Red Light Therapy and Melasma: Dermatology Study Review

Last updated: April 2026

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Quick Answer

Photobiomodulation (PBM) is a non-invasive therapy that uses red and near-infrared light from lasers or LEDs.
PBM shows promise for chronic pain, with significant reductions observed in fibromyalgia and neuropathy across 14 studies.
Whole-body PBM may improve sleep quality, with two studies reporting higher serum melatonin and lower nocturnal heart rate.
However, whole-body PBM has not shown benefits for exercise recovery or performance in five studies reviewed.

Photobiomodulation (PBM), often called red light therapy, is a non-invasive treatment that uses red and near-infrared light. This light comes from lasers or light-emitting diodes (LEDs) and is applied to local areas of the skin. The main goal of PBM is to affect mitochondrial activity and other cellular processes, aiming to create therapeutic benefits. While PBM is being explored for many conditions, our analysis of recent studies focuses on its impact on chronic pain, exercise recovery, and specific eye conditions. For instance, a systematic review found that PBM offers a promising alternative for managing chronic pain, with 14 studies highlighting significant pain reduction, particularly in fibromyalgia and neuropathy Systematic Review on Chronic Pain. We have also examined its role in whole-body applications and its safety profile, which consistently shows a low incidence of adverse events.

What is Photobiomodulation (PBM)?

Photobiomodulation, or PBM, is a non-invasive way to use light for therapeutic purposes. It involves directing red and near-infrared light onto a specific area of the body, typically the skin. This light can come from either lasers or light-emitting diodes (LEDs). The core idea behind PBM is that these specific wavelengths of light can interact with cells, particularly the mitochondria, to trigger various biological responses. This interaction is believed to modulate cellular activity, leading to effects that can help with healing, reduce pain, or improve function. It is a procedure that aims to influence the body's natural processes without breaking the skin.

How PBM Works at a Cellular Level

At its most basic, PBM works by delivering photons, or particles of light, to the body's tissues. These photons are absorbed by chromophores, which are light-sensitive molecules within the cells. A primary chromophore in this process is cytochrome c oxidase, found in the mitochondria. When light is absorbed by cytochrome c oxidase, it can lead to an increase in ATP (adenosine triphosphate) production, which is the main energy currency of cells. This boost in cellular energy can then support various cellular functions, including repair, regeneration, and reduction of inflammation. The red and near-infrared spectrum is used because these wavelengths can penetrate deeper into tissues compared to other colors of light, reaching cells below the skin's surface. The non-invasive nature of PBM means it does not require surgery or medication, making it an attractive option for many.

Types of Light Sources Used in PBM

PBM primarily uses two types of light sources: lasers and LEDs. Lasers provide a concentrated, coherent beam of light. This means the light waves are in sync and travel in the same direction, allowing for precise targeting and deeper penetration into tissues. Low-level laser therapy (LLLT) is a common term for PBM when lasers are used. LEDs, on the other hand, emit a broader, diffused light. While less concentrated than lasers, LEDs can cover larger areas more evenly, making them suitable for whole-body treatments or larger skin surfaces. Both lasers and LEDs operate within the red and near-infrared spectrum, typically ranging from about 600 nanometers (nm) to 1000 nm. The specific wavelength, power, and duration of exposure are all critical parameters that researchers adjust to achieve different therapeutic outcomes. The choice between lasers and LEDs often depends on the specific condition being treated, the depth of penetration required, and the size of the treatment area. For example, a localized issue might benefit from the precision of a laser, while a more widespread condition might use LEDs.

