{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,14]],"date-time":"2026-10-14T23:12:12Z","timestamp":1792019532489,"version":"4.4.0"},"reference-count":42,"publisher":"Public Library of Science (PLoS)","issue":"9","license":[{"start":{"date-parts":[[2025,10,1]],"date-time":"2025-10-01T00:00:00Z","timestamp":1759276800000},"content-version":"vor","delay-in-days":0,"URL":"http:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/100010269","name":"Wellcome Trust","doi-asserted-by":"publisher","award":["214461\/A\/18\/Z"],"award-info":[{"award-number":["214461\/A\/18\/Z"]}],"id":[{"id":"10.13039\/100010269","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":["www.plosone.org"],"crossmark-restriction":false},"short-container-title":["PLoS One"],"abstract":"\nBackground<\/jats:title>\nThe advent of mass-market Light Emitting Diodes (LEDs) has seen considerable interest in potential dermatological applications of LED light photobiomodulation (PBM) for a range of conditions, with a thriving market for direct-to-consumer LED treatments, including red light, blue light, and yellow light wavelengths. Evidence of efficacy is however mixed, and studies report a wide range of irradiances and wavelengths as well as outcome measures, rendering interpretation, comparison, and even efficacy evaluation prohibitive and impeding evidence synthesis.<\/jats:p>\n<\/jats:sec>\n\nMethods<\/jats:title>\nThis work establishes a model for comparing patient received doses, applying this to existent studies to ascertain potential inhomogeneity in reported doses and wavelengths employed. Patient doses were contrasted to equivalent solar exposure time needed to achieve fluences reported at specified wavelengths in the red light (RL), blue light (BL), and yellow light (YL) portion of the spectrum, yielding a comparison of reported doses to typical solar irradiance at the Earth\u2019s surface. Methodological aspects including dose validation, blinding, and bias were also analysed.<\/jats:p>\n<\/jats:sec>\n\nResults<\/jats:title>\n27 relevant studies for dermatological conditions including acne vulgaris (n<\/mml:mi><\/mml:mrow>=<\/mml:mo>9<\/mml:mtext><\/mml:mrow><\/mml:mrow><\/mml:math><\/jats:alternatives><\/jats:inline-formula>, 33.3%), wrinkle-reduction (n<\/mml:mi><\/mml:mrow>=<\/mml:mo>5<\/mml:mtext><\/mml:mrow>,<\/mml:mo>\u00a0<\/mml:mtext><\/mml:mrow><\/mml:math><\/jats:alternatives><\/jats:inline-formula>18.5%), wound-healing (n<\/mml:mi><\/mml:mrow>=<\/mml:mo>3<\/mml:mtext><\/mml:mrow><\/mml:mrow><\/mml:math><\/jats:alternatives><\/jats:inline-formula>, 11.1%), psoriasis severity (n<\/mml:mi><\/mml:mrow>=<\/mml:mo>3<\/mml:mtext><\/mml:mrow><\/mml:mrow><\/mml:math><\/jats:alternatives><\/jats:inline-formula>, 11.1%), and erythemal index (n<\/mml:mi><\/mml:mrow>=<\/mml:mo>7<\/mml:mtext><\/mml:mrow><\/mml:mrow><\/mml:math><\/jats:alternatives><\/jats:inline-formula>, 25.9%) were assessed. Outcome measures were highly heterogeneous between studies, with total patients ranging from 14 \u2013 105 (median: 26). Fluences and wavelengths used in treatment differed over three orders of magnitude across studies even for the same conditions (0<\/mml:mtext><\/mml:mrow>.