Red Light Therapy
Photobiomodulation · Panels & LED Masks
Evidence grade 4 of 5, Strong. Read how the Atlas grades evidence.
The record counts 40 randomised controlled trials in people, including pooled analyses that agree across indications: seven sham-controlled RCTs of home devices for pattern hair loss (SMD 1.27), four multicentre double-blind lasercomb trials with 141 women randomised showing greater terminal hair density at 26 weeks, a 136-volunteer controlled skin trial, a 137-woman split-face periocular RCT, a 60-person sham-controlled crow's feet trial, and a six-RCT acne meta-analysis of 216 participants. Open questions remain: dosimetry was challenged, running-performance PBM showed no effect, and muscle-soreness evidence is low certainty.
Counted on the record: 31 human studies, 28 randomized trials, 800 participants, 2 animal studies, 1 lab study.
The dataset includes 28 randomized human trials covering hair loss (10), acne (6), skin rejuvenation (4), vision (6), and safety (2), plus three additional human studies or reports, animal experiments, and laboratory research. However, a 2025 review identified 204 randomized trials through 2023, meaning this dataset is incomplete and the total number of participants remains unverified.
- FDA
- Class III medical devices: cleared for safety
- WADA
- Surface LED or laser photobiomodulation is not on the WADA Prohibited List and is permitted in competition. Intravenous laser blood manipulation would fall under M1.3, but that is unrelated to at-home panels and masks.
Reference only. Not medical advice.
What can go wrong
Red light therapy is generally low-risk when used correctly, but eye exposure is the primary safety concern, particularly with near-infrared light (810–850 nm), which can reach the retina. Protective eyewear is recommended, and misuse or device malfunction can cause burns or blistering. At-home devices are not established treatments for serious medical conditions, and individuals taking photosensitizing medications, with a history of skin cancer, who are pregnant, or who have diagnosed medical conditions should consult a physician before use.
Red light therapy has demonstrated biological effects, although its exact mechanism remains uncertain. Clinical evidence is strongest for hair regrowth, with supportive results for skin rejuvenation and mild-to-moderate acne, while muscle recovery and athletic performance benefits remain inconclusive. Studies vary widely in dosing, devices, and quality, so consumer products may not reproduce clinical results, and marketing claims often exceed the available evidence.
Real mitochondrial mechanism, genuine skin and soreness signals, marketing that sprints ahead of the data.
What people take it for
What it is taken for. Approval, where it exists, covers only some of these.
How it works
Red light therapy uses low-intensity red or near-infrared light (600–1100 nm) to stimulate cellular processes, primarily by targeting mitochondria and potentially increasing ATP (cellular energy) production. Proposed downstream effects include changes in nitric oxide, reactive oxygen species, and cell signaling pathways involved in tissue repair, inflammation, and nerve protection. These are proposed to switch on signalling pathways and transcription factors, which reviews name as PI3K/Akt, MAPK and NF-kB. Its effects depend on wavelength and dose, with higher doses potentially being ineffective or inhibitory, and the underlying mechanisms remain incompletely understood, with most evidence coming from cell and animal studies.
- Step 1Light enters tissueLow intensity red or near infrared light, about 600 to 1100 nm, is applied to the skin or tissue.
- Step 2Photon absorptionReviews propose that cytochrome c oxidase in mitochondria absorbs the light. Light-sensitive ion channels are also suggested.
- Step 3Nitric oxide releaseOne hypothesis is that light frees nitric oxide bound to the enzyme, which lifts a brake on respiration.
- Step 4Energy output risesThe mitochondrial energy chain is described as running faster and producing more ATP.
- Step 5Signalling burstA short rise in reactive oxygen species, along with nitric oxide and calcium changes, is said to act as a cell signal.
- Step 6Pathways switch onSignalling routes such as PI3K/Akt, MAPK and NF-kB are reported to be activated, changing gene activity.
- Step 7Tissue-level effectsReviews link these changes to tissue repair, reduced inflammation and nerve protection, mostly in lab and animal work.
