meta-analysis and RCTs published in this research field. Future guidelines must follow the same direction and must be based only at the highest scientific evidence, avoiding overstatements and extrapolations based on animal experiments and case-studies.

man using FlexBeam for Neari-Infrared Light Therapy

Bone Healing

Near-infrared therapy promotes bone healing by stimulating osteoblast activity and enhancing the production of growth factors. As a result, these processes accelerate bone regeneration. It also improves blood circulation, ensuring that the healing bone receives sufficient oxygen and nutrients.

Effect of low level laser therapy on proliferation and differentiation of the cells contributing in bone regeneration

Reza Amid, Mahdi Kadkhodazadeh, Mitra Ghazizadeh Ahsaie, and Arian Hakakzadeh


Introduction: Low level laser therapy (LLLT) also known as photobiomodulation, is a treatment that uses low-level lasers or light-emitting diodes (LEDs) to change cellular function and is a clinically well accepted tool in regenerative medicine and dentistry. Considering the variety of laser, exposure, cells and study types, the exact effects of low level laser therapy seems to be unclear. The aim of this study was to review the data published in the field of the effects of low level laser therapy on proliferation and differentiation of the cells contributing in bone regeneration.

Methods: To access relevant articles, an electronic search in PubMed was conducted from 2001 to April 2014. English language published papers on low level laser therapy were found using the selected keywords .The full texts of potentially suitable articles were obtained for final assessment according to the exclusion and inclusion criteria.

Results: 240 articles were found from 2001 to April 2014. Following the initial screening of titles and abstracts as well as the final screening of full texts, 22 articles completely fulfilled the inclusion criteria of this study. Wavelength used in LLLT irradiation varied between 600 to 1000 nm with an energy density of 0.04–60J/cm2 . Although almost all studies agreed on getting positive effects from LLLT, some had opposing results.

Conclusion: Low level laser with low-energy density range appears to exert a biostimulatory effect on bone tissue, enhance osteoblastic proliferation and differentiation on cell lines used in in vitro studies. Despite the fact that many researches have been recently done on the effects of LLLT on different cell lines, without knowing the precise mechanism and effects, we are not able to offer a clinical treatment protocol. This paper is a beginning to help further progress and extend practical use of LLLT in future.

Effect of Low-Level Laser Therapy on Bone Regeneration During Osseointegration and Bone Graft

Randa Zein, Wayne Selting, and Stefano Benedicenti


Background: The effect of low-level laser therapy (LLLT) on bone regeneration during osseointegration and bone graft is very controversial. Despite many positive reports of in vitro and in vivo studies and more than 50 randomized clinical trials claiming a positive effect of photobiomodulation (PBM), many reports found no significant effect of lasers. 

Objective: The aim of this study was to evaluate studies correlating PBM and bone regeneration and to assesses parameters that produce positive results based on dose and output power used. 

Materials and methods: Four electronic databases were used: PubMed, Springer, Google Scholar, and Cochrane. 

Results: The research yielded 230 articles. The full texts of all articles were evaluated and scored using eligibility criteria adapted from Cericato et al. After evaluation, only 19 articles met the inclusion criteria. 

Conclusions: A positive effect of low-level laser energy on bone regeneration within a certain relationship between dose and output power was found. LLLT stimulates cellular metabolism, increasing protein synthesis and subsequent bone regeneration. A high dose combined with low power or a low dose combined with high power appears to produce a positive effect.

Photobiomodulation therapy (PBMT) in bone repair: A systematic review

by Jose Stalin Bayas Escudero, Maria Gabriela Benitez Perez, Marcelie Priscila de Oliveira Rosso, Daniela Vieira Buchaim, Karina Torres Pomini, Leila Maria Guissoni Campos, Mauro Audi, Rogério Leone Buchaim

Background: Photobiomodulation therapy (PBMT) using low-level laser influences the release of several growth factors involved in the formation of epithelial cells, fibroblasts, collagen and vascular proliferation, besides accelerating the synthesis of bone matrix due to the increased vascularization and lower inflammatory response, with significant increase of osteocytes in the irradiated bone. Considering its properties, beneficial effects and clinical relevance, the aim of this review was to analyze the scientific literature regarding the use of PBMT in the process of bone defect repair.

Conclusions: Many studies have shown that PBMT has positive photobiostimulatory effects on bone regeneration, accelerating its process regardless of parameters and the use of biomaterials. However, standardization of its use is still imperfect and should be better studied to allow correct application concerning the utilization protocols.


