A Guide to Red Light Therapy

What is red light therapy (LLTT) or Photobiomodulation?

If you’ve never heard of infrared light therapy, you may be a little confused as to how light can help heal. Much like infrared saunas use heat to penetrate the skin and initiate cellular activity, red light treatment uses red low-level wavelengths of light to stimulate superficial or deeper cells through molecular mechanisms that will be discussed below; the use of light-emitting diodes (LED) or low-level laser therapy stimulates cellular activity to achieve therapeutic benefits through several different mechanisms at the cellular level. Studies have shown that a specific wavelength (600-880nm) of red light is beneficial to stimulate cells to elicit various physical and physiological effects. Red light therapy also goes by several other names including photorejuvenation, LILT (Low-Intensity Light Therapy), LLLT (Low-Level Laser or Low-Level Light Therapy), photobiomodulation, or biostimulation.

Infrared light therapy is a painless, non-ablative, and non-invasive procedure that reports show is generally safe for all skin types with little known side-effects when used appropriately.

Bioactive light and the body

The human body needs light to be healthy — and it’s not just in the form of UVA and UVB light from the sun. Most people associate like with practical uses but forget that our bodies and cells need specific wavelengths of light to function optimally.

For a lot of us, the lifestyle we lead forces us to be boxed in an office anywhere from height to twelve hours a day. The result of that is that most of us don’t get adequate amounts of light that our bodies need to function normally, which leads to a state of light deprivation. Light deprivation can cause a multitude of issues just as sleep deprivation can on hormones and neurotransmitters.

There are 5 different types of light that are bioactive within the human body, of which red light is a part of:

Blue light — Involved in the control of circadian rhythm, blue light is the shortest wavelength of the visible light spectrum, meaning it also has the most energy. Blue light is visible light ranging from 380-500nm and constitutes approximately one-third of all visible light. While the main source of blue light is sunlight, other sources include fluorescent lighting, LED, and display screens on mobile devices (tablets, laptops or computers, phones, and TVs). As it impacts circadian rhythm, blue light also affects the production of many different neurotransmitters and hormones.

UV light — UV light, the main source of light from the sun, is the spectrum of visible light between 180-400nm and induces synthesis of vitamin D3¹ Trusted SourceThe benefits and risks of ultraviolet (UV) tanning and its alternatives: the role of prudent sun exposure
Raja K. Sivamani, MS,a Lori A. Crane, PhD, MPH,b and Robert P. Dellavalle, MD, PhD, MSPHb,c,d

Far-infrared — Far-infrared is a wavelength of light that is not on the visible spectrum. It acts to increase arterial blood flow, peripheral blood circulation, improve endothelial function, reduce pain, reduce blood pressure, and promote capillary dilatation.² Trusted SourceFar-infrared therapy for cardiovascular, autoimmune, and other chronic health problems: A systematic review
Shanshan Shui,Xia Wang, John Y Chiang and Lei Zheng

Red light –The red light spectrum from 600-700nm acts on the mitochondria in cells to stimulate increases in ATP (energy) production and works against nitric oxide and oxidative stress that weaken cells.

Near-infrared (NIR) — Just above the red light is the NIR spectrum at 700-1100nm that acts on many of the same pathways as red light, especially with respect to penetrating mitochondria to increase ATP production.

It’s important to remember that while all 5 types of light are necessary for the body, the benefits of them depend on the correct amounts of each of them.

Infrared vs. Near Infrared

The difference between red light therapy and near-infrared therapy simply comes down to the fact that the two fall into different regions of the light spectrum. While red light falls into the visible part of the light spectrum, between 600-700nm, and is used to treat the surface of the skin, near-infrared wavelengths fall into the invisible part of the spectrum, between 900-1100nm. Research shows that NIR (near-infrared) frequency penetrates deeper into the body to elicit a therapeutic effect for cells, especially mitochondria, which respond to near-infrared wavelengths. Many studies suggest that this wavelength of light triggers an increase in cell metabolism, protein synthesis, and antioxidant activity. It also helps to reduce levels of oxidative stress, inflammation, and pain intensity while simultaneously triggering cell proliferation and regeneration.

How does red light therapy work?

Due to the combination of high degree of skin penetration and absorption by respiratory chain components, most research shows that light in the spectral range from 600 to 680 nm and 800 to 880 nm is beneficial for promoting wound healing, tissue repair, and skin rejuvenation ³ Trusted SourceA Controlled Trial to Determine the Efficacy of Red and Near-Infrared Light Treatment in Patient Satisfaction, Reduction of Fine Lines, Wrinkles, Skin Roughness, and Intradermal Collagen Density Increase
Alexander Wunschcorresponding author and Karsten Matuschka, working on three levels: the molecular, cellular, and tissue.