- Step 8Dose shapes responseThe response is described as biphasic: low doses stimulate, while high doses may do nothing or inhibit.
The proposed mechanism of red light therapy remains unproven in humans (too few trials), with most supporting evidence coming from cell and animal studies. Effectiveness varies by wavelength, dose, and device, with inconsistent clinical results and no demonstrated benefit for running performance. Safety concerns also exist, including reported retinal damage from repeated eye exposure in children.
Not a compound: red and near-infrared light, usually from LEDs or lasers.
Light is made at the moment of use, so it cannot be stored and does not keep. What can change is the device: a 2025 bench test of five home LED devices bought online found that power output was unstable over time and that wavelength, power and intensity varied widely between devices. That was a lab test of devices, not a study in people.
Not a one-size-fits-all treatment
Results depend on the wavelength, intensity, exposure time, and amount of light actually reaching the target tissue, so benefits observed with one device or condition cannot be assumed for another. Human studies support certain applications, including some forms of hair loss and skin treatment, but broader claims about recovery, metabolism, and performance require stronger clinical evidence.
How it is taken
Topical or transdermal.
Safety in detail
- Two Phase I skin trials (STARS 1 and 2) found dose-limiting redness and blistering in three participants at 480–640 J/cm², with darker skin showing greater sensitivity. Six acne trials (216 participants), four hair-loss trials, and a small under-eye study reported no serious adverse events, although follow-up was limited to 6–26 weeks. A 2023 eye case report documented vision declining from 20/20 to 20/30, while a 2025 trial found temporary retinal changes in 7% of treated children (3/43).
What people get wrong
Often saidRed light therapy is FDA-approved to cure wrinkles, pain, and hair loss.
ActuallyThere is no FDA approval for general red light wellness. Specific devices hold 510(k) clearances for narrow indications: the HairMax LaserComb is cleared for androgenetic alopecia, and certain LED masks are cleared for wrinkles or acne. Clearance signals reasonable safety and substantial equivalence to an existing device, not a proven cure, and most panels are sold as unregulated general-wellness products (FDA 510(k) records; FDA device classification).
Often saidMore power and longer sessions always mean better results.
ActuallyThe dose-response in photobiomodulation is biphasic: too little does nothing and too much can blunt or reverse the effect, so stronger and longer is not automatically better (Huang, Sharma, Carroll and Hamblin, Dose-Response 2011).
Often saidAt-home masks match what dermatologists use in clinic.
ActuallyClinic devices generally deliver much higher irradiance, so at-home units are weaker and published clinical results may not transfer directly. Consumer devices are also where regulators have flagged the most overclaiming (American Academy of Dermatology guidance; FTC health-products guidance).
Often saidIt boosts athletic performance.
ActuallyPre-exercise photobiomodulation is associated with reduced next-day muscle soreness on low-certainty evidence, but a 2024 meta-analysis of running-performance RCTs found no significant ergogenic effect, and performance benefits remain contested (systematic reviews, 2024).
Who profits, and who pushes back
Joovv
Sells this. Has a commercial interest in a product sold as this compound, as of July 2026.
PAID. Sells the devices; markets 510(k) clearance and recovery and skin benefits.
Michael Hamblin
Leading PBM scientist whose mechanistic reviews are widely cited; has consulted in the field, so independence is not absolute.
Harry T. Whelan
Led NASA-funded LED wound-healing research in the 1990s; academic, not selling consumer panels.
Peter A. Jenkins
Argued that the reported irradiance and radiant-exposure values in the headline periocular wrinkle RCT are internally inconsistent, recalculating a lower delivered dose than the authors stated and cautioning that this undermines confidence in the reported effect size.
American Academy of Dermatology
Notes that consumer red light claims often outpace the evidence and that at-home devices are weaker than clinical ones, so benefits for many advertised uses remain unproven.
Federal Trade Commission
In its 2020 Willow Curve settlement, held that the marketers lacked scientific evidence for claims that the light device was clinically proven and FDA-approved to treat chronic severe pain and inflammation.