There are numerous case studies that demonstrate the efficiency of near-infrared therapy in cases of different tendinopaties. Here are some of those studies.

Analysis of pain relief and functional recovery in patients with rotator cuff tendinopathy through therapeutic ultrasound and photobiomodulation therapy: a comparative study

by João Pedro Scaldaferri Martins, Carlos José de Lima, Adriana Barrinha Fernandes, Leandro Procópio Alves, Osmar Pinto Neto, Antonio Balbin Villaverde

Abstract: This study aimed to compare shoulder tendinopathy treatment with therapeutic ultrasound combined with LED photobiomodulation therapy using LED-infrared (850 nm) or LED-red (640 nm). The study assessed 75 patients, aged 45 to 70 years, distributed into five experimental groups (15 patients each): therapeutic ultrasound (US), infrared light irradiation (IR), visible red light irradiation (VR), infrared light and ultrasound combined (IR-US), and red light in conjunction with ultrasound (VR-US). The ultrasound parameters are 1 MHz, 0.5 W/cm2 (SATA), and 100 Hz repetition rate, applied for 4 min each session. LED irradiation protocols were as follows: 3 points, 7.5 J per point, IR-LED 750 mW, 10 s, VR-LED 250 mW, 30 s. LED irradiation is followed by ultrasound in the combined therapies. The efficiency of the five therapies was evaluated assessing 12 parameters: quality of life (Health Assessment Questionnaire, HAQ), pain intensity (Visual Analog Scale, VAS), articular amplitude of shoulder movement (flexion, extension, abduction, adduction, medial rotation, lateral rotation), muscle strength (abduction, lateral rotation), and electromyography (lateral rotation, abduction). Treatments comprised 12 sessions for 4 weeks. Intra-group analysis showed that the five therapies significantly improved the recovery of all parameters after treatment. Regarding the comparison of irradiated therapies and ultrasound, statistical analysis showed that IR-US was a better treatment than US for all 12 parameters. IR treatment exceeded US on 9 items, whereas that VR and VR-US therapies exceeded US in 7 and 10 parameters, respectively (p < 0.05). Because of that, IR-US shows to be the best treatment for rotator cuff tendinopathy.

Conclusion: In conclusion, improvements in quality of life, pain intensity relief, shoulder amplitude motion, and muscle strength force obtained with ultrasound therapy are enhanced by adding infrared LED irradiation to ultrasound for patients suffering from rotator cuff tendinopathy. This study was registered with the Brazilian Registry of Clinical Trials (ReBEC) under Universal Trial Number (UTN) U1111-1219-3594 (2018/22/08).

Laser therapy in the treatment of achilles tendinopathy: a pilot study

by Steve Tumilty, Joanne Munn, J Haxby Abbott, Suzanne McDonough, Deirdre A Hurley, G David Baxter

Objective: To test the feasibility of a randomized controlled trial to assess the clinical effectiveness of low-level laser therapy (LLLT) when used in addition to eccentric exercise in the management of Achilles tendinopathy.

Background data: LLLT has emerged as a possible treatment modality for tendon injuries. Over the past 20 years only three human studies have investigated LLLT for Achilles tendinopathy.

Results: Within groups, there were significant improvements (p < 0.05) at 4 and 12 wk for all outcome measures, except eccentric strength for the placebo group at 4 wk (p = 0.11). Based on the results of the current study, recruitment of 20 subjects per group would be required to perform an adequately powered study based on minimally important clinical differences in VISA-A scale.

Conclusion: This study has demonstrated the feasibility of undertaking a randomized controlled trial of LLLT for Achilles tendinopathy. Conclusions regarding effectiveness cannot be made due to the low statistical power of this pilot study.

Comparison of Photobiomodulation and Anti-Inflammatory Drugs on Tissue Repair on Collagenase-Induced Achilles Tendon Inflammation in Rats

by Ingvill Fjell Naterstad, Rafael Paolo Rossi, Rodrigo Labat Marcos, Nivaldo Antonio Parizzoto, Lucio Frigo, Jón Joensen, Patrícia Sardinha Leonardo Lopes Martins, Jan Magnus Bjordal, Rodrigo Alvaro Brandão Lopes-Martins

Background: Tendinopathy is characterized by pain, edema, and structural changes in tendon tissue.

Objective: In this animal study we decided to compare the short- and medium-term effects of low-level laser therapy (LLLT), dexamethasone, and diclofenac on inflammation and tendon tissue repair in collagenase-induced tendinitis.

