A Complete Guide to Red Light Therapy

​​

What is Red Light Therapy? 

The human body is highly responsive to light. Red light therapy refers to low-level visible light and near-infrared (NIR) light photons in the red spectrum. These are absorbed through the skin to stimulate positive biological processes in the body.   

Hundreds of studies show that red wavelengths from 620-650 nanometers (nm) and NIR wavelengths from 810-850 nm fall into a ‘therapeutic window,’ with significant benefits and no known side effects.

 

The Many Names of Red Light Therapy

Red light therapy is called by many names. Let’s look into why that is, and the difference between some of the most-used terms. 

Infrared Therapy

Infrared therapy can refer to near-infrared or far-infrared treatment. Infrared saunas feature far-infrared wavelengths. 

It’s different from red light therapy in that wavelengths over 1000 nm heat up water molecules in the cells, stimulating the production of “heat shock proteins” as part of the healing process. NIR light affects the body much like red light, which doesn’t generate heat.

LED Light Therapy

LED light therapy refers to light treatment using LED devices as opposed to lasers. LEDs are very safe since they generate very little heat and there’s no danger of burns. Medical-grade LED devices can deliver professional results in the comfort of the home, which is convenient and cost-effective when treating chronic conditions or large areas of the body.

Low-Level Light Therapy

Low-level light therapy or low-level laser therapy (LLLT) refers to laser intensity that won’t harm the tissue when used properly. It is also called “cold” laser therapy. High-powered lasers are used surgically to kill certain cells or remove tissue but cold lasers are used in dermatology clinics to improve skin complexion and reduce signs of aging. Both LEDs and lasers are effective at delivering red/NIR light. 

Older studies used lasers, which offer a more concentrated beam of light with very slightly greater tissue penetration. However, LED devices offer a greater treatment area, which makes them more practical for widespread conditions. Many contemporary studies now use LEDs, which means that results can be reproduced at home using a powerful medical-grade device.

Near-Infrared Light Therapy

Near-infrared light therapy uses wavelengths from 810-850 nm, which absorb deeper into the body than red wavelengths. NIR light therapy is useful in treating systemic inflammation, nerve damage, deep muscle repair, joint pain, low back pain, and even the brain. Red light is used to regrow hair, and treat signs of aging, acne, and chronic skin disorders.

Photobiomodulation

Photobiomodulation refers to forms of light used therapeutically that utilize non-ionizing forms of light sources including lasers, LEDs, and broadband light, in the visible and infrared spectrum. This nonthermal process elicits photophysical and photochemical events at various biological scales. All wavelengths of light affect the body in unique ways, and all are beneficial to some degree. Knowing the pros and cons of each wavelength helps us use the right wavelength for the right purpose.    

 

How Does Red Light Therapy Work?

Visible red wavelengths treat each layer of skin tissue, while NIR wavelengths penetrate significantly deeper into the skin.  

This puts many health issues such as arthritic joints, overtrained muscles, and inflammatory skin conditions well within the reach of red light therapy treatment.

 

Increased Cellular Energy Production

Supporting optimal cellular performance is one key to healing. Trillions of cells in the body have specialized functions, but certain factors interfere with their performance. 

Tiny organelles called mitochondria inside each cell produce energy by converting glucose into adenosine triphosphate (ATP), which is the primary cellular fuel. When the mitochondria can’t produce enough ATP, the cell can't repair itself efficiently, defend itself against pathogens, or perform its functions adequately.

This is called mitochondrial dysfunction and it is believed to be at the core of most major diseases. You can see it in rapidly aging skin, autoimmune disorders, and other diseases.

As red and NIR light photons absorb into the skin, they come into contact with light-sensitive molecules called chromophores. This excites the mitochondria and stimulates the production of ATP. When cells produce more energy, they shift from self-preservation to function. 

When all cells in a treatment area are ‘refreshed,’ their renewed vitality quickly manifests as better health.

 

Hormesis

The following major mechanisms of action work together to support healing in a process called hormesis. 

The term hormesis refers to a dose–response relationship in which a low dose of a stressful stimulus activates an adaptive response that increases the resistance of the cell or organism. 

