Published English-language literature

PBM research statistics

Publications10,028English-language publications in the database (2026)
Indication entries293entries across 24 medical specialties
Countries65countries represented in the published literature

Source: PBM Database statistics, WALT 2026 presentation and the updated PBM indications workbook. The workbook contains 293 indication rows; overlapping labels are grouped in the directory.

Publication growth and research locations

Photobiomodulation research over time

Each bar shows the running publication-record total through that year. Its segments show the countries recorded in the database.

Cumulative PBM publication records by countryStacked bars show cumulative PBM Database records from 1980 through six milestone years. Totals are 623 in 2000, 963 in 2005, 1,722 in 2010, 3,112 in 2015, 5,577 in 2020 and 9,193 in 2025. Sunlight records are excluded.02,5005,0007,50010,000Brazil: 5 records through 2000United States: 80 records through 2000China: 10 records through 2000Korea: 8 records through 2000Italy: 34 records through 2000Turkey: 2 records through 2000Japan: 115 records through 2000India: 4 records through 2000Other / unreported: 365 records through 2000623Brazil: 55 records through 2005United States: 128 records through 2005China: 20 records through 2005Iran: 5 records through 2005Korea: 10 records through 2005Italy: 48 records through 2005Turkey: 19 records through 2005Japan: 135 records through 2005India: 10 records through 2005Other / unreported: 533 records through 2005963Brazil: 276 records through 2010United States: 221 records through 2010China: 53 records through 2010Iran: 42 records through 2010Korea: 25 records through 2010Italy: 67 records through 2010Turkey: 55 records through 2010Japan: 168 records through 2010India: 15 records through 2010Other / unreported: 800 records through 20101,722Brazil: 718 records through 2015United States: 384 records through 2015China: 137 records through 2015Iran: 128 records through 2015Korea: 94 records through 2015Italy: 111 records through 2015Turkey: 103 records through 2015Japan: 208 records through 2015India: 43 records through 2015Other / unreported: 1,186 records through 20153,112Brazil: 1,449 records through 2020United States: 625 records through 2020China: 264 records through 2020Iran: 337 records through 2020Korea: 191 records through 2020Italy: 220 records through 2020Turkey: 209 records through 2020Japan: 244 records through 2020India: 102 records through 2020Other / unreported: 1,936 records through 20205,577Brazil: 2,224 records through 2025United States: 935 records through 2025China: 758 records through 2025Iran: 662 records through 2025Korea: 346 records through 2025Italy: 342 records through 2025Turkey: 315 records through 2025Japan: 293 records through 2025India: 253 records through 2025Other / unreported: 3,065 records through 20259,193200020052010201520202025
  • Brazil2,224 records
  • United States935 records
  • China758 records
  • Iran662 records
  • Korea346 records
  • Italy342 records
  • Turkey315 records
  • Japan293 records
  • India253 records
  • Other / unreported3,065 records
Cumulative records from 1980 through each milestone year.Sunlight records and partial 2026 data omitted.

PBM Database snapshot: 25 September 2026. Eleven records dated before 1980 and three without a usable year are outside this timeline. Country groups use the first country listed in the database; “Other / unreported” combines remaining entries and records without a country.

Countries represented

Publication counts by country

Counts for the 30 most represented single-country groups are shown below. The remainder is split into other countries, multinational entries and records with an unverified country.

Brazil
2,356
United States
991
China
872
Iran
693
Korea
368
Italy
360
Turkey
336
Japan
302
India
285
Russia
205
Egypt
200
Taiwan
195
UK
195
Australia
187
Israel
162
Germany
149
Spain
148
South Africa
125
Poland
120
Canada
116
France
115
Saudi Arabia
92
Austria
65
Belgium
51
Norway
47
Sweden
42
Portugal
39
Thailand
39
Syria
39
Iraq
33
Other countries
604
Multinational
203
Country unverified
107

The 30 named groups total 8,927 records; 604 are from other countries, 203 are multinational and 107 have an unverified country (9,841 total).

PBM Database checked 16 October 2026 · Sunlight excluded. Counts reflect database records, not deduplicated publications. Multinational entries name multiple countries or are marked international. Country unverified includes blank, placeholder and unresolved entries; limited full-text access may prevent confirmation.

