Complete Guide to Red Light Therapy

What is red light therapy?

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

Hundreds of studies show that red wavelengths of 620-650 nanometers (nm) and NIR wavelengths of 810-1060 nm fall within a "therapeutic window," with significant benefits and no known side effects.

The Many Names of Red Light Therapy

Red light therapy goes by many names. Let's explore why and the differences between some of the most commonly used terms.

Infrared therapy

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

It differs from red light therapy in that wavelengths above 1000 nm heat water molecules in cells, stimulating the production of "heat shock proteins" as part of the healing process. NIR light affects the body in much the same way as 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, as they generate very little heat and there is no risk of burns. Medical-grade LED devices can provide professional results in the comfort of your home, which is convenient and cost-effective when treating chronic conditions or large areas of the body.

Low-intensity light therapy

Low-level light therapy, or low-level laser therapy (LLLT), refers to laser intensity that does not harm tissue when used correctly. It is also called "cold" laser therapy. High-powered lasers are used surgically to kill specific cells or remove tissue, but cold lasers are used in dermatology clinics to improve skin appearance 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 slightly greater tissue penetration. However, LED devices offer a larger treatment area, making them more practical for widespread conditions. Many contemporary studies now use LEDs, meaning the results can be reproduced at home using a powerful, medical-grade device.

Near infrared light therapy

Near-infrared light therapy uses wavelengths of 810–850 nm, which are absorbed more deeply in 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 brain pain. Red light is used to regrow hair and treat signs of aging, acne, and chronic skin conditions.

Photobiomodulation

Photobiomodulation refers to therapeutically applied forms of light that utilize non-ionizing light sources, including lasers, LEDs, and broadband light in the visible and infrared spectrum. This non-thermal process triggers photophysical and photochemical events at various biological scales. All wavelengths of light affect the body in unique ways, and all are beneficial to some extent. 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 every layer of skin tissue, while NIR wavelengths penetrate significantly deeper into the skin.

This puts many health problems, such as arthritic joints, overused muscles, and inflammatory skin conditions, within reach of red light therapy treatment.

Increased cellular energy production

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

Tiny organelles called mitochondria within each cell produce energy by converting glucose into adenosine triphosphate (ATP), which is the cell's primary fuel. When mitochondria fail to produce enough ATP, the cell cannot repair itself efficiently, defend itself against pathogens, or perform its functions properly.

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

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

When all the cells in a treatment area are "renewed," their renewed vitality quickly manifests in better health.

Hormesis

The following main mechanisms of action work together to aid 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 level of irradiation. 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 muscles as they break down under exertion, stimulating a healing response that results in larger, stronger muscles. Going too fast and hard, however, can cause lasting muscle damage.

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

Reduced inflammation

Chronic inflammation is a major cause of mitochondrial dysfunction. Short-term acute 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 there is no present danger, the inflammation begins to damage 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 may be due to its effect on the gut biome (through application to the abdomen), where it reduces chronic inflammation and supports healthy gut bacteria, which are vital for immune response.

Improved circulation

Good blood and lymph flow is essential for health and healing. Blood brings oxygen, nutrients, and immune cells to damaged areas. Lymph removes waste and toxins that impede cellular 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 the production of endothelial cells , which make up the walls of blood and lymphatic capillaries.

Increased collagen and elastin production

Collagen is most often associated with youthful skin (this protein makes up about 80% of skin), but it's 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 can even reduce the progression of osteoarthritis by stimulating the production of Type 3 collagen, found in cartilage.

Red light therapy also stimulates the production of elastin and hyaluronic acid . Elastin is the protein that allows skin to recover after being stretched. Hyaluronic acid also helps the skin stretch and aids in wound healing.

In a study involving 113 participants, the red light therapy treatment group experienced significant improvement in skin appearance, as well as smoother skin and increased intradermal collagen density.

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 for up to 24 hours after treatment.

Cytokines are proteins involved in communicating pain signals; therefore, reducing inflammatory cytokines may lead to reduced pain perception.

