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Red Light Therapy and Parkinson’s Disease:

Exploring a Promising Approach

We aren’t making any claims in this article; we are simply sharing research.

Red light therapy is emerging as a promising tool for Parkinson’s disease. Learn how light influences brain health.

Emerging evidence suggests that light therapy may offer significant benefits in this area—which is encouraging, given that Parkinson’s disease is a challenging neurodegenerative condition with no known cure or way to reverse its progression.

Parkinson’s Disease: Overview, Causes, Symptoms, and Risk Factors

Let’s start by understanding what Parkinson’s disease actually is. We’ll be going through different reviews on the topic (1,2,3,4,5,6,7,8,9,10,11) to provide a well-rounded overview. While Parkinson’s is classified as a neurodegenerative brain disorder, there’s much more complexity to it—which we’ll explore later. For now, let’s take a look at how Parkinson’s presents from the outside:

Parkinson's Diagnosis

Parkinson’s disease begins with a diagnosis (1), typically made by a clinician based on observed symptoms. The diagnostic process includes reviewing your medical history, conducting physical and neurological examinations, and evaluating whether you meet the established criteria for Parkinson’s. Imaging tests like CT or MRI scans may be used to rule out other conditions.

Individuals may experience a mix of motor and non-motor symptoms—something that will become especially important as we explore further (12; 13). Let’s start with the motor symptoms, which primarily affect movement:

Tremors (shaking) at rest
Speech problems
Rigidity
Slow movement (bradykinesia)
Freezing of movement
Rigidity
Problems holding your posture
General fine motor problems, such as writing

There are also several non-motor symptoms to consider—many of which I’ll revisit when discussing red light therapy for Parkinson’s. That’s because effective treatment may need to target not just the brain, but other areas of the body as well.

Gut issues (hint!)
Poor sleep quality
Depression or anxiety
Loss of smell
Changes in cognition, such as your processing speed

These symptoms can vary widely from person to person, as there are different subtypes of Parkinson’s disease. A recent review highlights these subtypes as follows:

"Parkinson disease has multiple disease variants with different prognoses. Individuals with a diffuse malignant subtype (9%-16% of individuals with Parkinson disease) have prominent early motor and nonmotor symptoms, poor response to medication, and faster disease progression. Individuals with mild motor-predominant Parkinson disease (49%-53% of individuals with Parkinson disease) have mild symptoms, a good response to dopaminergic medications (eg, carbidopa-levodopa, dopamine agonists), and slower disease progression. Other individuals have an intermediate subtype. For all patients with Parkinson disease, treatment is symptomatic, focused on improvement in motor (eg, tremor, rigidity, bradykinesia) and nonmotor (eg, constipation, cognition, mood, sleep) signs and symptoms." (12).

Current medical treatment primarily focuses on managing motor symptoms, with non-motor symptoms addressed as a secondary concern. Unfortunately, these medications do not alter the progression of the disease (12).

Parkinson’s disease is more common in men than in women (13). Around age 60, approximately 2% of the population is affected, and that number increases to about 4% by age 80 (13). While early symptoms may prompt a physician to suspect Parkinson’s, a specialist typically confirms the diagnosis in most countries (1).

Now, let’s take a closer look at what’s happening in the brain—and throughout the body—that leads to the development of Parkinson’s disease:

Parkinson’s Disease: The Brain and Beyond

Let’s explore how Parkinson’s disease develops in the brain and other tissue (13; 14; 15). At the core of the neurodegenerative process in the brain is a region called the substantia nigra—which translates to “black substance.” This area contains neurons that are essential for producing dopamine, a key neurotransmitter involved in movement control.

Contrary to popular opinion, dopamine is not only involved with pleasure but, more accurately, motivation as stated in numerous writings (A,B).

Dopamine plays a vital role in both movement and higher-order cognitive functions such as abstract thinking and planning. In many ways, it underpins the advanced mental capabilities that define human cognition. Since dopamine also helps regulate motor control, it’s no surprise that Parkinson’s disease—where dopamine-producing neurons in the substantia nigra are damaged—leads to movement difficulties. But it doesn't stop there; cognitive issues and motivational challenges, including depression and anxiety, are also common symptoms.

In the Substantia Nigra, abnormal clumps of proteins known as “Lewy bodies” begin to accumulate, interfering with normal cellular function. Over time, this disruption impairs the brain’s dopamine system and ultimately leads to cell death—further worsening the condition.