Results: Collagenase injection induced a severe inflammatory reaction with significant reduction in collagen content for 48 h, and disorientation of collagen fibers lasting between 14 and 21 days. Diclofenac and dexamethasone reduced inflammatory signs during the first 2 days, although there was prolongation of the inflammatory phase and slower normalization of tendon quality, particularly in the dexamethasone group. LLLT prevented hemorrhage, reduced inflammation severity, and preserved tendon morphology compared with the other groups.

Conclusions: LLLT showed a significant superiority over commonly used anti-inflammatory pharmaceutical agents in acute collagenase-induced tendinitis.

Photobiomodulation of pain in carpal tunnel syndrome: review of seven laser therapy studies

by Margaret A Naeser

Abstract: In this review, seven studies using photoradiation to treat carpal tunnel syndrome (CTS) are discussed: two controlled studies that observed real laser to have a better effect than sham laser, to treat CTS; three openprotocol studies that observed real laser to have a beneficial effect to treat CTS; and two studies that did not observe real laser to have a better effect than a control condition, to treat CTS. In the five studies that observed beneficial effect from real laser, higher laser dosages (9 Joules, 12-30 Joules, 32 J/cm(2), 225 J/cm(2)) were used at the primary treatment sites (median nerve at the wrist, or cervical neck area), than dosages in the two studies where real laser was not observed to have a better effect than a control condition (1.8 Joules or 6 J/cm(2)). The average success rate across the first five studies was 84% (SD, 8.9; total hands = 171). The average pain duration prior to successful photoradiation was 2 years.

Conclusion: Photoradiation is a promising new, conservative treatment for mild/moderate CTS cases (motor latency < 7 msec; needle EMG, normal). It is cost-effective compared to current treatments.


Joints are complex structures. Therefore, issues with them can be caused by different processes that involve bones, tendons, muscles, and more.

Effects of photobiomodulation therapy, pharmacological therapy, and physical exercise as single and/or combined treatment on the inflammatory response induced by experimental osteoarthritis

Tomazoni SS, Leal-Junior EC, Pallotta RC, Teixeira S, de Almeida P, Lopes-Martins RÁ.

Abstract: Osteoarthritis (OA) triggers increased levels of inflammatory markers, including prostaglandin (PG) E2 and proinflammatory cytokines. The elevation of cytokine levels is closely associated with increased articular tissue degeneration. Thus, the use of combination therapies may presumably be able to enhance the effects on the modulation of inflammatory markers. The present study aimed to evaluate and compare the effects of photobiomodulation therapy (PBMT), physical exercise, and topical nonsteroidal anti-inflammatory drug (NSAID) use on the inflammatory process after they were applied either alone or in different combinations. OA was induced by intra-articular papain injection in the knee of rats. After 21 days, the animals began treatment with a topical NSAID and/or with physical exercise and/or PBMT. Treatments were performed three times a week for eight consecutive weeks, totaling 24 therapy sessions. Analysis of real-time polymerase chain reaction (RT-PCR) gene expression; interleukin (IL)-1β, IL-6, and tumor necrosis factor alpha (TNF-α) protein expression; and PGE2 levels by enzyme-linked immunosorbent assay (ELISA) was conducted. Our results showed that PBMT alone and Exerc + PBMT significantly reduced IL-1β gene expression (p < 0.05) while no treatment changed both IL-6 and TNF-α gene expression. Treatment with NSAID alone, PBMT alone, Exerc + PBMT, and NSAID + PBMT reduced IL-1β protein expression (p < 0.05). All therapies significantly reduced IL-6 and TNF-α protein expression (p < 0.05) compared with the OA group. Similarly, all therapies, except Exerc, reduced the levels of PGE2 (p < 0.05) compared with the OA group.

Conclusion: The results from the present study indicate that treatment with PBMT is more effective in modulating the inflammatory process underlying OA when compared with the other therapies tested.