<\/mml:mo>1<\/mml:mtext><\/mml:mrow>\u00a0<\/mml:mtext>J<\/mml:mi><\/mml:mrow>\u00a0<\/mml:mtext>c<\/mml:mi><\/mml:mrow>m<\/mml:mi><\/mml:mrow><\/mml:mrow>\u2212<\/mml:mo>2<\/mml:mtext><\/mml:mrow><\/mml:mrow><\/mml:msup>\u2212<\/mml:mo>1<\/mml:mtext><\/mml:mrow>2<\/mml:mtext><\/mml:mrow>6<\/mml:mtext><\/mml:mrow>\u00a0<\/mml:mtext>J<\/mml:mi><\/mml:mrow>\u00a0<\/mml:mtext>c<\/mml:mi><\/mml:mrow>m<\/mml:mi><\/mml:mrow><\/mml:mrow>\u2212<\/mml:mo>2<\/mml:mtext><\/mml:mrow><\/mml:mrow><\/mml:msup><\/mml:mrow><\/mml:math><\/jats:alternatives><\/jats:inline-formula>, median: 4<\/mml:mtext><\/mml:mrow>0<\/mml:mtext><\/mml:mrow>.<\/mml:mo>5<\/mml:mtext><\/mml:mrow>\u00a0<\/mml:mtext>J<\/mml:mi><\/mml:mrow>\u00a0<\/mml:mtext>c<\/mml:mi><\/mml:mrow>m<\/mml:mi><\/mml:mrow><\/mml:mrow>\u2212<\/mml:mo>2<\/mml:mtext><\/mml:mrow><\/mml:mrow><\/mml:msup>)<\/mml:mo><\/mml:mrow><\/mml:math><\/jats:alternatives><\/jats:inline-formula>. Derived equivalent solar time ranged from 0.01-19.35 hours (median: 3.3 hours), with central wavelengths between 405nm (BL) - 660nm (RL). No studies reported any dose validation, 10 (37.0%) were sponsored by the device manufacturer with a further 3 (11.1%) conducted by commercial dermatology practices offering the therapy under investigation. Assessors were unblinded to the treatment\/ control groups in 33.3% (n<\/mml:mi><\/mml:mrow>=<\/mml:mo>9<\/mml:mtext><\/mml:mrow><\/mml:mrow><\/mml:math><\/jats:alternatives><\/jats:inline-formula>), while a further 9 (33.3%) did not have any non-light control group, leaving only 33.3% (n<\/mml:mi><\/mml:mrow>=<\/mml:mo>9<\/mml:mtext><\/mml:mrow>)<\/mml:mo><\/mml:mrow><\/mml:math><\/jats:alternatives><\/jats:inline-formula> with both control group and blinded outcome assessment.<\/jats:p>\n<\/jats:sec>\n\nConclusions<\/jats:title>\nResults of this analysis suggest that fluences, wavelengths, and effective dose vary inconsistently between studies with often scant biological justification. This analysis suggests that better dose quantification and understanding of the underlying biophysics as well as plausible biological justifications for various wavelengths and fluences are imperative if LED therapy studies for dermatology are to be informative and research replicability improved.<\/jats:p>\n<\/jats:sec>","DOI":"10.1371\/journal.pone.0332995","type":"journal-article","created":{"date-parts":[[2025,10,1]],"date-time":"2025-10-01T17:25:43Z","timestamp":1759339543000},"page":"e0332995","update-policy":"https:\/\/doi.org\/10.1371\/journal.pone.corrections_policy","source":"Crossref","is-referenced-by-count":4,"title":["Methodological issues in visible LED therapy dermatological research and reporting"],"prefix":"10.1371","volume":"20","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-3140-3278","authenticated-orcid":true,"given":"David Robert","family":"Grimes","sequence":"first","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"340","published-online":{"date-parts":[[2025,10,1]]},"reference":[{"issue":"3","key":"pone.0332995.ref001","doi-asserted-by":"crossref","first-page":"239","DOI":"10.1007\/s00403-021-02231-0","article-title":"Home-based devices in dermatology: a systematic review of safety and efficacy","volume":"314","author":"M Cohen","year":"2022","journal-title":"Arch Dermatol Res"},{"issue":"4","key":"pone.0332995.ref002","doi-asserted-by":"crossref","first-page":"438","DOI":"10.1111\/jocd.12371","article-title":"A review of available laser and intense light source home devices: A dermatologist\u2019s perspective","volume":"16","author":"ML Juh\u00e1sz","year":"2017","journal-title":"J Cosmet Dermatol"},{"key":"pone.0332995.ref003","unstructured":"FDA. Guidance document: Photobiomodulation (pbm) devices - premarket notification [510(k)] submissions draft guidance for industry and food and drug administration staff (january 2023). 