As the disease progresses, it can begin to impact additional areas of the brain. When these regions become impaired, symptoms related to cognition, mood, and autonomic functions—such as digestion—often become more severe.

But the truth is, it’s a bit more complicated than that. Here’s how researchers describe it:

"Recent work has also highlighted maladaptive immune and inflammatory responses, possibly triggered in the gut, that accelerate the pathogenesis of Parkinson's disease." (13)

Gut health, immune response, and inflammation may all contribute to the development of Parkinson’s disease—a key point to keep in mind, as these systems can also be influenced by red light therapy.

Another key factor is the brain-gut axis—the communication pathway between the brain and the digestive system—in the context of Parkinson’s disease (4). Researchers have highlighted the importance of this connection as follows:

"However, recent research suggests a potential relationship between the commensal gut bacteria and the brain capable of influencing neurodevelopment, brain function and health. This bidirectional communication is often referred to as the microbiome-gut-brain axis. Accumulating evidence suggests that the onset of non-motor symptoms, such as gastrointestinal manifestations, often precede the onset of motor symptoms and disease diagnosis, lending support to the potential role that the microbiome-gut-brain axis might play in the underlying pathological mechanisms of Parkinson's disease." (4)

We’ll dive deeper into that shortly. For now, it’s worth noting that improving gut function through light therapy may help manage symptoms more effectively. And ideally, in the future, it could even play a role in preventing Parkinson’s or significantly slowing its progression.

So, what can be done to help prevent Parkinson’s disease? Let’s take a closer look:

Parkinson's Disease Risk Factors

So, how can you lower your risk of developing Parkinson’s disease? While genetics do contribute, they account for only about 35% of cases (15). The good news is that we have a wealth of review studies examining this topic (16; 17; 18; 19; 20). Here are some of the most significant findings so far:

"Modifiable lifestyle factors such as physical activity and tea and coffee drinking may reduce the risk of PD" (16).

Staying active and exercising regularly can go a long way in protecting against Parkinson’s disease.

Pesticide exposure is also considered a potential risk factor for Parkinson’s disease (17). Interestingly, smoking appears to have a protective effect—likely due to nicotine’s strong influence on dopamine activity, though the relationship is more complex than it seems (17). A similar protective trend has been observed with coffee consumption.

There are also several additional risk factors worth considering:

"Potential risk factors include traumatic brain injury, [...] organic solvent exposure, lead exposure, air pollution, Type 2 Diabetes, some dairy products, cardiovascular disease, and some infections including Hepatitis C, H. pylori, and COVID-19" (18).

Even diet can play a powerful preventive role—particularly dietary patterns like the Mediterranean diet or others designed to support brain health and reduce neurodegeneration (19).

In the end, genetics account for roughly 35% of the risk for developing Parkinson’s disease, while the remaining 65% is likely tied to environmental factors such as lifestyle choices, toxin exposure, and more. It’s also very likely that many contributing risk factors have yet to be fully identified.

What Happens as Parkinson’s Advances

As you might expect, Parkinson’s disease has a significant impact on quality of life (2). That’s no surprise, considering dopamine plays a crucial role in mood regulation and motivation—and this disease causes mood changes.

In the later stages, symptoms often become more severe and disabling (3). The risk of falls increases, cognitive decline may worsen, and digestive issues can become more pronounced. Additionally, mood-related symptoms like depression may intensify, sometimes requiring additional medications—which can bring their own side effects (6).

In many developing countries, access to quality treatment remains limited, even though Parkinson’s disease is just as prevalent (5).

So what can be done? Let’s explore the most effective treatment options available:

What Treatments Exist—and Where They Fall Short

Currently, the primary treatment for Parkinson’s disease involves medications that enhance dopamine activity—most notably L-Dopa (8). A variety of additional medications are also used, but these are focused solely on managing symptoms (8).

The good news is that new therapeutic strategies are actively being researched and developed (7; 21). These include novel drug therapies, brain stimulation techniques, immunotherapy, and more (22; 23).

Some studies are shifting away from purely pharmacological approaches and instead exploring the connection between Parkinson’s disease and mitochondrial health. Often referred to as the "powerhouses" of the cell, mitochondria are responsible for producing cellular energy. However, mitochondrial function naturally declines with age—unless supported by a healthy lifestyle—and this decline has been linked to a variety of health conditions over time.