Goals of PBM Therapy

The overarching goal of PBM therapy is to leverage light to improve health and wellness. This can manifest in several ways, depending on the application. For chronic pain management, the aim is to reduce pain intensity and improve functional capacity. In the context of exercise, PBM might be used to enhance performance or speed up recovery. For certain eye conditions, the goal is to halt or even reverse disease progression. Across all these applications, PBM seeks to modulate mitochondrial activity and other cellular processes to restore balance and promote healing. It is a controversial approach in some areas, such as age-related macular degeneration (AMD), where its efficacy and clinical relevance are still debated. However, the underlying principle remains consistent: to use specific light wavelengths to stimulate beneficial biological responses within the body. The non-invasive nature and generally low incidence of adverse events make PBM an appealing area for continued research and therapeutic development.

Does PBM Help with Chronic Pain?

Yes, PBM shows promise as a therapeutic alternative for managing chronic pain. A comprehensive systematic review, which included 14 studies, found that most trials reported significant pain reduction when PBM was used. This effect was particularly noted in conditions like fibromyalgia and neuropathy Systematic Review on Chronic Pain. Beyond just pain relief, some studies also observed improvements in functional abilities and overall quality of life for patients.

PBM's Role in Fibromyalgia Treatment

Fibromyalgia is a condition characterized by widespread chronic pain, fatigue, and other symptoms. PBM has been specifically investigated for its potential to alleviate this pain. In the systematic review of chronic pain, fibromyalgia was one of the key populations studied, and PBM demonstrated significant pain reduction in these patients. This finding aligns with earlier research, such as a single-blind, placebo-controlled trial published in 2002. This earlier study specifically evaluated the "Efficacy of low power laser therapy in fibromyalgia" and found it to be effective Efficacy of low power laser therapy in fibromyalgia: a single-blind, placebo-controlled trial. Another systematic review and meta-analysis on "Low-Level Laser Therapy for Fibromyalgia" also supports these findings, indicating its potential benefit Low-Level Laser Therapy for Fibromyalgia: A Systematic Review and Meta-Analysis. The consistent reports of pain reduction suggest that PBM could be a valuable addition to treatment plans for individuals suffering from fibromyalgia.

PBM for Neuropathic and Musculoskeletal Pain

Beyond fibromyalgia, PBM has also shown positive results for other types of chronic pain, including peripheral neuropathies and musculoskeletal pain. Peripheral neuropathies involve damage to nerves outside the brain and spinal cord, often leading to pain, numbness, and weakness. The systematic review on chronic pain included populations with peripheral neuropathies and found that PBM led to significant pain reduction in these cases. Similarly, for musculoskeletal pain, which affects muscles, bones, ligaments, tendons, and nerves, PBM also demonstrated benefits. The mechanism is believed to involve the modulation of inflammatory processes and the promotion of cellular repair, which can help to alleviate the underlying causes of pain. The ability of PBM to reduce pain in diverse chronic conditions highlights its broad therapeutic potential.

Impact on Functional Gains and Quality of Life

The benefits of PBM for chronic pain extend beyond just reducing pain intensity. Several studies included in the systematic review observed functional gains in patients. This means individuals were able to perform daily activities with greater ease and experience less limitation due to their pain. Improved function is a critical outcome for chronic pain sufferers, as it directly impacts their independence and overall well-being. Additionally, some studies reported an improved quality of life. This encompasses a range of factors, including better sleep, reduced emotional distress, and a greater ability to participate in social activities. The comprehensive nature of these improvements suggests that PBM addresses not only the physical sensation of pain but also its broader impact on a person's life. The low incidence of adverse events associated with PBM further supports its use as a safe option for long-term pain management.

Study Parameters and Heterogeneity

While the evidence for PBM in chronic pain is promising, it is important to acknowledge the diversity in study protocols. The systematic review on chronic pain, which encompassed studies published between September 2015 and September 2025, noted that the "heterogeneity of technical parameters compromises the standardization of results." This means that different studies used varying wavelengths, power outputs, treatment durations, and application methods. Such variations can make it challenging to directly compare results and establish a single, optimal PBM protocol for all chronic pain conditions. Despite this heterogeneity, the consistent finding of significant pain reduction across most trials reinforces the overall efficacy and safety of the method. Future research will likely focus on standardizing these parameters to maximize therapeutic benefits and clarify best practices for specific chronic pain populations.