Where the research comes from
| Place | Share of published research |
|---|---|
| North America | 40% |
| Asia | 33% |
| Europe | 22% |
| Rest of world | 5% |
Research published from: Hungary (origin); USA, Brazil, South Korea, China lead device research and manufacturing.
How we got here
The history runs from early light treatment and laser research through clinical trials, device clearances and consumer products. Recent entries include eye-directed myopia studies, retinal safety reports and broader evidence reviews. The timeline emphasizes that eye-directed myopia devices are not interchangeable with ordinary red-light wellness panels.
Modern red light therapy originated in Hungary in 1967, when physician Endre Mester discovered that low-power laser light stimulated hair growth in mice, leading to further wound-healing research. In the 1990s, NASA-supported LED research helped advance the technology, eventually contributing to today's red and near-infrared light therapy devices.
The timeline begins with Finsen's 1903 Nobel Prize for treating lupus vulgaris with concentrated light, followed by the invention of the laser and Mester's mouse findings. Research later covered proposed cellular mechanisms, NASA-linked LED and wound-healing work, clinical trials, hair-device clearances and consumer panels. More recent entries include eye-directed myopia research and retinal safety reports, while the timeline distinguishes these devices from ordinary red-light wellness panels and notes that FDA registration is not FDA clearance.
Foundations and early laboratory research
1903 to 1993
The timeline begins with Finsen's light treatment and the invention of the laser, then records Mester's mouse findings. Later entries trace proposed cellular mechanisms and NASA-linked LED research.
- 1903Finsen's Nobel Prize for light treatmentNiels Finsen received the Nobel Prize for treating lupus vulgaris with concentrated light, a precursor to modern red-light therapy.
- 1960The first working laserTheodore Maiman demonstrated the first working laser.
- 1967Mester's light-stimulation findings in miceLow-powered laser exposure unexpectedly stimulated hair growth in mice and led to wound-healing research.
- 1968Mester publishes mouse findingsMester published the incidental hair-regrowth and wound-healing findings.
- 1989Karu's light-cell mechanismsA review of cellular light responses helped establish mitochondrial chromophores as a proposed mechanism, still not fully proven.
- 1993NASA-linked red LED researchRed LED systems for plant growth eventually led to NASA-funded cell and wound-healing research.
Mechanisms, clinical trials and clearances
2001 to 2014
This period includes reports on cellular mechanisms and wound healing, followed by hair and skin trials and FDA clearances. The entries cover specific indications and devices, not a general clinical breakthrough.
- 2001Karu identifies a proposed photoacceptorKaru's work identifies cytochrome c oxidase as the primary photoacceptor in light responses.
- 2001NASA LED wound-healing reportWhelan and colleagues reported cell culture work, rodent wound models and early human observations.
- 2007HairMax LaserComb clearance for menThe FDA cleared the HairMax LaserComb for promotion of hair growth in men with androgenetic alopecia.
- 2007Split-face skin rejuvenation trialA randomized study of 76 people tested 633-nm and 830-nm LEDs and reported improved skin measures.
- 2009HairMax randomized trialA 26-week sham-controlled trial reported improved terminal hair density in men with pattern hair loss.
- 2009Omnilux Clear-U clearanceThe FDA cleared an over-the-counter light-based acne device.
- 2011HairMax clearance expands to womenHuang, Hamblin and colleagues described a biphasic dose response, and the FDA cleared HairMax for female pattern hair loss.
- 2013Hair-growth helmet trialA randomized trial of 40 people tested a helmet emitting 630-, 650- and 660-nm light and found higher hair density than with sham treatment.
- 2014HairMax trials and controlled skin studyMulticenter sham-controlled hair trials involving 269 randomized men and women found greater hair-count gains after 26 weeks. A separate controlled trial reported improvements in collagen density, fine lines and roughness.
Consumer devices and broader evidence
2016 to 2020
Consumer panels and modular devices became more prominent alongside evidence reviews. The timeline also records an FTC settlement over claims for a low-level light therapy pain device.
- 2016Photobiomodulation term adoptedThe term photobiomodulation was formally adopted to replace low-level laser therapy.
