Evidence map›Paper›PMID 28070154›Full record

ArticleIEEE journal of selected topics in quantum electronics : a publication of the IEEE Lasers and Electro-optics Society

Proposed Mechanisms of Photobiomodulation or Low-Level Light Therapy.

Lucas Freitas de Freitas, Michael R Hamblin

8 registry-linked trialsOpen access · greenAbstract read
PubMed Full text at PMC Publisher
In one paragraph

Article in IEEE journal of selected topics in quantum electronics : a publication of the IEEE Lasers and Electro-optics Society. The graph could read no effect estimate from its abstract, so it casts no vote on the map. It is linked to 8 registered trials, which are not on this map. Cited by 688 papers, 13 of them syntheses that pooled it.

0numbers the graph read from it
0cells of the map it votes in
688citing papers in PubMed, 13 pooled it
61.2field-weighted citation impact, top 1% of its field
1 · What the graph read from it

What it found

Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.

The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

The trial behind it

Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.

NCT04598854 nacompletednot on this map

The Investigation of Therapeutic Effect and Molecular Mechanism After Intravascular Laser Irradiation of Blood for Osteoarthritis of Knee

TypeinterventionalSponsorTri-Service General Hospital (TSGH)Ran2020 to 2023Enrolled17ConditionsOsteoarthritis, KneeArmsIntravascular laser irradiation of blood, Intravascular laser irradiation of blood (Sham)
NCT04751942 nacompletednot on this map

Post-operative Comparison Between Standard Gradient Compression Dressing vs. Non-Compressive Bioactive Garment on Pain, Swelling and Range of Motion Following Total Knee Arthroplasty

TypeinterventionalSponsorUniversity Hospitals Cleveland Medical CenterRan2023 to 2025Enrolled23ConditionsOsteoarthritis Knees BothArmsNon-compressive Bioactive Garment, thrombo-embolic deterrent
NCT04808492 nawithdrawnnot on this map

The Effects of CureWave Laser on Paraspinal Muscle Oxygenation, Pressure Pain Thresholds, Muscle Edema, Muscle Quality, and Perceived Outcomes in Patients With Chronic Low Back Pain.

TypeinterventionalSponsorUniversity of Central FloridaRan2022 to 2022Enrolled0ConditionsLow Back PainArmsCureWave High Intensity Laser, Placebo
NCT05689788 narecruitingnot on this map

Effect of High-intensity Laser Therapy in Patients With Chronic Nonspecific Neck Pain. Randomized Clinical Trial

TypeinterventionalSponsorQuiropraxia y EquilibrioRan2024 to 2025Enrolled72ConditionsNon-specific Chronic Neck PainArmsHigh-intensity laser therapy, Stretching exercise, Sham High-intensity laser therapy
NCT06352372 phase2completednot on this map

Safety and Efficacy of Transcranial Photobiomodulation (tPBM) for Individuals With Autism Spectrum Disorder and Epileptiform Activity

TypeinterventionalSponsorRichard FryeRan2024 to 2026Enrolled6ConditionsAutism Spectrum Disorder, EEG With Periodic Abnormalities, Epilepsy, Neurodevelopmental DisordersArmsnoninvasively delivered near infra-red (NIR) light - transcranial Photobiomodulation (tPBM)
NCT07445945 nanot yet recruitingnot on this map

Physiological Effect of Non-invasive Photobiomodulation on Cognition and Mood in Older Adults With Subjective Cognitive Impairment

TypeinterventionalSponsorBaycrestRan2026 to 2028Enrolled80ConditionsSubjective Cognitive Decline (SCD), Subjective Cognitive ImpairmentArmsPhotobiomodulation, Sham (No Treatment)
NCT07453927 narecruitingnot on this map

Blue Light in the Treatment of Donor Site in Burn Patient: a Controlled Clinical Trial

TypeinterventionalSponsorAUSL Romagna RiminiRan2025 to 2026Enrolled25ConditionsDonor Site Complication, Burn, Photobiomodulation Therapy, Blue LightArmsPhotobiomodulation with blue light
NCT07651787 narecruitingnot on this map

Neurovascular and Mitochondrial Mechanisms of Transcranial Photobiomodulation in Vascular Mild Cognitive Impairment

TypeinterventionalSponsorUniversity of OklahomaRan2025 to 2026Enrolled40ConditionsMild Cognitive Impairment (MCI), Amyloid PathologyArmsActive Vielight Neuro RX-Duo device -Active transcranial photobiomodulation, Sham Vielight Neuro RX-Duo device -Sham transcranial photobiomodulation
3 · Its place in the literature

Who cites it

688 citing papers in PubMed, 13 syntheses or guidelines pooled it, 1,507 citations in OpenAlex.