Can Whole-Body PBM Improve Exercise Performance or Recovery?

Whole-body PBM has been investigated for its potential to improve exercise performance and recovery, but current evidence suggests it primarily benefits sleep quality, not direct physical performance or fatigue biomarkers. A systematic review identified five studies that looked at whole-body PBM in physically active participants. While two of these studies reported better sleep, none showed any advantage for exercise performance or recovery biomarkers Whole-Body PBM for Exercise Performance.

Review of Whole-Body PBM Studies

Our analysis included a systematic review that specifically focused on "whole-body photobiomodulation for exercise performance and recovery." This review searched multiple databases, including PubMed, The Cochrane Library, EBSCO, and Google Scholar, to find relevant studies. It ultimately identified five studies that met its criteria, all involving human participants. These studies used whole-body PBM in the red or near-infrared spectrum, applying it either before or after exercise. The total number of participants across these five studies was 105, representing both sexes and engaging in different types of exercise. The purpose of the review was to evaluate if this type of PBM could enhance performance or aid in recovery.

Impact on Sleep Quality

Interestingly, while direct exercise benefits were not observed, whole-body PBM did show a positive effect on sleep quality. Two out of the five identified studies reported improvements in sleep. These improvements were determined through both subjective questionnaires, where participants reported feeling better rested, and objective measures from commercial sleep trackers. The physiological markers also supported these findings. Participants using whole-body PBM showed higher serum melatonin levels, which is a hormone crucial for regulating sleep-wake cycles. They also had a lower nocturnal heart rate, indicating a more relaxed state during sleep. This suggests that whole-body PBM might contribute to better overall recovery by optimizing sleep, even if it doesn't directly impact muscle fatigue or performance metrics during waking hours.

No Evidence for Exercise Performance or Fatigue Biomarkers

Despite the promising findings related to sleep, the systematic review concluded that none of the five studies demonstrated any benefit of whole-body PBM on biomarkers of fatigue or exercise performance. This means that while participants might have slept better, their physical output during exercise, or their physiological markers of muscle fatigue (such as lactate levels or markers of muscle damage), did not show significant improvement. This contrasts with some of the reported benefits of localized PBM, which has been studied as a method to improve exercise performance and recovery in specific areas of the body. The lack of effect from whole-body PBM on these direct performance and recovery metrics suggests that the diffuse nature of the light application, or perhaps the specific protocols used, may not be sufficient to elicit the same localized physiological responses that contribute to enhanced physical exertion or faster muscle repair.

Discrepancies with Localized PBM Benefits

The findings for whole-body PBM create a discrepancy when compared to the established effects of localized PBM. Localized PBM involves irradiating a specific muscle group or area of the body. Studies on localized PBM have often reported positive outcomes for improving exercise performance and recovery, such as reduced muscle soreness, faster recovery of muscle function, and even increased strength or endurance. The systematic review on whole-body PBM acknowledged this difference and highlighted the need for further research to understand why whole-body application does not yield the same exercise-related benefits as localized treatment. It is possible that the dosage, penetration depth, or specific cellular targets differ significantly between localized and whole-body approaches, leading to varied outcomes. Resolving these discrepancies is crucial for understanding the optimal application of PBM in sports and exercise science.

Is PBM Effective for Age-Related Macular Degeneration (AMD)?

PBM is considered a controversial approach for managing dry age-related macular degeneration (AMD). While it aims to halt or reverse the progression of vision loss by modulating mitochondrial activity, its overall efficacy and clinical relevance are still under debate. A systematic review and meta-analysis of randomized controlled trials specifically sought to assess these aspects.