- 2016Joovv launches home light panelsJoovv began selling consumer full-body red-light panels, a commercial milestone rather than a clinical breakthrough.
- 2018Joovv modular panelsJoovv introduced expandable modular panels designed for at-home full-body exposure.
- 2019Hair-loss meta-analysisA review of 15 controlled studies involving 795 participants found significant mean hair-density gains for androgenetic alopecia.
- 2020FTC settlement over Willow CurveThe FTC settled its first low-level light therapy case over the Willow Curve pain device, stopping deceptive clinically proven and FDA-approved pain and inflammation claims.
Eye-directed research, safety reports and social media
2022 to 2024
The timeline records clinical research into red-light devices directed at the eyes, alongside retinal injury reports and a review of child eye-safety evidence. It also includes hair, exercise and social-media milestones.
- 2022Childhood myopia RCTIn a 264-child trial, specialized 650-nm eye-directed devices slowed eye elongation versus glasses over 12 months.
- 2022Meta-analysis of home hair devicesA meta-analysis of seven randomized trials reported significant hair-density gains with FDA-cleared home light devices for pattern hair loss.
- 2023Myopia prevention RCT Sham-controlledA study of 278 children at risk for myopia reported lower new-onset myopia with repeated low-level red-light use and a randomized trial of 112 children reported reduced axial elongation over six months.
- 2023Retinal injury case reportA case report described retinal damage in a child after repeated direct-to-eye red-light treatment, highlighting the need for monitoring.
- 2023Periocular wrinkle trial and responseA 137-woman split-face trial reported about a 30% reduction in periocular wrinkle volume with red and amber photobiomodulation. Jenkins published a critical response challenging the reported dosimetry.
- 2024High-myopia pediatric trialA randomized trial in 192 children and adolescents extended research to severe myopia.
- 2024Running performance reviewA meta-analysis of 12 trials found no significant running-performance gains. Separate evidence for pre-exercise soreness was low-certainty.
- 2024TikTok LED-mask boomLED-mask content went viral, and the hashtag “Red LED light therapy” exceeded 70 million views by February 2024.
Recent evidence and safety questions
2025 to 2026
Recent entries include an acne evidence review, an FDA warning and testing of consumer device output. Later myopia reviews and retinal reports keep the timeline's eye-safety questions in view.
- 2025Acne meta-analysis and FDA warningA meta-analysis supported at-home LED for mild-to-moderate acne. The FDA warned Spectra Therapy that its infrared system was marketed for diseases outside its cleared use without supporting evidence.
- 2025Home LED device output testTesting of five consumer devices found that output, beam spread and dose delivery varied widely.
- 2026Pediatric myopia meta-analysis of all trials (Primarily China)A review pooling 28 randomized trials with 3,573 children found less myopia progression but called for longer retinal safety follow-up.
- 2026Additional retinal case reportA report described subretinal fluid and mild vision loss in an 11-year-old after prolonged eye-directed exposure.
The people taking it
Adults buying home LED and laser devices for skin and hair, people with acne or pattern hair loss, people using it for muscle soreness or pain, and in China, children treated for nearsightedness or lazy eye.
No authoritative global count of red light therapy users was found. In the United States, the polling firm CivicScience reported that 16% of US adults said they had used red light therapy. This is a commercial online poll, not a peer-reviewed or government survey, and it does not separate clinic use from home use or say how often people use it. A 2020 meta-analysis noted that only 32 home-use light and laser hair devices had been cleared by the FDA as of January 2020. That counts devices, not users.
Red light therapy has been studied across different age groups and conditions, although comprehensive user demographics are unavailable. A consumer survey found that 60.4% learned about red light devices through social media, while **90%** expressed interest in purchasing a home device. Clinical trials have included individuals aged 12–50 with acne, adults aged 30–65 for skin rejuvenation, men and women with pattern hair loss, and school-aged children in China receiving eye-directed treatment for myopia. A separate US commercial poll reported that over 25% of red light therapy users surveyed** had also undergone elective cosmetic or weight-loss surgery.