Study models

Publications by study model

The database groups publications as human research, animal experiments or in-vitro research.

Human studies

3,326 publications
Human

clinical and human research

Randomized, negative-control1,790
Randomized, positive-control140
Placebo-controlled1,572

Animal experiments

2,546 publications
Animal

preclinical research

Rat1,576Mouse631Rabbit157Dog72Pig27Hamster20Chicken / chick embryo19Guinea pig17Horse14Nonhuman primate10Fruit fly10Cattle10Sheep9Zebrafish5Toad5Cat5Tree shrew4Bumblebee3Planarian3Frog / tadpole2Daphnia2Earthworm2Nematode2Parakeet1Ray1Gerbil1Honeybee1Medaka1Catfish1

In-vitro studies

1,733 publications
In vitro

cellular and laboratory research

Cell types & cell lines
  • Dermal fibroblasts
  • Keratinocytes
  • Osteoblasts
  • Adipose-derived stem cells
  • Neurons
  • Astrocytes
  • Gingival fibroblasts
  • Dental pulp stem cells
  • Myoblasts
  • Endothelial cells
  • Macrophages
  • Chondrocytes
  • Mesenchymal stem cells
  • Schwann cells
  • Microglia
  • Cardiomyocytes
  • Osteoclasts
  • Monocytes
  • Periodontal ligament stem cells
  • Adipocytes
  • Myotubes
  • Neural stem cells
  • Smooth muscle cells
  • Lymphocytes
  • Odontoblasts
  • Hepatocytes
  • Melanocytes
  • Umbilical cord MSCs
  • Dermal papilla cells
  • Neutrophils
  • Retinal pigment epithelial cells
  • Erythrocytes
  • Spermatozoa
  • HaCaT
  • SH-SY5Y
  • PC12
  • C2C12
  • RAW 264.7
  • MC3T3-E1
  • MCF-7
  • HeLa

Selected examples from PBM Database in-vitro records.

Review literature

Reviews in the database

Meta-analyses are included within the systematic-review count.

Narrative reviews1,080
Systematic reviews700
Including meta-analysis360

Cumulative overview

Publications over time

Each year shows the cumulative number of dated records through that year.

Cumulative publications by study model and designHeatmap of cumulative publication counts from the PBM Database at ten year checkpoints. Human randomized and sham-controlled rows are nested subsets. Systematic reviews include meta-analyses, which are also shown as a subset.TOTAL1970198019902000200520102015202020252026Human02502063165679881,8003,1033,331↳ Human & randomized0019881452875401,0641,8071,938↳ Human, randomized & sham-controlled0013721141973266329691,033Rat studies0025871613466871,0961,5041,552Mouse studies126233567165326573612Rabbit studies00419295895126146150Other animal studies001341476490159234247In vitro studies12331241973375659501,4611,541Ex vivo studies0061930395477101103In vitro / ex vivo111111181819Narrative reviews132458821392364959111,007Systematic reviews0004142976242625692↳ Meta-analyses (subset)000261539105308358Other review types000000111524Protocols0000001162123137Editorials & commentary00619233072119171177Other publications121132385581124213244

Cell shading shows each row’s share of its final total. Human design rows are nested subsets. Systematic reviews include meta-analyses, shown again as a subset. Sham-controlled includes records labelled “sham-controlled”, “double-blind” or “triple-blind”.

PBM Database snapshot, 4 October 2026 · 9,836 dated records · Sunlight excluded · 2026 incomplete

Research publication venues

PBM research appears in high-impact journals

187journals listed at IF ≥ 3.0

Examples across different kinds of research

PBM Database journal counts

Which journals appear most often in the database?

This frequency ranking reflects journal names in database records.

  1. Lasers in Medical Science1,424
  2. Photobiomodulation, Photomedicine, and Laser Surgery900
  3. Lasers in Surgery and Medicine329
  4. Journal of Photochemistry and Photobiology B311
  5. Journal of Lasers in Medical Sciences252
  6. Laser Therapy208
  7. Journal of Biophotonics173
  8. Photochemistry and Photobiology161
  9. Scientific Reports129
  10. Photodiagnosis and Photodynamic Therapy117

Counts are journal-name entries in 10,025 PBM Database records with a journal listed (data checked 26 September 2026). “Photomed Laser Surg” and “Photobiomodul Photomed Laser Surg” are combined under the journal’s current title. Counts describe database records, not journal quality or evidence strength.