2023. Available from: https:\/\/www.fda.gov\/regulatory-information\/search-fda-guidance-documents\/photobiomodulation-pbm-devices-premarket-notification-510k-submissions"},{"key":"pone.0332995.ref004","unstructured":"CNBC. Red light therapy is trending on tiktok - heres what to know. 2024. Available from: https:\/\/www.cnbc.com\/2024\/02\/29\/red-light-therapy-is-trending-on-tiktok-heres-what-to-know.html"},{"issue":"4","key":"pone.0332995.ref005","doi-asserted-by":"crossref","first-page":"303","DOI":"10.1111\/phpp.12841","article-title":"Utilization of light-emitting diodes for skin therapy: Systematic review and meta-analysis","volume":"39","author":"LTN Ngoc","year":"2023","journal-title":"Photodermatol Photoimmunol Photomed"},{"issue":"11","key":"pone.0332995.ref006","doi-asserted-by":"crossref","first-page":"3498","DOI":"10.1111\/jocd.14369","article-title":"Application of red light therapy for moderate-to-severe acne vulgaris: A systematic review and meta-analysis","volume":"20","author":"Y Wu","year":"2021","journal-title":"J Cosmet Dermatol"},{"issue":"1","key":"pone.0332995.ref007","doi-asserted-by":"crossref","first-page":"440","DOI":"10.1118\/1.4903963","article-title":"Ultraviolet radiation therapy and UVR dose models","volume":"42","author":"DR Grimes","year":"2015","journal-title":"Med Phys"},{"issue":"3","key":"pone.0332995.ref008","doi-asserted-by":"crossref","first-page":"456","DOI":"10.1001\/jamaoncol.2021.5964","article-title":"Radiofrequency Radiation and Cancer: A Review","volume":"8","author":"DR Grimes","year":"2022","journal-title":"JAMA Oncol"},{"key":"pone.0332995.ref009","unstructured":"Thor Labs. Unmounted led specifications. 2024.https:\/\/www.thorlabs.com\/newgrouppage9.cfm?objectgroup_id=2814"},{"key":"pone.0332995.ref010","doi-asserted-by":"crossref","first-page":"49","DOI":"10.1080\/14764172.2016.1247961","article-title":"Clinical comparison of salicylic acid peel and led-laser phototherapy for the treatment of acne vulgaris in teenagers","volume":"19","author":"MN Alba","year":"2017","journal-title":"J Cosmet Laser Ther"},{"issue":"3","key":"pone.0332995.ref011","first-page":"25","article-title":"Efficacy and Tolerability of a Combined 445nm and 630nm Over-the-counter Light Therapy Mask with and without Topical Salicylic Acid versus Topical Benzoyl Peroxide for the Treatment of Mild-to-moderate Acne Vulgaris","volume":"9","author":"MS Nestor","year":"2016","journal-title":"J Clin Aesthet Dermatol"},{"issue":"4","key":"pone.0332995.ref012","doi-asserted-by":"crossref","first-page":"170","DOI":"10.3109\/14764172.2015.1007064","article-title":"A randomized controlled study for the treatment of acne vulgaris using high-intensity 414\u2009nm solid state diode arrays","volume":"17","author":"C Ash","year":"2015","journal-title":"J Cosmet Laser Ther"},{"issue":"5","key":"pone.0332995.ref013","doi-asserted-by":"crossref","first-page":"246","DOI":"10.1111\/phpp.12098","article-title":"Randomized trial of three phototherapy methods for the treatment of acne vulgaris in Chinese patients","volume":"30","author":"L-H Liu","year":"2014","journal-title":"Photodermatol Photoimmunol Photomed"},{"issue":"5","key":"pone.0332995.ref014","doi-asserted-by":"crossref","first-page":"1088","DOI":"10.1111\/bjd.12186","article-title":"The