In contrast to other forms of light therapy such as laser or intense pulsed light (IPL), which induce secondary tissue repair by causing controlled damage to the epidermis or dermis, photobiomodulation (PBM), or red light therapy, bypass this initial destructive step by directly stimulating skin regeneration processes. Certain cell types, namely fibroblasts, keratinocytes, and immune cells (mast cells, neutrophils, and macrophages), that are important for skin and tissue regeneration are stimulated by specific wavelengths with significant tissue penetration properties. When a certain wavelength is used on the skin, it initiates increased cell proliferation, migration, and adhesion ⁴ Trusted SourceA Controlled Trial to Determine the Efficacy of Red and Near-Infrared Light Treatment in Patient Satisfaction, Reduction of Fine Lines, Wrinkles, Skin Roughness, and Intradermal Collagen Density Increase
Alexander Wunschcorresponding author and Karsten Matuschka.

There are two main mechanisms that red light and near-infrared light work on:

Mechanism # 1: Stimulates mitochondrial energy production (ATP)

The wavelengths of red light and NIR have been found to penetrate cells and directly activate mitochondria, which in turn stimulates increased energy production. Rodent studies show that red light and near-infrared light have the ability to increase proton electrochemical potential, increase ATP synthesis, increase RNA and protein synthesis, and cause increases in oxygen consumption, membrane potential, and enhance the synthesis of NADH⁵ Trusted SourceBiphasic Dose Response in Low Level Light TherapyYing-Ying Huang.

Mitochondria are so important to the human body because they power virtually every process that occurs within organs, so to increase the efficiency of mitochondria means to increase the amount of energy each cell receives, translating directly into a more optimal body function.

In the four stages of cellular respiration — which is where ATP is created –, red light and NIR have the most profound effect on the last stage, oxidative phosphorylation. In order for the light to elicit an effect on the body, it must be absorbed by something within a cell or organism. In this case, humans have several lights absorbing compounds — hemoglobin, cytochrome c oxidase, myoglobin, flavins, flavoproteins, and melanin, all of which absorb certain wavelengths of light and translate it into biological effects. Of special importance is cytochrome c oxidase, found inside the mitochondria. Cytochrome c oxidase plays an important role in the respiratory chain and the production of ATP. When red and near-infrared photons hit the photoacceptors on cytochrome c oxidase, it assists the mitochondria in using oxygen more efficiently, which increases energy production.

It’s important to understand that mitochondria cannot generate ATP without sufficient oxygen and there are certain compounds within the body that competes with oxygen and inhibit this, namely nitric oxide (NO). So in order for ATP production to generate at as high a level as possible, NO must not displace oxygen; this can be done using red light therapy, as light can reverse the inhibition caused by NO binding to cytochrome oxidase.

Mechanism #2: Hormesis (initiation of low-dose metabolic stress)

The second mechanism by which red and infra-red light affect cells is through a process called hormesis — a transient low-grade metabolic stressor that stimulates adaptations that are beneficial to health.

It’s similar to the concept of exercising to enhance body processes. Exercise works by transiently creating metabolic stress on the body and temporarily increasing the production of free radicals. In response to this, the body must adapt through things like enhanced cardiovascular efficiency, improved blood circulation to the muscles, and strengthening mitochondria, but also by downregulating genes involved in the inflammatory response and oxidative stress and upregulating genes involved in energy production and internal antioxidant pathways.

Red light and infra-red light essentially stress the mitochondria so it sends signals to the nucleus about which genes to express. Specifically, the same defense systems that are activated in response to exercise are activated in response to increases in free-radicals from red and NIR light. These pathways help to eliminate inflammation and free radicals, making cells more tolerable to stress, reduces inflammation, prevents the buildup of free radicals, and makes cells more resilient.

What are the benefits of red light therapy?

Aside from reducing the signs of aging, red light therapy has a multitude of other benefits. It can help to address a number of other conditions, including:

Combats chronic fatigue and increases energy

One of the most well-studied benefits of red light therapy is its ability to increase ATP (energy) production. Red light and NIR light are able to penetrate directly through cells to activate mitochondria, where they upregulate cellular energy production. When red light hits the photoacceptor (enzyme) cytochrome c oxidase, which is present in all mitochondria, it increases the efficiency by which mitochondria use oxygen to produce ATP. Oxygen is needed to produce ATP, thus as exposure to red light increases, cellular use of oxygen and production of ATP increases, providing the body with more energy. As such, individual organs and organ systems can function more optimally.