PBM Database details

Research models, treatment parameters and topic growth

Human study sample sizes

Numerical sample sizes appear in 2,931 of 3,341 human-research records. Median recorded sample size: 36.

Under 20624 21.3%
20–29469 16.0%
30–39446 15.2%
40–49391 13.3%
50–99741 25.3%
100–199183 6.2%
200 or more77 2.6%

Human study treatment durations

A classifiable treatment duration is recorded in 1,978 of 3,342 human-research records (59.2%). Bars show the distribution among those 1,978 records.

1 day499 25.2%
2–3 days71 3.6%
4–6 days87 4.4%
1 week81 4.1%
8–11 days59 3.0%
2 weeks173 8.7%
3 weeks183 9.3%
1 month304 15.4%
5 weeks59 3.0%
6 weeks102 5.2%
7 weeks19 1.0%
2 months124 6.3%
10 weeks35 1.8%
3 months97 4.9%
4 months20 1.0%
5 months6 0.3%
6 months29 1.5%
7–8 months4 0.2%
9–11 months3 0.2%
12–17 months11 0.6%
18–23 months1 0.1%
≥24 months11 0.6%

Source: PBM Database, checked 17 October 2026; publication records, not deduplicated trials. Durations are approximate: 4 weeks ≈ 1 month, 8 weeks ≈ 2 months and 12 weeks ≈ 3 months. A single session or a course lasting up to 24 hours counts as 1 day. We use explicit course lengths from “N sessions” or a treatment duration labelled in Study type. The ≥24-month group counts source-verified publications: a qualifying exposure in at least one treatment arm or case is counted once per publication; some records have mixed durations and cohort publications may overlap. Follow-up and data-collection periods, frequency alone, uncertain courses and unverified ranges are not treated as PBM exposure.

LIGHT PARAMETERS

Wavelengths recorded

405–590 nm

Violet to amber

302 records

  • 405 nm47
  • 450 nm42
  • 470 nm47
  • 532 nm61
  • 590 nm59

625–640 nm

Red

1,181 records

  • 625 nm38
  • 630 nm259
  • 633 nm544
  • 635 nm220
  • 640 nm80

650–690 nm

Red

1,940 records

  • 650 nm278
  • 655 nm53
  • 660 nm1,199
  • 670 nm295
  • 685 nm73

780–810 nm

Near-infrared

1,753 records

  • 780 nm295
  • 800 nm31
  • 808 nm795
  • 810 nm619

820–850 nm

Near-infrared

1,062 records

  • 820 nm64
  • 830 nm657
  • 850 nm326

870–910 nm

Near-infrared

642 records

  • 875 nm40
  • 880 nm66
  • 890 nm110
  • 904 nm296
  • 905 nm130

940–980 nm

Near-infrared

542 records

  • 940 nm208
  • 950 nm40
  • 970 nm47
  • 980 nm252

1064–1072 nm

Near-infrared

256 records

  • 1064 nm240

Database snapshot: 25 September 2026.

625–640 nm

Red

1,181 records

  • 625 nm38
  • 630 nm259
  • 632 nm25
  • 633 nm544
  • 635 nm220
  • 637 nm22
  • 640 nm80

650–690 nm

Red

1,940 records

  • 650 nm278
  • 655 nm53
  • 658 nm35
  • 660 nm1,199
  • 670 nm295
  • 680 nm22
  • 685 nm73
  • 690 nm9

780–810 nm

Near-infrared

1,753 records

  • 780 nm295
  • 790 nm20
  • 800 nm31
  • 808 nm795
  • 810 nm619

820–850 nm

Near-infrared

1,062 records

  • 820 nm64
  • 825 nm24
  • 830 nm657
  • 850 nm326

870–910 nm

Near-infrared

642 records

  • 870 nm21
  • 875 nm40
  • 880 nm66
  • 890 nm110
  • 904 nm296
  • 905 nm130
  • 910 nm23

940–980 nm

Near-infrared

542 records

  • 940 nm208
  • 950 nm40
  • 970 nm47
  • 980 nm252

1064–1072 nm

Near-infrared

256 records

  • 1064 nm240
  • 1070 nm7
  • 1072 nm9

Database snapshot: 25 September 2026; Sunlight records excluded. Group totals count each record once across the wavelengths shown in that group. Individual wavelength counts may overlap. Bars share one scale. All exact values appearing in at least 20 records between 400 and 1100 nm are included above, with 690, 1070 and 1072 nm also shown.