Recent research has identified poor mitochondrial function as a contributing factor in Parkinson’s disease, highlighting it as a potential target for intervention (24; 25; 26; 27). Similarly, oxidative stress and chronic inflammation—both closely tied to mitochondrial health—appear to play significant roles(24; 25; 26; 27). Disruptions in cellular repair and recycling processes, such as autophagy and mitophagy (the specific recycling of mitochondria), are also likely involved.

The good news? Red light therapy has a powerful influence on all of these areas. The challenge? We’re still uncovering exactly how it works. This uncertainty is also part of why exercise may be such a strong preventive tool for Parkinson’s—it’s closely tied to healthy mitochondrial function (9; 10; 11).

Now that we’ve covered mitochondria, let’s dive into the role light therapy plays in supporting them:

How Red Light Therapy May Support Brain Health

There are approximately 600 studies exploring red light therapy's effects on the brain (28). Let’s focus on the core takeaways—specifically how red light therapy may support overall brain health, enhance cognitive function, and help reduce the risk of neurodegenerative diseases.

Various wavelengths of light—particularly in the near-infrared range (generally between 810 and 1,070 nm)—have shown promising effects on brain health. These wavelengths may help enhance cognitive function, improve mood, and support the treatment of neurological conditions such as Alzheimer’s, Parkinson’s, traumatic brain injuries, depression, and anxiety (as the research shows).

Brain, Alzheimer's Disease - 808 & 810nm - (65, 800-820, neutral, human RCT), (66, 810, positive, human), (67, 808 vs 1064 vs 808+1064, positive, in vitro), (68, 808, positive, in vitro), (69, 808, positive, animal), (70, 810, positive, human), (71, 630+680+810, positive, animal), (72, 630+810, positive, human), (73, 810, positive human RCT), (74, 810, positive, human), (74, 808, positive, animal), (75, 808, positive, animal), (76, 808, positive, animal).

Brain, Cognitive performance - 1064nm - (17, 852 vs 1064, human RCT, positive), (18, 1064, human RCT, positive), (19, 1064, animal, neutral), (20, 1064, human, positive), (21, 1064, human, positive), (22, 1064, human, positive), (23, 1064, human RCT, positive), (24, 1064, human RCT, positive), (25, 1064, human RCT, positive).

Brain, Depression - 808 & 810nm - (100, 810, positive, animal), (101, 810, positive, animal), (102, 810+830, positive, human), (103, 810+980, positive, human), (104, 808, positive, animal), (105, 630 vs 810, positive, animal), (106, 810, positive, animal), (108, 810, positive, human RCT).

Brain, EEG - 1064nm - (27, 1064, human RCT, positive), (28, 1064, human RCT, positive), (29, 1064, human RCT, positive), (30, 1064, human RCT, positive), (31, 1064, human, positive).

Brain, Functional connectivity - 1064nm - (32, 1064, human RCT, positive), (33, 1064, human RCT, positive), (34, 1064, human RCT, positive).

Brain, Injury - 808 & 810nm - (80, 810, positive, human RCT), (81, 808, animal, positive), (82, 808, positive, animal), (83, 810, positive, animal), (84, 810, positive, animal), (85, 810+980 vs 810, positive, human), (86, 810+980, positive, human), (87, 810, positive, animal), (88, 810, positive, animal), (89, 808, positive, animal), (90, 810, positive, animal), (91, 808, positive, animal).

Brain, Injury - 850nm - (14, 810 vs 850 vs 870, positive, human), (15, 629+850, positive, human), (16, 850, positive, human).

Brain, Opioid Addiction - 808 & 810nm - (59, 810, positive, human RCT), (60, 810, positive, human RCT), (61, 810, positive, human RCT).

Brain, Stroke (Clinical) - 660nm - (39, 630+660+850, human, positive), (40, 660+808+980, human, positive), (41, 660+850, human, positive).

However, dosing for brain-related red light therapy is more complex—and so are the underlying mechanisms. It remains unclear whether the benefits come from the light penetrating through the skull to reach brain tissue directly, or from irradiating blood vessels in the scalp that then influence brain function.

The encouraging news is that researchers have identified a wide range of physiological changes in the brain following red light therapy. These include improved cerebral blood flow, reduced inflammation, enhanced brain metabolism, and better functional connectivity—reflected in more balanced EEG patterns.