In the context of red light therapy, the increasing stimulus comes from the irradiance level. At the right dose, this effectively stimulates healing. 

Exercise is an example of hormesis. In moderation, exercise is beneficial. Exercise temporarily increases free radicals in the muscles as they break down under effort, stimulating a healing response that results in stronger, larger muscles. Going too hard too fast, though, can cause lasting muscle damage. 

Red light therapy activates many of the same biological effects as moderate exercise.

 

Reduced Inflammation

Chronic inflation is one of the main causes of mitochondrial dysfunction. Acute short-term inflammation is a temporary immune response to injury or infection and is a natural part of the healing process.

But if the inflammatory process continues even when no danger is present, inflammation begins damaging cells. Chronic inflammation is implicated in Alzheimer’s Disease, cancer, asthma, acne, heart disease, rheumatoid arthritis, and other conditions.

Red light therapy has a powerful anti-inflammatory effect. Some of the benefits of red light therapy could be due to the effect of red light on the gut biome (by application to the abdomen), where it reduces chronic inflammation and supports healthy gut bacteria that are vital to the immune response.

 

Improved Circulation

Good blood and lymph flow are essential for health and healing. Blood brings oxygen, nutrients, and immune cells to damaged areas. Lymph removes waste and toxins that impede cell function.

Red/NIR light acts as a vasodilator and has been used to treat vascular dysfunction in diabetic patients and increase blood circulation in diabetics with chronic leg wounds.

Red light therapy also stimulates production of endothelial cells, which make up the walls of blood and lymph capillaries. 

 

Increased Collagen and Elastin Production

Collagen is most often associated with youthful skin (this protein makes up about 80% of the skin), but it is also present in muscles, joints, and connective tissue. Collagen production can be altered by aging, chronic inflammation, and other factors. 

Red light therapy stimulates collagen synthesis to help with anti-aging, wound healing, and joint pain. It may even reduce the progression of osteoarthritis by stimulating the production of Type 3 collagen found in cartilage. 

Red light therapy also stimulates elastin and hyaluronic acid production. Elastin is the protein that allows the skin to bounce back after being stretched. Hyaluronic acid also helps the skin stretch and supports skin wound healing.

In a study involving 113 participants, the red light therapy treatment group experienced significantly improved skin complexion along with smoother skin and intradermal collagen density increase.

 

Reduces Inflammatory Cytokines

In a 2013 paper, light therapy researcher Dr. Michael Hamblin stated that a single red light therapy treatment can reduce inflammatory cytokines as soon as 24 hours after treatment. 

Cytokines are proteins involved in the communication of pain signals; thus, reducing inflammatory cytokines could lead to a lessened perception of pain.

 

Stem Cell Activation

Red and NIR light therapy activates the production of stem cells in the bone marrow. These “master cells,” or non-specialized cells are present throughout the body in a dormant state. In response to an injury or infection, the bloodstream transports stem cells to the affected area. There, they develop into any type of cell that the body needs.

 

 

The Benefits of Red Light Therapy

Red light therapy supports true healing by addressing the root cause rather than simply treating symptoms. 

In this section, we’ll cover the most common uses for this safe and non-invasive therapy. You can find more in-depth info on the many applications for red light therapy in the Learning Center. 

 

Anti-Aging

Red light therapy has been clinically proven to reduce fine lines and wrinkles, sun damage, sagging skin, and to smooth out the complexion. You may see results in as little as three weeks of daily use. Ongoing maintenance can keep your skin looking young and vibrant.

 

Arthritis and Joint Health

Red light therapy can ease pain and restore mobility due to osteoarthritis, rheumatoid arthritis, sacroiliac joint disorders, and other joint problems.

Most arthritis is classified as osteoarthritis (OA), or degenerative arthritis due to overuse (not aging). A smaller percentage of people suffer from inflammatory arthritis including rheumatoid arthritis (RA) and psoriatic arthritis (PA). Whatever the type of arthritis, red light therapy can help restore mobility and relieve pain.