TREATMENT PARAMETERS

Recorded energy density

Below 11 to <55 to <1010 to <2020 to <5050 or more

Human

n = 1,096 records
Median8
Mean75.3

Rat

n = 676 records
Median8
Mean71.1

Mouse

n = 207 records
Median5
Mean20.0

Rabbit

n = 54 records
Median6
Mean46.3

In vitro

n = 326 records
Median4.3
Mean17.3

Database snapshot: 25 September 2026.

Citation ranking · broad literature search

20 highly cited PBM papers

  1. 01

    Proposed Mechanisms of Photobiomodulation or Low-Level Light Therapy

    Lucas Freitas de Freitas, Michael R. Hamblin

    1,6402016
  2. 02

    Primary and secondary mechanisms of action of visible to near-IR radiation on cells

    Tiina I. Karu

    1,3851999
  3. 03

    Mechanisms and applications of the anti-inflammatory effects of photobiomodulation

    Michael R. Hamblin

    1,2682017
  4. 04

    Mechanisms and Mitochondrial Redox Signaling in Photobiomodulation

    Michael R. Hamblin

    8262017
  5. 05

    Photobiomodulation: Underlying Mechanism and Clinical Applications

    Claudia Dompé, Lisa Moncrieff, Jacek Matys, et al.

    7942020
  6. 06

    Photobiology of low-power laser effects

    Tiina Karu

    7491989
  7. 07

    Low-Level Light/Laser Therapy Versus Photobiomodulation Therapy

    Juanita J. Anders, Raymond J. Lanzafame, Praveen R. Arany

    6622015
  8. 08

    Shining light on the head: Photobiomodulation for brain disorders

    Michael R. Hamblin

    6412016
  9. 09

    Photobiomodulation directly benefits primary neurons functionally inactivated by toxins: role of cytochrome c oxidase

    Margaret T. T. Wong-Riley, Huan Ling Liang, Janis T. Eells, et al.

    6332005
  10. 10

    Exact Action Spectra for Cellular Responses Relevant to Phototherapy

    Tiina I. Karu, Sergei F. Kolyakov

    6162005
  1. 11

    Efficacy of low-level laser therapy in the management of neck pain: a systematic review and meta-analysis of randomised placebo or active-treatment controlled trials

    Roberta T. Chow, Mark I. Johnson, Rodrigo Álvaro Brandão Lopes-Martins, et al.

    6152009
  2. 12

    A systematic review of low level laser therapy with location-specific doses for pain from chronic joint disorders

    Jan Magnus Bjordal, Christian Couppé, Roberta T. Chow, et al.

    5862003
  3. 13

    Low-level laser therapy in acute pain: a systematic review of possible mechanisms of action and clinical effects in randomized placebo-controlled trials

    Jan Magnus Bjordal, Mark I. Johnson, Vegard Vereide Iversen, et al.

    5862006
  4. 14

    Low-level laser therapy: a useful technique for enhancing the proliferation of various cultured cells

    Khalid M. AlGhamdi, Ashok Kumar, Noura A. Moussa

    5792011
  5. 15

    Mitochondrial Signaling in Mammalian Cells Activated by Red and Near-IR Radiation

    Tiina I. Karu

    5572008
  6. 16

    Brain Photobiomodulation Therapy: a Narrative Review

    Farzad Salehpour, Javad Mahmoudi, Farzin Kamari, et al.

    5352018
  7. 17

    Low-level laser therapy activates NF-kB via generation of reactive oxygen species in mouse embryonic fibroblasts

    Aaron C.-H. Chen, Praveen R. Arany, Ying-Ying Huang, et al.