Currently, higher power outputs and doses around 60 J/cm² appear to be most effective for general brain support, largely due to the barrier the skull presents. That said, dosing needs vary depending on the specific condition. There’s no one-size-fits-all protocol for every brain-related issue, so each approach must be tailored to the condition. That’s why we’ll need to take a closer look at the latest published research in this area:

Red Light Therapy For Parkinson's Disease Clinical Studies

To date, there are roughly 60 studies examining light therapy for Parkinson’s disease, many of which involve animal models (28). Focusing solely on the human studies, let’s begin by looking at the published data on red light therapy for Parkinson’s disease:

Human Studies:

Here are some the human studies on red light therapy benefits for Parkinson's:

Here’s a five-year follow-up study based on earlier research (29). In this study, 12 participants agreed to be re-evaluated after five years. The encouraging news: seven of them had continued using light therapy throughout that entire period. One individual was excluded from the final analysis due to a separate diagnosis. The results of this long-term follow-up were quite remarkable:

"For the remaining six participants, there was a significant improvement in walk speed, stride length, timed up-and-go tests, tests of dynamic balance, and cognition compared to baseline and nonsignificant improvements in all other measures, apart from MDS-UPDRS-III [which is a test for the severity of motor symptoms], which was unchanged and one measure of static balance (single leg stance, standing on the unaffected leg with eyes open) which declined. Five of six participants either improved or showed no decline in MDS-UPDRS-III score and most participants showed improvement or no decline in all other outcome measures. No adverse effects of the photobiomodulation therapy were reported." (29)

The results are truly impressive. While more long-term studies are needed to validate these findings, the potential impact of light therapy is clear. In the original study, wavelengths of 810 nm and 904 nm were used (30).

In this study, six participants received treatment initially, while the other six served as a control group—but later went on to receive the same therapy. The study spanned an extended period and included home-based treatment following the completion of in-clinic sessions. The protocol involved 810 nm light delivered via a Vielight intranasal device, along with 904 nm laser therapy applied to the abdomen and back of the neck. Here’s what the results showed after the first year:

" Many individual improvements were above the minimal clinically important difference, the threshold judged to be meaningful for participants. Individual improvements varied but many continued for up to one year with sustained home treatment." (30).

They also state:

"[Red light therapy] was shown to be a safe and potentially effective treatment for a range of clinical signs and symptoms of [Parkinson's Disease]. Improvements were maintained for as long as treatment continued, for up to one year in a neurodegenerative disease where decline is typically expected. Home treatment of [Parkinson's Disease] by the person themselves or with the help of a carer might be an effective therapy option. " (30).

Sounds amazing, because it is!

Another study administered 72 treatments over a 12-week period, using a combination of 635 nm red light and 810 nm infrared light through the SYMBYX device (31; 32). The control group received an identical device that emitted no light.

The light therapy led to a noticeable reduction in motor symptoms among participants with Parkinson’s disease. These symptoms typically include tremors, rigidity, slowness of movement, postural instability, and gait disturbances. Only mild side effects were reported.

Next is a case series involving the use of 904 nm light (35), with seven participants included. In this study, the 904 nm laser was applied to nine specific points on the abdomen and one point at the back of the neck. Participants received in-clinic laser treatments for 12 weeks, followed by an additional 33 weeks of home-based light therapy. It’s worth noting that the study took place during the COVID-19 pandemic, which introduced additional challenges to the treatment process. Here’s how the researchers described their findings:

"A number of clinical signs of [Parkinson's Disease] were shown to be improved by remote [red light therapy] treatment, including mobility, cognition, dynamic balance, spiral test, and sense of smell. Improvements were individual to the participant. Some improvements were lost for certain participants during at-home treatment, which coincided with a number of enforced coronavirus disease 2019 (COVID-19) pandemic lockdown periods." (35)

And yet again, these results did nothing but impress!

Another study using 904 nm light combined two application methods: intraoral (inside the mouth to target the brain) and transcranial (through the skull) approaches (36).

In another study using 904 nm light, researchers combined red light therapy with hydrogen water (37). The light was applied to the back of the neck at a lower power output of 6 mW/cm². Despite this, participants showed improvements on the Unified Parkinson’s Disease Rating Scale (UPDRS), with some experiencing immediate, noticeable effects within the first week and continued progress into the second. It’s important to note that these outcomes likely resulted from the combined effect of both therapies, not from one intervention alone.