Photobiomodulation therapy (PBMT) on acute pain and inflammation in patients who underwent total hip arthroplasty-a randomized, triple-blind, placebo-controlled clinical trial

by Luciana Gonçalves Langella, Heliodora Leão Casalechi, Shaiane Silva Tomazoni, Douglas Scott Johnson, Regiane Albertini, Rodney Capp Pallotta, Rodrigo Labat Marcos, Paulo de Tarso Camillo de Carvalho, Ernesto Cesar Pinto Leal-Junior

Abstract: When conservative treatments fail, hip osteoarthritis (OA), a chronic degenerative disease characterized by cartilage wear, progressive joint deformity, and loss of function, can result in the need for a total hip arthroplasty (THA). Surgical procedures induced tissue trauma and incite an immune response. Photobiomodulation therapy (PBMt) using low-level laser therapy (LLLT) and/or light-emitting diode therapy (LEDT) has proven effective in tissue repair by modulating the inflammatory process and promoting pain relief. Therefore, the aim of this study was to analyze the immediate effect of PBMt on inflammation and pain of patients undergoing total hip arthroplasty. The study consisted of 18 post-surgical hip arthroplasty patients divided into two groups (n = 9 each) placebo and active PBMt who received one of the treatments in a period from 8 to 12 h following THA surgery. PBMt (active or placebo) was applied using a device consisting of nine diodes (one super-pulsed laser of 905 nm, four infrared LEDs of 875 nm, and four red LEDs 640 nm, 40.3 J per point) applied to 5 points along the incision. Visual analog scale (VAS) and blood samples for analysis of the levels of the cytokines TNF-α, IL-6, and IL-8 were recorded before and after PBMt application. The values for the visual analog scale as well as those in the analysis of TNF-α and IL-8 serum levels decreased in the active PBMt group compared to placebo-control group (p < 0.05). No decrease was observed for IL-6 levels.

Conclusion: We conclude that PBMt is effective in decreasing pain intensity and post-surgery inflammation in patients receiving total hip arthroplasty.

Scientific Studies on Mechanism of Action

Red and near-infrared therapy has been a subject of many clinical studies. While not a new form of therapy, it has been somewhat neglected by the scientific community. Luckily, this is changing and today, we have many significant papers exploring its mechanism of action.

Mechanisms and applications of the anti-inflammatory effects of photobiomodulation

by Michael R Hamblin

Abstract: Photobiomodulation (PBM) also known as low-level level laser therapy is the use of red and near-infrared light to stimulate healing, relieve pain, and reduce inflammation. The primary chromophores have been identified as cytochrome c oxidase in mitochondria, and calcium ion channels (possibly mediated by light absorption by opsins). Secondary effects of photon absorption include increases in ATP, a brief burst of reactive oxygen species, an increase in nitric oxide, and modulation of calcium levels. Tertiary effects include activation of a wide range of transcription factors leading to improved cell survival, increased proliferation and migration, and new protein synthesis. There is a pronounced biphasic dose response whereby low levels of light have stimulating effects, while high levels of light have inhibitory effects. It has been found that PBM can produce ROS in normal cells, but when used in oxidatively stressed cells or in animal models of disease, ROS levels are lowered.

Key points:

  • PBM is able to up-regulate anti-oxidant defenses and reduce oxidative stress. It was shown that PBM can activate NF-kB in normal quiescent cells, however in activated inflammatory cells, inflammatory markers were decreased.
  • One of the most reproducible effects of PBM is an overall reduction in inflammation, which is particularly important for disorders of the joints, traumatic injuries, lung disorders, and in the brain.
  • PBM has been shown to reduce markers of M1 phenotype in activated macrophages. Many reports have shown reductions in reactive nitrogen species and prostaglandins in various animal models.
  • PBM can reduce inflammation in the brain, abdominal fat, wounds, lungs, spinal cord.

Melatonin as a principal component of red light therapy

by Ronnie L Yeager, Deanna A Oleske, Ruth A Sanders, John B Watkins 3rd, Janis T Eells, Diane S Henshel

Abstract: Melatonin is well recognized for its role as a potent antioxidant and is directly implicated in the free radical theory of aging [1] [Reiter RJ, Pablos MI, Agapito TT, Guerrero JM. Melatonin in the context of the free radical theory of aging. Ann N Y Acad Sci 1996;786:362-78]. Moreover, melatonin has been shown to retard age-related increases in lipid peroxidation and oxidative damage [2] [Okatani Y, Wakatsuki A, Reiter RJ. Melatonin protects hepatic mitochondrial respiratory chain activity in senescence-accelerated mice. J Pineal Res 2002;32:143-8] and to act directly upon the immune system [3] [Poon AM, Liu ZM, Pang CS, Brown GM, Pang SF. Evidence for a direct action of melatonin on the immune system. Biol Signals 1994;3:107-17]. This report focuses on characterizing documented functions of melatonin in the context of red light therapy and proposes that melatonin is a potential mediator of red light’s therapeutic effects, a hypothesis that is as yet untested.