clinical and histological effect of home-use, combination blue-red LED phototherapy for mild-to-moderate acne vulgaris in Korean patients: a double-blind, randomized controlled trial","volume":"168","author":"HH Kwon","year":"2013","journal-title":"Br J Dermatol"},{"issue":"6","key":"pone.0332995.ref015","doi-asserted-by":"crossref","first-page":"308","DOI":"10.3109\/14764172.2011.630081","article-title":"Clinical efficacy of home-use blue-light therapy for mild-to moderate acne","volume":"13","author":"MH Gold","year":"2011","journal-title":"J Cosmet Laser Ther"},{"key":"pone.0332995.ref016","doi-asserted-by":"crossref","first-page":"45","DOI":"10.1142\/S1793545811001241","article-title":"Phototherapy for mild to moderate acne vulgaris with portable blue and red led","volume":"4","author":"G Liu","year":"2011","journal-title":"J Innovative Optical Health Sciences"},{"issue":"5","key":"pone.0332995.ref017","first-page":"463","article-title":"A prospective, randomized, open and comparative study to evaluate the safety and efficacy of blue light treatment versus a topical benzoyl peroxide 5% formulation in patients with acne grade II and III","volume":"84","author":"LHF de Arruda","year":"2009","journal-title":"An Bras Dermatol"},{"key":"pone.0332995.ref018","first-page":"1228","article-title":"Red light phototherapy alone is effective for acne vulgaris: randomized, single-blinded clinical trial","volume":"33","author":"N Im","year":"2007","journal-title":"Dermatol Surg"},{"issue":"7","key":"pone.0332995.ref019","doi-asserted-by":"crossref","DOI":"10.1111\/srt.13391","article-title":"Reverse skin aging signs by red light photobiomodulation","volume":"29","author":"V Couturaud","year":"2023","journal-title":"Skin Res Technol"},{"key":"pone.0332995.ref020","first-page":"115","article-title":"A randomized, placebo-controlled, single-blinded, split-faced clinical trial evaluating the efficacy and safety of klox-001 gel formulation with klox light-emitting diode light on facial rejuvenation","author":"A Nikolis","year":"2016","journal-title":"Clin Cosmet Investig Dermatol"},{"issue":"4","key":"pone.0332995.ref021","doi-asserted-by":"crossref","first-page":"214","DOI":"10.1080\/01676830903043959","article-title":"Non-invasive peri-orbital rejuvenation: radiofrequency dual radiowave energy source (RF) and light emission diode system (LED)","volume":"28","author":"R Migliardi","year":"2009","journal-title":"Orbit"},{"key":"pone.0332995.ref022","doi-asserted-by":"crossref","first-page":"51","DOI":"10.1016\/j.jphotobiol.2007.04.008","article-title":"A prospective, randomized, placebo-controlled, double-blinded, and split-face clinical study on led phototherapy for skin rejuvenation: clinical, profilometric, histologic, ultrastructural, and biochemical evaluations and comparison of three different treatment settings","volume":"88","author":"SY Lee","year":"2007","journal-title":"J Photochem Photobiol B: Biol"},{"key":"pone.0332995.ref023","doi-asserted-by":"crossref","first-page":"6","DOI":"10.1007\/s10103-005-0330-5","article-title":"A single-blinded randomised controlled study to determine the efficacy of omnilux revive facial treatment in skin rejuvenation","volume":"20","author":"J Bhat","year":"2005","journal-title":"Lasers medical science"},{"issue":"5","key":"pone.0332995.ref024","doi-asserted-by":"crossref","first-page":"605","DOI":"10.1097\/DSS.0000000000002195","article-title":"Blinded, Randomized, Controlled