Red light therapy originated in Hungary in 1967 and is now used in the US, China, South Korea, and Europe. Clinical studies cover acne, skin rejuvenation, hair loss, and myopia, while FDA clearances apply to specific devices and indications. Social media has increased consumer interest, but regulators have challenged unsupported claims, and eye-directed treatments have raised retinal safety concerns.
What we do not know
- Do the acne benefits seen with at-home red and blue LED devices last, and is longer use safe? The trials pooled in the 2025 meta-analysis ran for 12 weeks at most and were small.
- Does red light add anything over blue light alone for acne? In one small open-label trial, a combined red and blue device did not reduce lesions significantly more than a blue-only device when the two were compared directly.
- Why do results for non-inflammatory acne lesions vary so much between at-home LED studies?
- How much light do consumer home devices actually deliver to tissue? A bench study of five devices bought online found wide differences in output, unstable power and dosing directions that ignore beam spread and light lost in tissue.
- Light effects are described as biphasic, with lower doses stimulating and higher doses inhibiting. What dose range is useful for each condition in people, and can a user overshoot it with a consumer device?
- Are red light doses that are safe on the skin of healthy forearms over 3 weeks also safe on other body areas, with longer use, and across all skin types? Darker skin appeared more sensitive in the safety trials.
- Is repeated low-level red light shone into children's eyes for myopia safe over the long term? A case report described retinal damage, and a trial found temporary retinal changes on OCT scans.
- Some laser-based myopia devices reached safety exposure limits within seconds in laboratory testing. Will independent safety testing confirm which devices, if any, are safe for routine use in children?
- How much of the cell and mitochondrial mechanism described in reviews, involving cytochrome c oxidase, ATP and reactive oxygen species, has been confirmed in human tissue rather than in cell culture or animals?
- Are the improvements in wrinkles reported in trials of LED masks and panels meaningful and durable? Some studies were small, had no control group or relied on self-report, and one trial's reported dosimetry was challenged in a published response.
- Which device features, such as wavelength, laser versus LED, and comb versus helmet, matter for hair regrowth in pattern hair loss, and do the effects last beyond 26 weeks?
- Does photobiomodulation improve exercise performance or recovery? A meta-analysis of running trials found no significant effect, and evidence on muscle soreness is of low certainty.
At a glance
- Key wavelengths
- Red about 630 to 660 nm, near-infrared about 810 to 850 nm
- Photoacceptor
- Cytochrome c oxidase in mitochondria
- Strongest evidence
- Skin (wrinkles, collagen) and pre-exercise muscle soreness
- TikTok signal
- Beauty-tech sales up about 400% on TikTok Shop, 2024 to 2025
What this entry does not yet cover
What follows is unfinished work on our side, not a finding about Red Light Therapy. A short entry is not a safe entry.
- Cost and market. We have not documented what it sells for or who sells it.
- Supply chain. We have not mapped where it is made.
- What could change. No forward-looking summary yet.
- How it compares. We have not set it against the alternatives.
- Children and teenagers. We have not checked what is known about younger people.
Sources
A meta-analysis of seven sham-controlled randomized trials in the Journal of Clinical and Aesthetic Dermatology found significantly increased hair density in pattern hair loss with FDA-cleared home light devices (standardized mean difference 1.27). Hair growth increased in both men and women and with both comb-style and helmet-style devices. Devices using laser diodes alone showed a larger difference from sham devices (standardized mean difference 1.52) than laser diode combinations (0.85), a difference that was statistically significant. As of January 2020, only 32 home-use light and laser devices of this kind had been cleared by the FDA, and very few studies support the efficacy of home devices on the market generally.
Journal of Clinical and Aesthetic Dermatology (Dodd et al.), via PubMed
The 2014 Jimenez study in the American Journal of Clinical Dermatology reports four multicenter, randomized, double-blind trials comparing HairMax LaserComb models with inactive sham devices in men and women with pattern hair loss, with hair counts measured after 26 weeks. Across the four trials, people using the lasercomb had a significantly larger increase in terminal hair density—the number of thick, mature hairs in an area of scalp—than people using the sham device (p < 0.0001), and this increase did not depend on age, sex, or which lasercomb model was used. No serious adverse events were reported in anyone who used the lasercomb; however, these were short trials of 26 weeks and do not show longer-term safety.