Additionally, a red light therapy helmet study involving wavelengths of 660, 670, 810, and 850 nm included five participants (38). One of them also used a 660 nm intranasal device. Here’s what the study found:

"We found that 55% of the initial signs and symptoms of the six patients showed overall improvement, whereas 43% stayed the same and only 2% got worse. " (39).

Once again, the results are promising—particularly considering the study spanned an impressive 24 months. Parkinson’s disease appears to be a clear example of how long-term light therapy can yield increasingly positive outcomes over time.

In contrast, another study using 670 nm light at 60 mW/cm² and a total dose of 8 J/cm² reported no significant effects(40). You could surmise that this may be due to the relatively low power output and especially the insufficient total dose delivered.

Overall, the potential benefits of red light therapy for Parkinson’s disease are highly encouraging. While application methods vary—from helmets and intranasal devices to light applied at the back of the neck or abdomen—longer-term studies consistently suggest a slowing of disease progression or stabilization of current health status.

Now, let’s take a look at some of the most recent review articles on the subject:

Reviews

Here are a few of the most recently published review findings and a summary of key arguments in them:

The first review highlights that red light therapy may improve the clinical symptoms of Parkinson’s disease(42), with neuroprotective effects specifically noted. It references a small number of clinical trials that have reported benefits for both motor and non-motor symptoms.

The authors also offer several compelling insights—for example, some forms of Parkinson’s may actually originate in the gut (45). They also emphasize that the exact causes of the disease remain unclear, even referring to them as "largely unknown" in their own words (45). The review also discusses findings from animal studies, and here’s a summary of those outcomes:

In this section, the review highlights several effects observed in animal studies that have not yet been demonstrated in human trials (45), including:

Reduced oxidative stress, a harmful byproduct of energy production when present in excess
Decreased gliosis, a reactive process triggered by nervous system damage
Lower levels of systemic inflammation
Improved vascular integrity, with a reduction in leaky blood vessels
Additional effects, such as decreased α-synuclein toxicity, reduced numbers of Fos+ cells, and more

The review also clearly outlines a key challenge in treating Parkinson’s disease: effectively reaching the substantia nigra pars compacta—the region of the brain responsible for dopamine production.

"While the animal models and the limited clinical studies are promising, a major hurdle for the use of [red light therapy] to the target symptoms of Parkinson’s disease is the delivery of light to the appropriate area of the brain [...]. Neuronal death begins in the "Substantia Nigra pars Compacta". While transcranial penetration of [red light therapy] to the "Substantia Nigra pars Compacta" in rodents is not a problem, it becomes a major concern in humans and larger animals. Transcranial [red light therapy] needs to penetrate the human hair, skin, tissue, bone, dura, blood, meninges and [cerebrospinal fluid] to reach the neurons in the brain. The maximum depth of penetration transcranially is most probably in the order of 20 to 30 mm, with progressively fewer photons with increasing depth. [red light therapy] light reaching the "Substantia Nigra pars Compacta" in humans where most damage is occurring is not physically possible. In an effort to overcome this problem, some studies have attempted to target the [red light therapy] towards the "Substantia Nigra pars Compacta" by placing the laser on the palate, using intranasal devices or by placing the LED on the mid-line of the neck, pointed toward the midbrain." (45)

Interestingly, some researchers have experimented with implanting light sources deep within the brain—a highly experimental approach aimed at directly targeting regions like the substantia nigra pars compacta (45). In theory, this could make it possible to reach areas otherwise inaccessible with non-invasive methods.

The second review primarily focuses on vascular parkinsonism and provides limited discussion on red light therapy (43), as it takes a broader look at emerging interventions for Parkinson’s disease. The third review follows a similar pattern, though it does speak favorably about red light therapy(44). Overall, these remaining reviews offer limited relevance to the specific focus of this analysis.

So, Can Red Light Therapy Really Help with Parkinson’s?

The answer appears to be a promising “yes.” Recent human studies are encouraging, with many showing that both motor and non-motor symptoms tend to stabilize—rather than worsen over time, as is typical in Parkinson’s disease. That alone is a significant achievement.

As with most complex health conditions, the most effective approach is likely a combination of therapies. Light therapy can play a powerful role, but it works best when integrated into a broader lifestyle strategy. Combining light therapy along with proper nutrition, quality sleep, regular sunlight exposure, and minimizing nighttime exposure to bright blue and green light can potentially make all the difference. All of these factors contribute to a more holistic path to better health.

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