Red light therapy can complement conventional physical therapy and may postpone the need for joint replacement surgery. Patients in one study experienced increased thickness in their synovial and femoral cartilage after red light treatment. It can also significantly reduce arthritis pain, decrease in morning stiffness, and reduce inflammation.

 

Bone Health

Red light therapy can help speed up healing of bone fractures. It improves the formation of blood vessels and increases bone growth factors and increases mineralization for faster rebuilding of bone density after a fracture.  

 

Brain Health

NIR light can treat brain conditions. Transcranial light therapy shines NIR wavelengths onto the forehead. Transnasal light therapy involves shining light through the nasal cavity into the central areas of the brain.

Light therapy helps damaged neurons replenish and heal through mitochondrial stimulation, reduced inflammation, and increased circulation.

Numerous studies including this one show that transcranial red light therapy can improve cognitive function in dementia patients, assist in healing from traumatic brain injury (TBI) and stroke, ease psychiatric and mood disorders like anxiety and depression, slow or reverse age-related cognitive decline, and ease symptoms of neurodegenerative disorders like Alzheimer’s Disease and Parkinson’s Disease.

 

Age-Related Cognitive Decline Neurodegenerative Disorders

NIR light therapy is an exciting potential treatment for dementia, Alzheimer’s Disease (AD), and Parkinson’s Disease (PD).

Dementia, which includes AD, affects approximately 7 million American adults and that number is projected to rise as the Baby Boom generation ages. 

Patients with mild to moderately severe dementia received 12 weeks of treatment that included weekly in-clinic transcranial/transnasal treatment sessions and daily at-home intranasal light therapy. The second phase involved a no-treatment 4-week period. After 12 weeks, there was significant progress in memory recall, visual attention, task switching, executive brain function, and other cognitive performance markers. 

Patients also slept better, had fewer outbursts of anger and anxiety, and wandered less after treatment. Since the no-treatment period saw significant declines, the authors suggest that ongoing treatment could be vital for managing dementia and AD.

Parkinson’s Disease is characterized by a slow degeneration of neurons related to motor and non-motor function. One study that focused on age-related cognitive decline also noted reductions in tremors and improvements in balance in patients with PD-related dementia. 

Parkinson’s develops after the mass death of neurons in the midbrain. The authors say that NIR light therapy can stabilize dying neurons, potentially slowing disease progression. 

 

Traumatic Brain Injuries and Stroke

People with traumatic brain injury (TBI) or stroke may suffer from psychiatric disorders and cognitive impairments including mood swings, anxiety, depression, memory, and problems concentrating. 

NIR light therapy can reduce inflammation and oxidative stress, stimulate ATP production, initiate neurogenesis (formation of new neurons and glial cells) and initiate synaptogenesis (formation of communication channels called synapses between brain cells). 

This supports healing and restoration of damaged brain tissue and improvement in executive function, verbal learning, and other cognitive markers.

 

COVID-19 Complications Including Chronic Fatigue Syndrome

Red light therapy regulates the immune response in patients with COVID-19, which is especially good news for anyone suffering from “long COVID.”

Myalgic encephalomyelitis or chronic fatigue syndrome (CFS) is a complex multi-system disease currently considered incurable and may be a complication of COVID-19. 

An intriguing 2020 study suggests that using red light to stimulate the microbiome gut/lung axis can support healing from COVID-19-related chronic problems including CFS.  

Why does this matter? As ancient physician Hippocrates said, “All disease begins in the gut.” Today, we know he wasn’t wrong. 

The gut microbiome, or the beneficial bacterial environment in the digestive system, is an essential part of the immune system. Red light therapy helps treat systemic conditions by supporting the gut microbiota. This includes giving patients reduced susceptibility to COVID-19. 

Red light therapy applied to the chest may improve airway function, blood oxygenation, reduce immune overactivity to prevent chronic inflammation, and ease depression brought on by social isolation and anxiety about the future.

 

Fertility

Red light therapy can improve fertility in both men and women by boosting natural testosterone production in men and improving egg quality in women.