Jimenez et al., multicenter randomized sham-controlled study, via PubMed
A 2014 controlled trial in Photomedicine and Laser Surgery tested red and near-infrared light from two new sources covering large body areas with mixed wavelengths and no heating in 136 volunteers compared with 23 controls. After 30 sessions, blinded reviewers rating clinical photographs found significant improvement in the treated groups, and ultrasound measurement showed about 31% improvement in collagen density along with improvements in fine lines and roughness. Volunteers also reported significantly improved skin complexion and skin feeling, though the abstract gives no information on follow-up after the 30 sessions.
Photomedicine and Laser Surgery (Wunsch, Matuschka), SAGE/Liebert
137-woman split-face RCT reported about 30% periocular wrinkle-volume reduction with red and amber PBM
Mota, Pavani et al., Photobiomodulation, Photomedicine, and Laser Surgery, via PubMed
Jenkins published response challenging the reported dosimetry of the periocular wrinkle RCT
Peter A. Jenkins, Photobiomodulation, Photomedicine, and Laser Surgery, via PubMed
2025 meta-analysis of six RCTs (n=216) supports at-home red and/or blue LED for mild-to-moderate acne
JAMA Dermatology systematic review and meta-analysis, via JAAD clinical review
Randomized comparison of red vs blue light for mild-to-moderate acne showed similar efficacy, with red better tolerated
Comparison of red and blue light for acne vulgaris RCT, via PubMed
Low-certainty evidence that pre-exercise PBM reduces delayed-onset muscle soreness; heterogeneity high, extractable data sparse
Systematic review and meta-analysis of photomodulation for DOMS (2025), PMC
Meta-analysis of running-performance RCTs found no significant ergogenic effect of PBM and no dose-response
Cytochrome c oxidase is the primary photoacceptor and the dose response is biphasic (low stimulates, high inhibits)
Huang, Sharma, Carroll, Hamblin, Dose-Response (Biphasic Dose Response in Low Level Light Therapy)
FTC settled its first low-level light therapy case (Willow Curve), stopping deceptive clinically-proven and FDA-approved pain and inflammation claims
FDA warned Spectra Therapy (July 2025) that its LASERwrap infrared system was marketed for diseases outside its cleared use with no supporting evidence
Real-world study of an FDA-cleared laser helmet reported about 80% self-assessed effectiveness across 1,383 pattern-hair-loss patients
Efficacy assessment of LLLT for androgenetic alopecia, real-world study, PMC
Endre Mester discovered light biostimulation in mice in 1967 at Semmelweis University, Budapest, publishing in 1968
The Nuts and Bolts of Low-level Laser Therapy (history review), PMC
A review titled "What Lies at the Heart of Photobiomodulation: Light, Cytochrome C Oxidase, and Nitric Oxide" examines the evidence for the idea that light works on cells through cytochrome c oxidase and nitric oxide. Cytochrome c oxidase is an enzyme in mitochondria, the parts of the cell that make energy. This claim rests on the review's printed title. The review's conclusions, authors and year were not read for this entry.
A multicenter randomized trial in children tested repeated low-level red-light therapy for controlling myopia, or nearsightedness. Its abstract describes a parallel-group, single-blind design, which means the children were split into separate groups and one side of the study did not know which group was which. The trial's results and number of children were not read for this entry, and the displayed title is cut off.
Effect of Repeated Low-Level Red-Light Therapy for Myopia Control in Children: A Multicent...
Yan Xu, Lipu Cui and colleagues report a randomized clinical trial of repeated low-level red light therapy for myopia control in children and adolescents with high myopia, meaning strong nearsightedness. The trial's results and number of participants were not read for this entry.
In a study in chicks, Chengjie He and colleagues gave the birds myopia by fitting them with lenses. The title of their paper states that repeated low-level red light changed how the retina's energy metabolism shifted in these chicks. This is an animal study and says nothing directly about people. Its methods and results were not read for this entry.