Trial Evaluating the Effects of Light-Emitting Diode Photomodulation on Lower Extremity Wounds Left to Heal by Secondary Intention","volume":"46","author":"M Perper","year":"2020","journal-title":"Dermatol Surg"},{"key":"pone.0332995.ref025","doi-asserted-by":"crossref","first-page":"367","DOI":"10.1007\/s10103-014-1666-5","article-title":"Effects of weekly led therapy at 625\u2009nm on the treatment of chronic lower ulcers","volume":"30","author":"CPCM Siqueira","year":"2015","journal-title":"Lasers medical science"},{"issue":"1","key":"pone.0332995.ref026","doi-asserted-by":"crossref","first-page":"49","DOI":"10.1007\/s00403-014-1520-4","article-title":"A clinical study of photodynamic therapy for chronic skin ulcers in lower limbs infected with Pseudomonas aeruginosa","volume":"307","author":"X Lei","year":"2015","journal-title":"Arch Dermatol Res"},{"issue":"1","key":"pone.0332995.ref027","doi-asserted-by":"crossref","first-page":"24","DOI":"10.1159\/000430495","article-title":"Prospective Randomized Long-Term Study on the Efficacy and Safety of UV-Free Blue Light for Treating Mild Psoriasis Vulgaris","volume":"231","author":"S Pfaff","year":"2015","journal-title":"Dermatology"},{"issue":"2","key":"pone.0332995.ref028","doi-asserted-by":"crossref","first-page":"219","DOI":"10.1111\/j.1468-3083.2011.04039.x","article-title":"Efficacy of blue light vs. red light in the treatment of psoriasis: a double-blind, randomized comparative study","volume":"26","author":"MM Kleinpenning","year":"2012","journal-title":"J Eur Acad Dermatol Venereol"},{"issue":"3","key":"pone.0332995.ref029","doi-asserted-by":"crossref","first-page":"251","DOI":"10.1159\/000333364","article-title":"Prospective randomized study on the efficacy of blue light in the treatment of psoriasis vulgaris","volume":"223","author":"A Weinstabl","year":"2011","journal-title":"Dermatology"},{"issue":"2","key":"pone.0332995.ref030","doi-asserted-by":"crossref","first-page":"343","DOI":"10.1007\/s10103-018-2599-1","article-title":"Local and systemic effects of low-level light therapy with light-emitting diodes to improve erythema after fractional ablative skin resurfacing: a controlled study","volume":"34","author":"R Wanitphakdeedecha","year":"2019","journal-title":"Lasers Med Sci"},{"issue":"4","key":"pone.0332995.ref031","doi-asserted-by":"crossref","first-page":"496","DOI":"10.1159\/000448000","article-title":"Prospective, Randomized Study on the Efficacy and Safety of Local UV-Free Blue Light Treatment of Eczema","volume":"232","author":"K Keemss","year":"2016","journal-title":"Dermatology"},{"issue":"5","key":"pone.0332995.ref032","doi-asserted-by":"crossref","first-page":"813","DOI":"10.1111\/j.1524-4725.2009.01137.x","article-title":"Improvement of postfractional laser erythema with light-emitting diode photomodulation","volume":"35","author":"TS Alster","year":"2009","journal-title":"Dermatol Surg"},{"issue":"1","key":"pone.0332995.ref033","doi-asserted-by":"crossref","first-page":"30","DOI":"10.1111\/j.1473-2165.2008.00358.x","article-title":"Use of light-emitting diode photomodulation to reduce erythema and discomfort after intense pulsed light treatment of photodamage","volume":"7","author":"JG Khoury","year":"2008","journal-title":"J Cosmet Dermatol"},{"issue":"2","key":"pone.0332995.ref034","doi-asserted-by":"crossref","first-page":"87","DOI":"10.1080\/14764170701213439","article-title":"The effectiveness and