 

Fibromyalgia

Fibromyalgia pain and muscle weakness could be mitigated with red light therapy. The treatment targets the entire hierarchy of mechanisms relating to the origin and regulation of pain.

 

Hair Regrowth

Red light therapy promotes new hair growth in people with male and female pattern hair loss, also known as androgenetic alopecia. It works by stimulating the anagen and telogen phases in hair follicles and inhibiting the catagen (regression into dormancy) phase, thus keeping hair follicles in the growth phase longer. 

 

Hashimoto's Hypothyroidism

The thyroid regulates the metabolic processes of the body. Hypothyroidism results in a dramatic slowdown of body systems leading to fatigue, weight gain, depression, cognitive impairment, cold sensitivity, and muscle weakness. 

From 2006 to 2009, study participants with hypothyroidism were treated with 830 nm light and many were able to significantly reduce the use of levothyroxine, suggesting that red light therapy is effective at improving thyroid function.

Though studies are few, the promise is there since inflammation is the primary cause of autoimmune hypothyroidism and red light therapy has powerful anti-inflammatory properties.

Anti-inflammatory Response 

Chronic inflammation is considered to be the root cause of most diseases; reducing chronic inflammation is an important part of healing. Red light therapy has powerful anti-inflammatory effects. In addition to healing, the treatment could be used preventatively to remove inflammation and thus remove the cause of major health concerns.  

 

Immune Function

Acute inflammation is a beneficial function of the immune system but chronic inflammation inhibits the body’s ability to protect itself. Dr. Hamblin's 2017 paper discusses a temporary boost in inflammation to support healing; once the inflammatory response is no longer needed, red light inhibits inflammation. This ability to down-regulate the inflammatory process is important for joint disorders, injuries, and other health challenges.

 

Muscle Recovery

For weekend warriors and elite athletes alike, red light therapy can increase athletic performance, prevent delayed-onset muscle soreness (DOMS), and heal and regenerate damaged muscle tissue.  

Pre- and post-exercise red/NIR light therapy can increase athletic performance, reduce recovery time, increase muscle mass, and decrease inflammation. It has even been suggested that red light therapy could be an unfair competitive advantage!

 

Oral Health

Pain in the mouth can be distressing. Red light therapy can reduce dentin hypersensitivity and ease pain in temporomandibular disorder (TMJ).

 

Neuropathy and Nerve Health

A 2017 study concluded that nerve cells respond well to the bio-stimulating effects of NIR light therapy. First, the treatment reduces inflammation to give nerve cells a chance to heal and regenerate. Then, it promotes nerve regeneration which is necessary to restore nervous system function.

Red light therapy stimulates the production of Schwann cells, which form the protective myelin sheath around nerves. It also stimulates fibroblasts to produce collagen that supports normal nerve cell function. Together, Schwann cells and fibroblasts work together to form a “cord” that rejoins damaged nerve cells to healthy nerve cells.

 

Pain Relief

Whether your pain is acute from an injury or you have chronic pain in the back or knees, red light therapy has been shown effective in relieving many types of pain:

• Pinched nerves

• Frozen shoulder 

• Low back pain

• Ankylosing spondylitis 

• Degenerative knee osteoarthritis

 

Respiratory Health

Inflammation can cause a variety of respiratory complications. Red light therapy can reduce inflammation in patients with lung fibrosis, chronic obstructive pulmonary disease (COPD), and bronchial asthma and allergic rhinitis. 

 

Skin Health

Red light therapy is best known as a skin rejuvenating treatment. It also treats chronic inflammatory skin disorders including psoriasis, eczema, acne, and rosacea. Regular ongoing treatments can put skin disorders into remission.

Many studies confirm the beneficial effects of red and NIR light on the skin, including this landmark study.

 

Sleep

Good sleep is essential for cognitive functioning, emotional health, and physical health. In 2012, 20 elite female basketball players received 30 minutes of red light therapy every night for 14 days. The results included higher serum melatonin levels, better sleep, and better endurance performance.

 

Tendonitis and Other Sports Injuries

Red light therapy can treat bone breaks, sprains, torn muscles and other sports injuries.