Stem cell activation

Red and NIR light therapy activates the production of stem cells in the bone marrow. These "master cells," or unspecialized cells, are present throughout the body in a dormant state. In response to injury or infection, the bloodstream transports stem cells to the affected area. There, they develop into whatever cell type the body needs.

The benefits of red light therapy

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

In this section, we'll cover the most common uses for this safe, non-invasive therapy. You can find more in-depth information on the many applications of red light therapy in the Articles and Science Center .

Anti-aging

Red light therapy has been clinically proven to reduce fine lines and wrinkles , reduce sun damage, and smooth skin. You can see results in just three weeks of daily use. Continued maintenance can keep your skin looking youthful and vibrant.

Arthritis and joint health

Red light therapy can relieve pain and restore mobility caused by 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 (PsA). Regardless of the type of arthritis, red light therapy can help restore mobility and relieve pain .

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

Bone health

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

Brain Health

NIR light can treat brain conditions. Transcranial light therapy projects NIR wavelengths onto the forehead. Transnasal light therapy involves projecting light through the nasal cavity to the central areas of the brain.

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

Several studies, including this one, show that transcranial red light therapy can improve cognitive function in patients with dementia, aid in the healing of traumatic brain injury (TBI) and stroke, alleviate psychiatric and mood disorders such as anxiety and depression, slow or reverse age-related cognitive decline, and alleviate symptoms of neurodegenerative disorders such as Alzheimer's disease and Parkinson's disease.

Age-related cognitive decline Neurodegenerative disorders

NIR light therapy is a promising potential treatment for dementia, Alzheimer's disease (AD), and Parkinson's disease (PD).

Dementia, which includes Alzheimer's disease, affects approximately 7 million American adults, and that number is expected to rise as the Baby Boom generation ages.

Patients with mild to moderately severe dementia received 12 weeks of treatment that included weekly transcranial/transnasal treatment sessions in the clinic and daily intranasal light therapy at home. The second phase involved a 4-week period without treatment. After 12 weeks, there was significant progress in memory recovery , visual attention, task switching, executive brain function, and other markers of cognitive performance.

Patients also slept better, had fewer outbursts of anger and anxiety, and wandered less after treatment. Because the off-treatment period saw significant declines, the authors suggest that continued treatment may be vital to managing dementia and AD.

Parkinson's disease is characterized by the slow degeneration of neurons involved in motor and non-motor function. A study focusing on age-related cognitive decline also observed 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 the progression of the disease.

Traumatic brain injuries and stroke

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

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 aids in the healing and restoration of damaged brain tissue and improves executive function , verbal learning, and other cognitive markers.

Complications of COVID-19, including chronic fatigue syndrome

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

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

An intriguing 2020 study suggests that using red light to stimulate the gut/lung microbiome axis may help heal chronic COVID-19-related conditions, including CFS.

Why does this matter? As the 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 reducing patients' susceptibility to COVID-19.

Red light therapy applied to the chest can improve airway function, blood oxygenation, reduce immune hyperactivity to prevent chronic inflammation, and alleviate depression caused by social isolation and anxiety about the future.

Fertility

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

Fibromyalgia

Fibromyalgia pain and muscle weakness can be alleviated with red light therapy. The treatment targets the entire hierarchy of mechanisms involved in 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 phase (regression to dormancy), thus keeping hair follicles in the growth phase for longer.

Hashimoto's hypothyroidism

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

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

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

Anti-inflammatory response

Chronic inflammation is considered 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 can be used preventively to reduce inflammation and thus eliminate the cause of major health problems.

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 article discusses a temporary increase in inflammation to support healing; once the inflammatory response is no longer necessary, red light inhibits inflammation. This ability to downregulate the inflammatory process is important for joint disorders, injuries, and other health challenges.

Muscle Recovery

For both weekend athletes and elite athletes, 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's even been suggested that red light therapy could provide an unfair competitive advantage!

Oral Health

Mouth pain can be distressing. Red light therapy can reduce dentin hypersensitivity and relieve pain from temporomandibular joint (TMJ) dysfunction.