Key points:

  • Red light therapy (670 nm, 4J/cm(2)) has been shown to restore glutathione redox balance upon toxicological insult and enhance both cytochrome c oxidase and energy production, all of which may be affected by melatonin.
  • The red light treatment has also been successfully implemented in the clinical setting for its effectiveness in reducing both the number of incidences and severity of oral mucositis resulting in part from the chemotherapy and/or radiation administered prior to bone marrow transplants.
  • Moreover, red light therapy improves wound healing and is being further tested for its ability to ameliorate toxicant-induced retinal and visual cortical neuron damage. Researchers in the growing field of light therapy may be in a position to draw from and collaborate with melatonin researchers to better characterize this alternative treatment.

The nuts and bolts of low-level laser (light) therapy

Chung H, Dai T, Sharma SK, Huang YY, Carroll JD, Hamblin MR

Abstract: Soon after the discovery of lasers in the 1960s it was realized that laser therapy had the potential to improve wound healing and reduce pain, inflammation and swelling. In recent years the field sometimes known as photobiomodulation has broadened to include light-emitting diodes and other light sources, and the range of wavelengths used now includes many in the red and near infrared. The term “low level laser therapy” or LLLT has become widely recognized and implies the existence of the biphasic dose response or the Arndt-Schulz curve. This review will cover the mechanisms of action of LLLT at a cellular and at a tissular level and will summarize the various light sources and principles of dosimetry that are employed in clinical practice.

Key points: The range of diseases, injuries, and conditions that can be benefited by LLLT will be summarized with an emphasis on those that have reported randomized controlled clinical trials. Serious life-threatening diseases such as stroke, heart attack, spinal cord injury, and traumatic brain injury may soon be amenable to LLLT therapy.

Is light-emitting diode phototherapy (LED-LLLT) really effective?

by Won-Serk Kim and R Glen Calderhead

Background: Low level light therapy (LLLT) has attracted attention in many clinical fields with a new generation of light-emitting diodes (LEDs) which can irradiate large targets. To pain control, the first main application of LLLT, have been added LED-LLLT in the accelerated healing of wounds, both traumatic and iatrogenic, inflammatory acne and the patient-driven application of skin rejuvenation.

Rationale and Applications: The rationale behind LED-LLLT is underpinned by the reported efficacy of LED-LLLT at a cellular and subcellular level, particularly for the 633 nm and 830 nm wavelengths, and evidence for this is presented. Improved blood flow and neovascularization are associated with 830 nm. A large variety of cytokines, chemokines and macromolecules can be induced by LED phototherapy. Among the clinical applications, non-healing wounds can be healed through restoring the collagenesis/collagenase imbalance in such examples, and ‘normal’ wounds heal faster and better. Pain, including postoperative pain, postoperative edema and many types of inflammation can be significantly reduced.

Experimental and clinical evidence: Some personal examples of evidence are offered by the first author, including controlled animal models demonstrating the systemic effect of 830 nm LED-LLLT on wound healing and on induced inflammation. Human patients are presented to illustrate the efficacy of LED phototherapy on treatment-resistant inflammatory disorders.

Conclusions: Provided an LED phototherapy system has the correct wavelength for the target cells, delivers an appropriate power density and an adequate energy density, then it will be at least partly, if not significantly, effective. The use of LED-LLLT as an adjunct to conventional surgical or nonsurgical indications is an even more exciting prospect. LED-LLLT is here to stay.

Other Scientific Studies

These clinical studies demonstrate the great power of photobiomodulation. Recharge Health medical team has been able to create small-scale case studies using FlexBeam to demonstrate its effectiveness and therapeutic properties with great success.

Near infrared/ red light therapy a potential countermeasure for mitochondrial dysfunction in spaceflight associated neuro-ocular syndrome (SANS)

Ethan Waisberg, Joshua Ong, Mouayad Masalkhi & Andrew G. Lee

Introduction:Spaceflight-associated neuro-ocular syndrome (SANS) is a syndrome know to affect a significant proportion of astronauts during long-duration spaceflight (LDSF). SANS is characterized by optic disc edema [1], hyperopic shifts [2], chorioretinal folds [3] and globe flattening [4]. While the precise etiology of SANS remains incompletely understood, it is hypothesized to be as a result of the unique conditions encountered in the microgravity environment characteristic of LDSF, and heightened radiation exposure [5]. So far, SANS has been associated with alterations in fluid distribution and ocular structural adaptations induced by microgravity conditions [5].