Many professional sports teams use red light therapy as part of daily training to accelerate recovery and allow athletes to return to training quickly after injury.

University athletes with sprains, contusions, tendonitis, and ligament damage showed a faster return-to-play after treatment with 830 nm light. The treatment group was able to return to training in just under 10 days, compared with the 19-day average in the control group.

 

Weight Loss and Reduction of Cellulite

It may be surprising that red light therapy can help you lose weight, but several studies confirm that it can. 

20 obese women were asked to perform aerobic and resistance training; one group also received treatment with NIR light, which resulted in a greater reduction in visceral fat and reduced neck and waist circumference. Just as importantly, the treatment group developed higher leptin levels (the hunger-inhibiting hormone).

Red light therapy can cause fat cells to develop temporary perforations that allow them to release lipids: up to 80% of the lipids after just four minutes and more than 90% after 6 minutes. The released lipids convert into carbon dioxide and are naturally expelled from the body. 

 

Wound Healing  

Red light therapy can minimize downtime after surgery and accelerate healing in wounds in any stage. When applied immediately after injury or surgery, red light can lead to less scarring by ensuring that emerging cells grow into normal skin rather than scar tissue. 

 

A Very Brief History of Red Light Therapy

Light therapy, or “heliotherapy,” has been used for millennia by healers who understood the healing properties of sunlight.  

• In 1666, Sir Isaac Newton discovered that sunlight consists of many different wavelengths. In the late 1800s, individual wavelengths were first isolated using artificial light.

• Dr. Niels Ryberg Finsen first used artificial UV light therapeutically in 1893. He later received the Nobel Prize for his treatments of tuberculosis using UV light, and smallpox scars using red light. 

• Albert Einstein first explained the theory of stimulated emission in 1917, which became the basis of the invention of the laser. 

• The laser was developed 1962, and Hungarian physician Endre Mester’s low-level laser therapy device followed in 1967 to treat skin cancer and speed up wound healing.

• The first practical light emitting diodes (LEDs) were developed in 1962 by Nick Holonyak, Jr., offering an efficient alternative to incandescent bulbs. Like lasers, LEDs can produce a single wavelength of light.

• In the early 1990s, NASA researchers experimented with lights suitable for growing plants in space. Researchers tending the plants noticed that exposure to red LED light resulted in faster healing of hand wounds. This sparked interest in using red light to prevent muscle loss and slow healing that astronauts experience in zero gravity. Research into red light therapy began in earnest.

• In 2012, we researched and developed the industry’s 12-wave spectrum for horticultural use. The first high-powered LED panel followed in 2016. It featured one red wavelength and one NIR wavelength.

• Advances in LED technology in the last decade brought red light therapy into the mainstream, where previously getting treatment was limited to health professionals.

• Today, researchers have a deeper understanding of the mechanisms of action behind this natural treatment and more treatment applications are emerging.

PlatinumLED’s high-powered LED therapy light panels are leading the photobiomodulation industry– presenting the public and health practitioners accessibility to medical grade redlight therapy devices that promote the most powerful irradiance for the most optimal healing experience. 

Functional Medicine Doctor of Physical Therapy

Dr. Alayna Newton, PT, DPT, FAFS

 

The Side Effects of Red Light Therapy

To date, there have been no reports of serious adverse side effects of red light therapy. Individuals with highly sensitive skin could experience temporary redness and tightness, likely due to increased blood circulation to the treatment area. This could be avoided with shorter treatments.

Red light therapy is safe even for sensitive parts of the body including the eyes and the testes. In fact, red light therapy has been used to improve eye health and to boost testosterone. Although red light therapy can improve eye health, the intense light emitted from a powerful LED device can cause eye strain. Eye treatments should be kept to a maximum of three minutes and always under the guidance of an ophthalmologist. When not treating the eyes, wear light-blocking goggles.

The many studies that have been performed on red light therapy treated used treatment times ranging from 3 to 20 minutes. Within this range, the body’s biological response to red light is favorable. While no immediate adverse effects have been reported during treatments longer than 20 minutes, more is not better because the biological processes stimulated by light treatment can’t be rushed.