A randomized, parallel-group study tested repeated low-level red-light therapy for eye strain symptoms and for the eye's ability to adjust focus in people with presbyopia, the age-related loss of near focus. The study's results were not read for this entry, and the displayed title is cut off.
Repeated low-level red-light therapy for improving asthenopic symptoms and accommodation i...
A 2026 review article titled 'Mechanisms of action and clinical research progress of photobiomodulation' (Shi et al., Journal of Photochemistry and Photobiology B, 2026) describes photobiomodulation as the use of low intensity visible or near infrared light, in the 600 to 1100 nanometer range, applied to tissue. The review states that this light is absorbed by a protein inside cell mitochondria called cytochrome c oxidase, and that this absorption activates the cell's energy-making chain, raises ATP output, and adjusts levels of reactive oxygen species, which in turn switches on cell signaling pathways the review names as PI3K/Akt, MAPK, and NF-kB. The review describes these effects as changing with the light's wavelength and dose, calling the pattern bidirectional. It organizes its summary of the research into five areas: tissue repair and regeneration, anti-inflammatory and immune effects, regulation of glucose and lipid metabolism, use alongside cancer therapy, and nerve protection and repair. The review itself is a synthesis of previously published research rather than a new laboratory or clinical study, and the readable portion of its abstract does not say which of these described findings come from cell culture (in vitro) work, animal (in vivo) studies, or human studies; that breakdown is not stated in the text that could be read.
Mechanisms of action and clinical research progress of photobiomodulation - PubMed
A 2025 systematic review and meta-analysis in JAMA Dermatology pooled six randomized clinical trials of at-home or portable red and/or blue LED devices for acne in 216 participants aged 12 to 50 years with mild to moderate acne. Compared with control groups, the LED devices showed greater percent change in inflammatory acne lesions (45.3%), non-inflammatory lesions (47.7%), and investigator-rated overall acne improvement (45.7%), though results for non-inflammatory lesions varied substantially between studies and each outcome rested on only four or five small studies. None of the trials reported severe adverse reactions; the few participants with side effects reported mild dryness, redness, or discomfort during treatment. Since trials lasted 12 weeks at most, effects of longer use are unknown.
At-Home LED Devices for the Treatment of Acne Vulgaris: A Systematic Review and Meta-Analysis
A 2025 randomized, double-blind, sham-controlled trial by Park, Park and Jung enrolled 60 adults of Asian descent aged 30 to 65 years with crow's feet wrinkles and Fitzpatrick skin types II to V at two Korean institutions. Participants used either a home mask combining 630 nm red LED light and 850 nm near-infrared light at a maximum intensity of 10 mW/cm³ or a sham mask for 12 weeks with assessments continuing for 4 weeks afterward. Independent raters and investigators both scored wrinkle grades as significantly different between the LED mask group and the sham group at 8, 12, and 16 weeks, though the difference was not significant at 4 weeks in the per-protocol group. The authors report that 86.2% of the full analysis group showed improvement with the LED mask, which was 69.5% more than in the sham group, meeting the trial's preset success criteria, and they conclude the mask was effective, safe, well tolerated, and painless.
A 2013 double-blind, randomized, sham-controlled trial in Korea assigned 35 patients with mild to moderate acne to home-use blue-red LED phototherapy or a sham device, with treatment consisting of 420 nm blue light and 660 nm red light applied to the forehead and cheeks twice daily for 4 weeks, followed by observation to 12 weeks. At the final visit, inflammatory acne lesions in the LED group had fallen by 77% and non-inflammatory lesions by 54%, while the sham group showed no significant change. Histological findings in the LED group included lower skin oil output, fewer inflammatory cells, and smaller oil glands, with reduced staining for several inflammation and oil production markers including interleukin-8, interleukin-1 alpha, matrix metalloproteinase-9, toll-like receptor 2, NF-kappa B, the IGF-1 receptor, and SREBP-1, as well as decreased activity of the SREBP-1c gene. No severe adverse reactions were reported, and compliance with the home device was described as good.