    5252011
  8. 18

    Molecular mechanisms of cell proliferation induced by low power laser irradiation

    Xuejuan Gao, Da Xing

    5052009
  9. 19

    Low-level laser therapy for wound healing: mechanism and efficacy

    William Posten, David A. Wrone, Jeffrey S. Dover, et al.

    4902006
  10. 20

    Mechanisms of low level light therapy

    Michael R. Hamblin, Tatiana N. Demidova

    4782006

Publication ranking · PBM database

50 most prolific PBM researchers

  1. 01
    Michael R Hamblin(United Kingdom)
    181
  2. 02132
  3. 03120
  4. 04115
  5. 05114
  6. 06103
  7. 07
    Heidi Abrahamse(South Africa)
    99
  8. 0893
  9. 0979
  10. 10
    Rodrigo Álvaro Brandão Lopes-Martins(Brazil)
    77
  11. 1174
  12. 12
    Praveen R Arany(United States)
    74
  13. 1366
  14. 1466
  15. 15
    Jan Magnus Bjordal(Norway)
    64
  16. 1661
  17. 17
    Rodrigo Labat Marcos(Brazil)
    60
  18. 18
    John Mitrofanis(Australia)
    56
  19. 19
    Nicolette N Houreld(South Africa)
    55
  20. 20
    Sufan Chien(United States)
    55
  21. 21
    Abdollah Amini(Iran)
    54
  22. 2254
  23. 2352
  24. 2450
  25. 2549
  1. 26
    F Gonzalez-Lima(United States)
    47
  2. 27
    Manoela Domingues Martins(Brazil)
    47
  3. 28
    Cleber Ferraresi(Brazil)
    45
  4. 2945
  5. 30
    Andrey Jorge Serra(Brazil)
    42
  6. 31
    Paolo Cassano(United States)
    41
  7. 32
    Jin-Chul Ahn(South Korea)
    38
  8. 33
    Regiane Albertini(Brazil)
    38
  9. 3437
  10. 3537
  11. 3637
  12. 3736
  13. 38
    Phil-Sang Chung(South Korea)
    36
  14. 39
    Jared Jagdeo(United States)
    35
  15. 40
    Lucio Frigo(Brazil)
    35
  16. 4135
  17. 4235
  18. 43
    Juanita J Anders(United States)
    34
  19. 44
    Carlos de Paula Eduardo(Brazil)
    33
  20. 4533
  21. 46
    Lívia Assis(Brazil)
    33
  22. 4733
  23. 48
    Da Xing(China)
    32
  24. 4932
  25. 50
    Hanli Liu(United States)
    32

Counts are unique articles in the PBM database; Sunlight records are excluded. Different name forms were merged only when their ORCID and name forms agreed. Countries are inferred from author affiliations; the #1 researcher’s country label is based on public interview information.

PBM Database details

What the published records cover

The analyses below omit the separate “Sunlight” category and use the database snapshot dated 25 September 2026.

Most represented research topics

Ranked by topic labels in the database. Broad record types such as reviews, editorials and protocols are excluded.

Database topicRecordsHumanAnimalIn vitro
01Oral mucositis262149233
02Bone repair20901917
03Tooth extraction163116240
04Orthodontics: Tooth movement16076413
05TMD159108121
06Myopia1548292
07Alzheimer’s disease134245324
08Excision (secondary intention)12901285
09Periodontium (in vitro)11301108
10Tumor cells11212109

Study-model counts can overlap when a record includes more than one model; records without these model labels remain in the total.

Publication size ranking

Largest clinical publications by sample size

Examples of the largest patient, participant or case counts recorded in the database.

  1. 01Diode-laser pain attenuationShiroto · 1989 · Retrospective survey3,635patients
  2. 02Red-light treatment for myopiaChen · 2026 · Prospective multicentre cohort2,825patients
  3. 03LLLT for androgenetic alopeciaQiu · 2022 · Real-world observational study1,383patients
  4. 04904 nm laser for osteoarticular painSoriano · 1995 · Clinical case series938patients
  5. 05LED photomodulation clinical experienceWeiss · 2005 · Clinical experience900patients
  6. 06PBM for oral mucositisPaiva · 2024 · Retrospective cohort751patients
  7. 07LLLT for female infertilityOhshiro · 2012 · Extended clinical case series701patients
  8. 08Laser-assisted liposculptureNeira & Ortiz-Neira · 2002 · Clinical case series700cases
  9. 09PBM after hematopoietic cell transplantationBezinelli · 2021 · 15-year retrospective study693patients
  10. 10Transcranial laser for acute strokeZivin · 2009 · Double-blind randomized trial660patients

Patient, participant and case counts only; treatment-unit counts such as teeth are excluded. Cohort overlap is not deduplicated.