  1. Pooled it
  2. Do Laser and Light Activation Improve In-Office Dental Bleaching Outcomes? An Umbrella Review of Efficacy, Tooth Sensitivity, and Biological Safety.Journal of esthetic and restorative dentistry : official publication of the American Academy of Esthetic Dentistry ... [et al.] · 2026
    Pooled it
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  5. Analgesic Efficacy of Low-Level Laser Therapy for Postoperative Endodontic Pain: A Systematic Review and Meta-Analysis.Australian endodontic journal : the journal of the Australian Society of Endodontology Inc · 2026
    Pooled it
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  14. Trial
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  20. Effects from a single application of photobiomodulation on pain intensity from perineal trauma related to childbirth: A randomized controlled trial.International journal of gynaecology and obstetrics: the official organ of the International Federation of Gynaecology and Obstetrics · 2026
    Trial

628 more citing papers are in PubMed but not listed here.

4 · The record

Corrections and comments

PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.

5 · Who and what money

Authors and funding

2 authors at 2 institutions in 2 countries.

Lucas Freitas de FreitasPrograma de Pós-Graduação Interunidades Bioengenharia, University of São Paulo, São Carlos - SP, Brazil; Wellman Center for Photomedicine, Harvard Medical School, Boston, MA 02114, USA.
Michael R HamblinWellman Center for Photomedicine, Harvard Medical School, Boston, MA 02114, USA; Department of Dermatology, Harvard Medical School, Boston, MA 02115, USA; Harvard-MIT Division of Health Sciences and Technology, Cambridge, MA 02139, USA.
Harvard–MIT Division of Health Sciences and Technology · USUniversidade de São Paulo · BR

Funding

Photodynamic Therapy of Localized InfectionsR01AI050875 · NIAID · MASSACHUSETTS GENERAL HOSPITAL · PI HAMBLIN, MICHAEL R · 2003 to 2017
$4.8M
Synergistic Photodynamic Therapy for Catherer-Associated Urinary Tract InfectionsR21AI121700 · NIAID · MASSACHUSETTS GENERAL HOSPITAL · PI HAMBLIN, MICHAEL R · 2016 to 2017
$462k
NIAID NIH HHS R01 AI050875NIAID NIH HHS R21 AI121700
6 · The paper itself

Abstract

Photobiomodulation (PBM) also known as low-level laser (or light) therapy (LLLT), has been known for almost 50 years but still has not gained widespread acceptance, largely due to uncertainty about the molecular, cellular, and tissular mechanisms of action. However, in recent years, much knowledge has been gained in this area, which will be summarized in this review. One of the most important chromophores is cytochrome c oxidase (unit IV in the mitochondrial respiratory chain), which contains both heme and copper centers and absorbs light into the near-infra-red region. The leading hypothesis is that the photons dissociate inhibitory nitric oxide from the enzyme, leading to an increase in electron transport, mitochondrial membrane potential and ATP production. Another hypothesis concerns light-sensitive ion channels that can be activated allowing calcium to enter the cell. After the initial photon absorption events, numerous signaling pathways are activated via reactive oxygen species, cyclic AMP, NO and Ca2+, leading to activation of transcription factors. These transcription factors can lead to increased expression of genes related to protein synthesis, cell migration and proliferation, anti-inflammatory signaling, anti-apoptotic proteins, antioxidant enzymes. Stem cells and progenitor cells appear to be particularly susceptible to LLLT.

Indexed as

Cytochrome c oxidaseLight sensitive ion channelsLow Level Light TherapyMechanismMitochondriaPhotobiomodulation

Identifiers

PMID28070154
PMCPMC5215870
OpenAlexW2414212658

What OpenQuestion holds

Textmetadata
LicenceTDM
Read underepoch 390

Registered trials

and 2 more above

Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.