PBM as a Treatment for Dry AMD

Age-related macular degeneration (AMD) is a leading cause of vision loss, particularly affecting older adults. Dry AMD, the more common form, involves the thinning of the macula, the central part of the retina responsible for sharp, detailed vision. PBM has been proposed as a potential management strategy for dry AMD. The theoretical basis for its use lies in its ability to influence mitochondrial activity. Mitochondria are crucial for cell energy production, and their dysfunction is believed to play a role in the pathogenesis of AMD. By modulating mitochondrial function, PBM aims to improve the health of retinal cells, potentially slowing down or even reversing the degenerative processes that lead to vision loss. This approach positions PBM as a non-invasive intervention that could offer a new avenue for treatment where options are currently limited.

Systematic Review and Meta-Analysis Findings

To assess the effectiveness of PBM for AMD, a systematic review and meta-analysis of randomized controlled trials (RCTs) was conducted. This rigorous type of study design compares PBM against a sham treatment in patients with dry AMD. The researchers systematically searched major medical databases, including PubMed, Embase, and Cochrane databases, to identify relevant trials. The goal was to provide a comprehensive overview of the available evidence. They performed trial sequential analysis (TSA) and minimal clinically important difference (MCID) calculations. These methods help determine both the statistical significance and the practical, real-world importance of any observed effects. The analysis aimed to provide clarity on whether PBM truly offers a meaningful benefit for AMD patients.

Debated Efficacy and Clinical Relevance

Despite the theoretical promise and the rigorous review process, the efficacy and clinical relevance of PBM as a potential approach for managing dry AMD remain debated. The systematic review highlighted this ongoing controversy. While the intention is to halt or reverse progression through mitochondrial activity modulation, the evidence gathered did not definitively settle the question of its widespread effectiveness. This could be due to several factors, including the heterogeneity of study protocols, variations in patient populations, or the inherent complexity of AMD itself. The debate means that while some individual studies might show positive trends, the overall body of evidence, especially when subjected to meta-analysis, may not yet be strong enough to establish PBM as a universally recommended treatment for AMD. Further research, potentially with larger and more standardized trials, will be needed to conclusively determine PBM's place in AMD management.

The Importance of Mitochondrial Activity Modulation

The concept of modulating mitochondrial activity is central to the proposed benefits of PBM for AMD. Mitochondria are often referred to as the "powerhouses" of the cell because they generate most of the adenosine triphosphate (ATP), which is used as a source of chemical energy. In degenerative diseases like AMD, mitochondrial dysfunction can lead to cellular stress, inflammation, and ultimately cell death in the retina. PBM, by stimulating cytochrome c oxidase within the mitochondria, is thought to improve energy production, reduce oxidative stress, and activate protective pathways. These cellular responses are hypothesized to safeguard retinal cells, particularly photoreceptors and retinal pigment epithelial cells, from damage. If PBM can effectively enhance mitochondrial function in the macula, it could theoretically slow the progression of vision loss or even promote some degree of recovery. However, translating this cellular mechanism into consistent and clinically significant improvements in human vision for AMD patients is the challenge that continues to fuel the debate.

What is the Safety Profile of PBM?

The safety profile of PBM appears to be favorable, with a low incidence of adverse events reported in studies. This reinforces the method's safety, particularly in the context of chronic pain management. However, the varying technical parameters used across different studies can make it difficult to standardize and compare results consistently.

Low Incidence of Adverse Events

One of the most appealing aspects of PBM as a therapeutic option is its generally low risk. In a systematic review that included 14 studies on chronic pain, the "incidence of adverse events was low." This finding applies to various conditions, including fibromyalgia, peripheral neuropathies, orofacial pain, and musculoskeletal pain. Low-level laser therapy, which is a form of PBM, has been evaluated for safety in numerous clinical trials. The fact that serious side effects are rare is a significant advantage, especially for treatments that may be used over extended periods or for chronic conditions. Patients can undergo PBM sessions with relatively little concern about negative reactions, which contributes to its growing acceptance and exploration as a non-pharmacological intervention. This safety record makes PBM a particularly attractive option for individuals who may be sensitive to medications or prefer non-invasive treatments.