One field, many names

Terminology

Photobiomodulation

Low-level laser therapy

102names & descriptions
used in light therapy

PBM / photo-

11
  • Photobiomodulation
  • Photobioactivation
  • Photobiostimulation (PBM therapy)
  • Photo-enhancement
  • Photoradiation
  • Photostimulation
  • Therapeutic photobiomodulation
  • Photomodulation
  • Photobiotherapy
  • Photobiological modulation
  • Photoregulation of cellular metabolism

Low-level / low-power

22
  • Low-level laser therapy
  • High fluence low-power laser irradiation
  • Low dose laser irradiation
  • Low-energy Helium-Neon laser irradiation
  • Low-energy laser irradiation
  • Low energy light irradiation
  • Low-intensity laser irradiation (LILI)
  • Low-intensity laser therapy
  • Low-level laser
  • Low-level laser energy
  • Low-level light
  • Low-level light therapy
  • Low-power laser therapy
  • Low-power diode laser
  • Low-power laser irradiation (LPLI)
  • Low-power laser stimulation
  • Low-power laser treatment
  • Low power red laser light (LPRLL)
  • Low-level phototherapy
  • Low reactive-level laser therapy
  • Low-intensity light therapy
  • Low-energy photon therapy (LEPT)

Wavelengths

16
  • 660nm LED light source
  • 670nm light
  • λ780 nm laser light
  • 830nm laser
  • 810-nm diode laser
  • Far-red light
  • Far red/near infrared light
  • Laser 904 nm
  • Near infra-red
  • Near-infrared light
  • Near-infrared light treatment
  • Water-filtered infrared-A
  • Red light therapy (RLT)
  • Polychromatic light
  • Monochromatic infrared energy (MIRE)
  • Monochromatic infrared photoenergy (MIPE)

Laser descriptors

17
  • CLASS IV laser therapy
  • Cold laser
  • Cold laser therapy (CLT)
  • Helium-neon laser
  • He-Ne laser
  • Laser light irradiation
  • Laser treatment
  • MID-laser therapy
  • Physiotherapy laser
  • Short pulsed nonablative infrared laser irradiation
  • Soft laser
  • Laser phototherapy
  • Laser biostimulation
  • Laser biomodulation
  • Multiwave Locked System (MLS) laser therapy
  • High-intensity laser therapy (HILT)
  • High-power laser therapy (HPLT)

Light / LED

22
  • Electromagnetic energy
  • Irradiation
  • LED-based red light photo-stimulation
  • LED-light
  • LED phototherapy
  • Light-emitting diode irradiation
  • Light-Emitting Diode Phototherapy
  • Monochromatic phototherapy
  • Nanoparticle-emitted light
  • Narrow-band light
  • Narrow-band red light phototherapy
  • Polarized light therapy
  • Singlet oxygen energy (SOE light)
  • Visible light
  • Bioptron light therapy
  • Polarized polychromatic non-coherent light
  • Organic light-emitting diode therapy (OLED)
  • LED photomodulation
  • Fluorescent light energy (FLE)
  • Biophotonic therapy
  • Superluminescent diodes (sLED)
  • Anodyne light therapy

Applications

14
  • Intravascular red laser therapy
  • Intravascular Low-Power Laser illumination
  • Intravascular low-power red laser light
  • Laser acupuncture
  • Transcranial infrared laser therapy
  • Transcranial Laser Stimulation
  • Transcranial laser therapy (TLT)
  • Transcranial low level laser (light) therapy
  • Photoneuromodulation
  • Intranasal photobiomodulation
  • Transdermal photobiomodulation
  • Sublingual laser blood irradiation
  • Intravenous laser blood irradiation (ILBI)
  • Transcranial infrared laser stimulation (TILS)
A curated terminology collection, grouped by naming style. Includes light-source descriptions and related therapies.