An open-label randomized trial published in Dermatologic Surgery in 2026 compared an investigational device combining 660 nm red and 415 nm blue LED light with a commercially available 415 nm blue LED device for at-home treatment of mild to moderate inflammatory acne over 8 weeks in 23 participants. Within each group, total acne lesions fell significantly at 4 and 8 weeks with the combined red and blue device, while they did not fall significantly with the blue-only device; inflammatory lesions fell significantly with both devices at both timepoints, but non-inflammatory lesions did not change significantly with either device. When the devices were compared directly, there was no significant difference in the reduction of total, inflammatory, or non-inflammatory lesions at any timepoint, though the investigator's overall acne rating was significantly lower with the red and blue device at 8 weeks.
Jagdeo and colleagues conducted two phase I, single-blind, dose-escalation randomized controlled trials testing the safety of high-dose LED red light on healthy volunteers' forearms exposed three times a week for 3 weeks, published in the Journal of Biophotonics in 2019 and 2020. STARS 1 enrolled 60 people of all skin types at doses of 160 to 640 joules per square centimeter, while STARS 2 enrolled 55 non-Hispanic Caucasian people at 480 to 640 joules per square centimeter. Side effects that set a dose limit, including blistering and long-lasting redness, occurred at 480 joules per square centimeter in one STARS 1 participant and at 640 joules per square centimeter in two STARS 2 participants, while short-lived redness and darkening of the skin were mild and no serious adverse events occurred. The authors concluded that LED red light was safe up to 320 joules per square centimeter for skin of color and up to 480 joules per square centimeter for non-Hispanic Caucasian individuals, noting that darker skin appeared more sensitive to the light, though these limits derive from only 3 weeks of forearm exposure in healthy adults and do not describe other body areas or longer use.
Safety of light emitting diode-red light on human skin: Two randomized controlled trials
A 2024 study by Wang and colleagues in Archives of Dermatological Research had 11 participants treat themselves for six weeks with a commercially available under-eye LED device emitting red light at 633 nm and near-infrared light at 830 nm. Standardized photographs showed under-eye wrinkle scores moving from 20.05 to 19.72, a change that was not statistically significant. However, all 11 participants reported improvements in under-eye wrinkles, texture, dark circles, bags, pigmentation and redness, and all reported high comfort, ease of use and satisfaction with the device. Participants reported no moderate or severe adverse events, with a few reporting short-lived mild redness. These self-reported improvements came from 11 people with no control group.
Outstanding user reported satisfaction for light emitting diodes under-eye rejuvenation
A 2025 pilot study in the Dentistry Journal tested five hand-held and intra-oral LED photobiomodulation devices bought online for home use by measuring their light output, beam spread, light intensity, and heat generation in pig tissue samples, then comparing these measurements with manufacturers' instructions. The five devices varied widely in wavelength, power output and light intensity, with unstable power output over time and beams that spread at 74 degrees. The authors found manufacturers' dose directions inconsistent with delivering an accurate dose, concluding that the proposed dosing does not account for beam spread or for light lost as it scatters and is absorbed in tissue. This was a bench test of devices, not a study in people.
Photobiomodulation LED Devices for Home Use: Design, Function and Potential: A Pilot Study
A 2023 case report described a 12-year-old girl whose best-corrected vision fell from 20/20 to 20/30 in both eyes, with damage to the light-sensing layer at the centre of the retina on OCT, after 5 months of red light shone into the eyes for nearsightedness; 3 months after stopping, vision was 20/25 and the damage had partly recovered.
In a randomized trial of children with early signs of nearsightedness, 3 of 43 (7%) given red light shone into the eyes showed a temporary bright spot at the centre of the retina on OCT scans, with no symptoms or loss of vision, while none of the 43 controls showed this finding and all cases cleared 0.5 to 3 months after treatment stopped. Laboratory testing against US safety standards found that two laser-based myopia devices reached the safety limit within 2.8 and 1.4 seconds for a 7 mm pupil, far inside the recommended 3-minute session, while an LED-based device took 22,761 seconds, leading the authors to call for independent safety testing before wide use in children.