Key points:

  • Red/Near Infrared (NIR) Light Therapy may serve as a non-invasive and side-effect-free countermeasure to improve mitochondrial function during LDSF.
  • NIR/red light therapy is a form of phototherapy that utilizes specific wavelengths of light to promote healing and reduce inflammation [15, 16].
  • NIR/red light therapy is believed to enhance mitochondrial function via the absorption of photons by mitochondrial chromophores, such as cytochrome c oxidase, contributing to improved cellular respiration and ATP production, and reducing ROS generation [17].
  • NIR/red light also has known anti-inflammatory properties, which could mitigate inflammation associated with SANS and its impact on ocular tissues [17].
  • Furthermore, secondary effects can also occur hours following NIR/red light exposure including the dissociation of nitric oxide from its binding site, modification of the ATP pool and an increased mitochondrial intermembrane potential (Fig. 1) [18].
  • Alterations in ATP levels can affect cyclic adenosine monophosphate levels, intracellular calcium levels and cellular metabolism.

PBMT and topical diclofenac as single and combined treatment on skeletal muscle injury in diabetic rats: effects on biochemical and functional aspects

by Ligiane Souza Dos Santos, Joyce Camilla Saltorato, Marina Gaiato Monte, Rodrigo Labat Marcos, Rodrigo Álvaro Brandão Lopes-Martins, Shaiane Silva Tomazoni, Ernesto Cesar Pinto Leal-Junior, Rodrigo Leal de Paiva Carvalho

Abstract: Physical exercise generates several benefits in a short time in patients with diabetes mellitus. However, it can increase the chances of muscle damage, a serious problem for diabetic patients. Nonsteroidal anti-inflammatory drugs (NSAIDs) are widely used to treat these injuries, despite the serious adverse effects. In this way, photobiomodulation therapy (PBMT) with low-level laser therapy (LLLT) and/or light emitting diode therapy (LEDT) can be used as an alternative in this case. However, its efficacy in tissue repair of trauma injuries in diabetes mellitus until now is unknown, as well as the combination between PBMT and NSAIDs. The objective of the present study was to evaluate the effects of NSAIDs and PBMT applied alone or combined on functional and biochemical aspects, in an experimental model of muscle injury through controlled trauma in diabetic rats. Muscle injury was induced by means of a single trauma to the animals’ anterior tibialis muscle. After 1 h, the rats were treated with PBMT (830 nm; continuous mode, with a power output of 100 mW; 3.57 W/cm2; 3 J; 107.1 J/cm2, 30 s), diclofenac sodium for topical use (1 g), or combination of them. Our results demonstrated that PBMT + diclofenac, and PBMT alone reduced the gene expression of cyclooxygenase-2 (COX-2) at all assessed times as compared to the injury and diclofenac groups (p < 0.05 and p < 0.01 respectively). The diclofenac alone showed reduced levels of COX-2 only in relation to the injury group (p < 0.05). Prostaglandin E2 levels in blood plasma demonstrated similar results to COX2. In addition, we observed that PBMT + diclofenac and PBMT alone showed significant improvement compared with injury and diclofenac groups in functional analysis at all time points.

Conclusion: The results indicate that PBMT alone or in combination with diclofenac reduces levels of inflammatory markers and improves gait of diabetic rats in the acute phase of muscle injury.

Near-Infrared Light Therapy to Attenuate Strength Loss After Strenuous Resistance Exercise

by Kelly A. Larkin-Kaiser, PhD, CAT(C), Evangelos Christou, PhD, Mark Tillman, PhD, Steven George, PhD, PT, and Paul A. Borsa, PhD, ATC, FACSM

Context: Near-infrared (NIR) light therapy is purported to act as an ergogenic aid by enhancing the contractile function of skeletal muscle. Improving muscle function is a new avenue for research in the area of laser therapy; however, very few researchers have examined the ergogenic effects of NIR light therapy and the influence it may have on the recovery process during rehabilitation.

Objective: To evaluate the ergogenic effect of NIR light therapy on skeletal muscle function.

Conclusions: Applied to skeletal muscle before resistance exercise, NIR light therapy effectively attenuated strength loss. Therefore, NIR light therapy may be a beneficial, noninvasive modality for improving muscle function during rehabilitation after musculoskeletal injury. However, future studies using higher treatment doses are warranted.

FlexBeam Case Studies

These clinical studies demonstrate the great power of photobiomodulation. Recharge Health medical team has been able to create small-scale case studies using FlexBeam to demonstrate its effectiveness and therapeutic properties with great success.