Reinforcement of Method's Safety

The consistent reporting of a low adverse event rate across different PBM applications strongly reinforces the method's safety. For instance, in studies looking at PBM for chronic pain, the observation that adverse events were infrequent provides a strong argument for its use. This safety profile is a key reason why PBM is considered a promising therapeutic alternative, particularly for conditions where long-term management is required and minimizing side effects is paramount. The non-invasive nature of PBM, which involves applying light to the skin without breaking it, inherently reduces risks associated with more invasive procedures. The energy levels used in PBM are typically low, designed to stimulate cellular processes rather than cause thermal damage, further contributing to its safety. This aspect is crucial for patient acceptance and for healthcare providers considering PBM as a viable treatment option.

Heterogeneity of Technical Parameters

Despite the strong safety profile, a challenge in PBM research is the "heterogeneity of technical parameters," which "compromises the standardization of results." This means that studies often use different types of PBM devices, varying wavelengths of light (e.g., specific red or near-infrared ranges), different power outputs, varying treatment durations, and different frequencies of application. For example, one study might use a 660 nm red light laser at 100 mW for 5 minutes, while another might use an 810 nm near-infrared LED array at 50 mW for 15 minutes. Such variations make it difficult to establish a single, universally optimal PBM protocol for a given condition. It also complicates meta-analyses and systematic reviews, as combining data from vastly different protocols can mask or dilute true effects. While the overall safety of PBM is clear, the lack of standardization can make it harder for practitioners to replicate results from research studies and for patients to know they are receiving the most effective treatment. Future research efforts are likely to focus on identifying and standardizing the most effective parameters for specific conditions to improve consistency and efficacy.

Safety in Whole-Body Applications

The safety of PBM also extends to whole-body applications. For instance, in the systematic review on whole-body PBM for exercise performance and recovery, no adverse events were reported among the 105 physically active participants across five studies. This suggests that even when larger areas of the body are exposed to PBM light, the treatment remains safe. The doses used in whole-body PBM are designed to be therapeutic without causing harm, similar to localized applications. The primary observed benefit in whole-body PBM was improved sleep quality, with no reported negative side effects related to this outcome. This broad safety profile, whether applied locally or across the entire body, makes PBM a low-risk option for a variety of health goals, from pain management to general wellness improvements like better sleep.

How Does Localized PBM Compare to Whole-Body PBM?

Localized PBM and whole-body PBM differ significantly in their reported benefits, particularly concerning exercise performance and recovery. While localized PBM has shown promise as a method to improve these aspects, whole-body PBM has not demonstrated similar advantages. This suggests that the way light is applied and the specific area targeted play a crucial role in the therapeutic outcomes.

Distinct Applications and Goals

Localized PBM involves directing red and near-infrared light to a specific, smaller area of the body. This approach is often used to target particular muscles, joints, or areas of pain. For example, localized PBM has been studied extensively as a method to improve exercise performance and recovery for specific muscle groups. The goal here is often to reduce muscle soreness, accelerate tissue repair, or enhance strength and endurance in the treated area. The precision of localized application allows for higher energy delivery to the targeted tissue, potentially eliciting stronger biological responses. This method is frequently employed in physical therapy clinics and sports medicine settings to address specific injuries or to aid athletes in their training. The focused application allows for tailored treatments based on the exact needs of a patient or athlete.

Whole-body PBM, in contrast, involves exposing the entire body, or a large portion of it, to red and near-infrared light. This is typically done in specialized chambers or beds equipped with many LEDs. The goals for whole-body PBM tend to be more generalized, focusing on systemic effects rather than localized tissue responses. While localized PBM might target a sore knee, whole-body PBM aims for broader benefits like improved overall well-being, better sleep, or systemic anti-inflammatory effects. The systematic review on whole-body PBM for exercise performance and recovery highlighted this broad application, with participants engaging in various exercise modalities. The expectation is that by treating the entire body, multiple systems might benefit simultaneously, leading to a more holistic improvement in health.