Neuropathy and nerve health

A 2017 study found that nerve cells respond well to the biostimulatory 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, which supports normal nerve cell function. Together, Schwann cells and fibroblasts work together to form a "cord" that connects damaged nerve cells to healthy ones.

Pain relief

Whether your pain is acute due to an injury or you have chronic back or knee pain, red light therapy has been shown to be effective in relieving many types of pain:

• Pinched nerves
• Frozen shoulder
• Lower back pain
• Ankylosing spondylitis 
• Degenerative osteoarthritis of the knee

Respiratory Health

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

Skin health

Red light therapy is best known as a skin rejuvenation 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 infrared 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 improved endurance performance.

Tendonitis and other sports injuries

Red light therapy can treat bone fractures, sprains, muscle strains, and other sports injuries.

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

College athletes with sprains, bruises, 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 to an average of 19 days in the control group.

Weight loss and cellulite reduction

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

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

Red light therapy can cause fat cells to develop temporary punctures that allow them to release lipids : up to 80% of lipids after just four minutes and over 90% after six minutes. The released lipids are converted to carbon dioxide and are naturally expelled from the body.

Wound Healing

Red light therapy can minimize downtime after surgery and speed healing in wounds of 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 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 isolated for the first time using artificial light.
• Dr. Niels Ryberg Finsen first used artificial UV light for therapeutic purposes 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 for the invention of the laser. 
• The laser was developed in 1962, and Hungarian physician Endre Mester's low-level laser therapy device was launched in 1967 to treat skin cancer and speed 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 caring for the plants noticed that exposure to red LED light resulted in faster healing of hand injuries. This sparked interest in using red light to prevent the 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 first 12-wavelength spectrum for horticulture. The first high-power LED panel appeared in 2016. It featured a red wavelength and a NIR wavelength.
• Advances in LED technology over the past decade have brought red light therapy into the mainstream, where previously treatment was limited to healthcare professionals.
• Today, researchers have a deeper understanding of the mechanisms of action behind this natural treatment, and more treatment applications are emerging.

Side effects of red light therapy

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

Red light therapy is safe even for sensitive areas of the body, including the eyes and testicles. In fact, red light therapy has been used to improve eye health and increase testosterone. While red light therapy can improve eye health, the intense light emitted by a powerful LED device can cause eye fatigue. Eye treatments should last no more than three minutes and always under the supervision of an ophthalmologist. When not treating your eyes, wear light-protective glasses.

The many studies conducted on red light therapy have 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, longer is not better because the biological processes stimulated by light treatment cannot be hurried.

Red light therapy treatment at home vs. professional

In the past, red light therapy treatment was only available through dermatologists, wellness clinics, spas, and physical therapists who had light therapy devices that could deliver the light intensity needed for therapeutic benefits.

Today, you can enjoy the same results with a high-powered, medical-grade red light therapy device, without the ongoing treatment costs and travel.

Please note that small, handheld devices will not produce optimal results due to their lack of power. For maximum therapeutic benefits, choose a high-powered light therapy device that delivers maximum light energy output.

A combination of wavelengths is beneficial. Some LED devices include red and near-infrared light . Today, you can get devices that also feature blue light, in addition to red and NIR, for more comprehensive benefits, from skin health to pain management.

Whether you do light treatments in a clinic or at home, you'll need consistency and patience, as well as a high-output LED light.

Daily use is great, but the time it takes to see results depends on the specific treatment. Some benefits will be immediate, while others may take months to appear.

Red light therapy solutions

TheraFactor®'s industry-leading TheraPRO devices feature several key components:

• Highest light energy output (irradiance) in its power class
• FDA-cleared medical-grade devices for professional results
• A patented combination of 8 different red and NIR wavelengths plus a blue wavelength based on extensive light therapy research

A natural way to improve well-being

Red light therapy is a natural, non-invasive treatment that stimulates beneficial biological effects for an incredible variety of targeted and widespread applications.

More studies are emerging that support red light therapy as a complement to conventional medical treatments. Be sure to check out TheraFactor 's article and science hub to discover the many ways red light therapy can support your health.