safety of topical PhotoActif phosphatidylcholine-based anti-cellulite gel and LED (red and near-infrared) light on Grade II-III thigh cellulite: a randomized, double-blinded study","volume":"9","author":"GH Sasaki","year":"2007","journal-title":"J Cosmet Laser Ther"},{"key":"pone.0332995.ref035","doi-asserted-by":"crossref","first-page":"164","DOI":"10.1002\/lsm.20455","article-title":"Treatment of radiation-induced dermatitis with light-emitting diode (led) photomodulation","volume":"39","author":"MM DeLand","year":"2007","journal-title":"Lasers Surg Med"},{"key":"pone.0332995.ref036","doi-asserted-by":"crossref","first-page":"165","DOI":"10.1016\/j.mla.2006.06.001","article-title":"Combined visible light and infrared light-emitting diode (LED) therapy enhances wound healing after laser ablative resurfacing of photodamaged facial skin","volume":"21","author":"MA Trelles","year":"2006","journal-title":"Med Laser Appl"},{"key":"pone.0332995.ref037","unstructured":"Toshiba Corporation TEDS. Optical semiconductors isolators\/solid state relay. 2022. https:\/\/toshiba.semicon-storage.com\/content\/dam\/toshiba-ss-v3\/master\/en\/semiconductor\/knowledge\/e-learning\/discrete\/discrete-basic-chap5_en.pdf"},{"key":"pone.0332995.ref038","unstructured":"Davidson MW. Fundamentals of light-emitting diodes (leds) - carl zeiss microscopy online campus. 2023. https:\/\/zeiss-campus.magnet.fsu.edu\/print\/lightsources\/leds-print.html"},{"key":"pone.0332995.ref039","article-title":"Research waste is still a scandal\u2014an essay by Paul Glasziou and Iain Chalmers","volume":"363","author":"P Glasziou","year":"2018","journal-title":"BMJ"},{"issue":"1","key":"pone.0332995.ref040","doi-asserted-by":"crossref","first-page":"231056","DOI":"10.1098\/rsos.231056","article-title":"Is biomedical research self-correcting? Modelling insights on the persistence of spurious science","volume":"11","author":"DR Grimes","year":"2024","journal-title":"R Soc Open Sci"},{"issue":"2","key":"pone.0332995.ref041","doi-asserted-by":"crossref","first-page":"211499","DOI":"10.1098\/rsos.211499","article-title":"The puzzling relationship between multi-laboratory replications and meta-analyses of the published literature","volume":"9","author":"M Lewis","year":"2022","journal-title":"R Soc Open Sci"},{"issue":"4","key":"pone.0332995.ref042","doi-asserted-by":"crossref","first-page":"423","DOI":"10.1038\/s41562-019-0787-z","article-title":"Comparing meta-analyses and preregistered multiple-laboratory replication projects","volume":"4","author":"A Kvarven","year":"2020","journal-title":"Nat Hum Behav"}],"container-title":["PLOS One"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/dx.plos.org\/10.1371\/journal.pone.0332995","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,1]],"date-time":"2025-10-01T17:25:49Z","timestamp":1759339549000},"score":1,"resource":{"primary":{"URL":"https:\/\/dx.plos.org\/10.1371\/journal.pone.0332995"}},"subtitle":[],"editor":[{"given":"Taher","family":"Hatahet","sequence":"first","affiliation":[],"role":[{"vocabulary":"crossref","role":"editor"}]}],"short-title":[],"issued":{"date-parts":[[2025,10,1]]},"references-count":42,"journal-issue":{"issue":"9","published-online":{"date-parts":[[2025,10,1]]}},"URL":"https:\/\/doi.org\/10.1371\/journal.pone.0332995","relation":{},"ISSN":["1932-6203"],"issn-type":[{"value":"1932-6203","type":"electronic"}],"subject":[],"published":{"date-parts":[[2025,10,1]]}}}