Divergent Outcomes for Exercise Performance and Recovery

When comparing the two approaches for exercise-related benefits, a clear divergence emerges. Localized PBM has a history of studies suggesting its efficacy in improving exercise performance and recovery. For instance, applying red light directly to a muscle group before or after strenuous activity has been linked to reduced muscle fatigue, faster recovery of muscle function, and decreased post-exercise soreness. These benefits are often attributed to the localized increase in ATP production, improved blood flow, and reduction in oxidative stress within the treated muscles.

However, whole-body PBM, despite its widespread application, has not shown similar benefits for exercise performance or recovery. The systematic review of five studies on whole-body PBM concluded that "none of the five studies reported any benefit of whole-body PBM on biomarkers of fatigue and exercise performance." This means that while localized treatment might help a specific muscle recover, exposing the entire body to light did not translate into measurable improvements in overall athletic output or physiological markers of fatigue. This difference in outcomes is a key point of discussion for researchers and practitioners.

Explaining the Discrepancies

The reasons behind these discrepancies are still being explored, but several factors might contribute. One possibility is the difference in light dosage and penetration depth. Localized PBM devices can often deliver a higher, more concentrated dose of light to a specific tissue depth, which might be necessary to trigger the desired cellular responses for muscle recovery or performance enhancement. Whole-body PBM, by spreading the light over a much larger surface area, might deliver a lower effective dose to any single tissue, potentially diluting its impact on specific performance-related pathways.

Another factor could be the specific cellular targets. Localized PBM might be more effective at directly stimulating muscle cells and their mitochondria, leading to localized benefits. Whole-body PBM, while potentially stimulating a broader range of cells, might not achieve the necessary threshold in muscle tissue to significantly impact acute exercise performance or recovery biomarkers. The systematic review on whole-body PBM explicitly stated that "further research is necessary to resolve discrepancies with the benefits observed in localized PBM studies." This ongoing need for investigation underscores the complexity of PBM and the importance of tailoring the application method to the specific therapeutic goal. Understanding these differences is crucial for optimizing PBM protocols and ensuring that patients and athletes receive the most effective treatment for their needs.

Frequently Asked Questions

What is photobiomodulation (PBM)?

Photobiomodulation (PBM) is a non-invasive therapeutic procedure that uses red and near-infrared light, typically from lasers or light-emitting diodes (LEDs). This light is applied to a local area of the skin to modulate mitochondrial activity and other cellular processes. The goal is to stimulate beneficial biological responses, such as reducing pain or promoting healing, without breaking the skin.

Does PBM help with chronic pain conditions like fibromyalgia?

Yes, PBM shows significant promise for chronic pain conditions. A systematic review, which included 14 studies, found that most trials demonstrated significant pain reduction with PBM, especially in conditions like fibromyalgia and neuropathy. Some studies also observed functional gains and improved quality of life for patients.

Can whole-body PBM improve athletic performance or recovery?

Whole-body PBM may improve sleep quality, but it has not shown direct benefits for exercise performance or recovery biomarkers. A systematic review of five studies with 105 physically active participants found that two studies reported better sleep quality, including higher serum melatonin and lower nocturnal heart rate. However, none of these five studies reported any positive effect on biomarkers of fatigue or exercise performance.

Is PBM considered safe?

Yes, PBM is generally considered safe. In studies on chronic pain, the incidence of adverse events with PBM was low, reinforcing the method's safety. This low risk applies to both localized and whole-body applications, making it an attractive non-invasive treatment option.

What is the difference between localized and whole-body PBM in terms of reported benefits?

Localized PBM has been studied as a method to improve exercise performance and recovery in specific areas of the body, often showing positive results. In contrast, whole-body PBM has shown no evidence of benefits for exercise recovery or performance in the five studies reviewed, though it may improve sleep quality. Further research is necessary to understand these discrepancies.