Reduces adipose tissue and increases fat loss

NIR and red light have been said to increase weight and fat loss by increasing the release of fat stores into the bloodstream to be burned for energy. One study, specifically, found that low-level laser of an appropriate wavelength applied three times per week for two weeks can significantly reduce circumference at a certain targeted tissue site due to a reduction in adipose (fat) layer⁶ Trusted SourceLow-Level Laser Therapy as a Non-Invasive Approach for Body Contouring: A Randomized, Controlled StudyRobert F. Jackson, MD, Doug D. Dedo, MD, Greg C. Roche, MD, David I. Turok , and Ryan J. Maloney.

It’s important to note, however, that the ability to modulate cellular metabolism and provoke a biological response is highly dependant on the intensity, wavelength, and frequency of the light being applied.

One of the proposed mechanisms behind this is attributed to the formation of micropores in the membrane with the application of 635nm wavelength of light. As such, the pores allow the release of intracellular lipids from fat cells ⁷ Trusted SourceLow-Level Laser Therapy for Fat Layer Reduction: A Comprehensive ReviewPinar Avci, MD,Theodore T. Nyame, MD,Gaurav K. Gupta, MD, PhD,Magesh Sadasivam, MTech,and Michael R. Hamblin. Another possible mechanism is that light therapy stimulates mitochondria in adipocytes, which increases the synthesis of ATP and upregulates cAMP. An increase in cAMP subsequently activates protein kinases that stimulate enzymes that convert triglycerides to fatty acids and glycerol, both of which can pass through the pores of cell membranes and thus reduce the size of adipocytes ⁸ Trusted SourceLow-Level Laser Therapy for Fat Layer Reduction: A Comprehensive ReviewPinar Avci, MD,Theodore T. Nyame, MD,Gaurav K. Gupta, MD, PhD,Magesh Sadasivam, MTech,and Michael R. Hamblin.

Aids muscle recovery

Not only does red light therapy appear to enhance the effects of exercise, but it also makes a profound impact on the body’s ability to recover. As muscle tissue is particularly dense with mitochondria, it responds incredibly well to red light. Because mitochondria play such an important role in ATP production as well as involvement in the mechanisms of cellular healing, red light therapy and NIR have been shown to be highly beneficial for muscle repair and recovery.

Red light has been shown to increase the production of antioxidants in the body, which help to combat the free radicals produced during exercise and prevent oxidative stress and tissue damage. As well, red light and NIR help to reduce inflammation levels⁹ Trusted SourceEffects of Light-Emitting Diode Therapy on Muscle Hypertrophy, Gene Expression, Performance, Damage, and Delayed-Onset Muscle Soreness: Case-control Study with a Pair of Identical TwinsFerraresi C, Bertucci D, Schiavinato J, Reiff R, Araújo A, Panepucci R, Matheucci E Jr, Cunha AF, Arakelian VM, Hamblin MR, Parizotto N, Bagnato V.,which may help to decrease muscle fatigue and soreness.

Studies have also shown that when applied prior to exercise, LLLT can improve muscular performance and accelerate recovery ¹⁰ Trusted SourcePhotobiomodulation therapy before futsal matches improves the staying time of athletes in the court and accelerates post-exercise recoveryDe Marchi T, Leal-Junior ECP, Lando KC, Cimadon F, Vanin AA, da Rosa DP, Salvador M..

Speeds up wound healing and tissue repair

Initial studies on the effects of light therapy showed that it is beneficial for wound healing and can help to close wounds — even slow healing or resistant wounds — up to 20% faster than without treatment.

This effect can be partially attributed to increases in blood circulation and the formation of new capillaries, meaning the impacted area receives increased blood supply and nutrients needed to initiate and maintain the healing process. This is accomplished through:

• Phagocytosis (removal of dead and damaged cells)
• Increased ATP production in skin cells
• Increased fibroblast production
• Increased blood flow (great supply of oxygen and nutrients)
• Stimulates collagen synthesis
• Stimulates lymph activity
• Stimulates formation of new connective tissue and capillaries on the wound surface

Helps with symptoms of anxiety and depression

While there is still a lot of research to do when it comes to treating anxiety and depression with red light therapy, the available research shows great promise. Serotonin is an important neurotransmitter involved in mood control and is research shows decreased levels in individuals suffering from anxiety, depression, and other mood disorders. The monoamine-deficiency hypothesis proposes that depression is a result of an imbalance and deficiency of specific monoamine neurotransmitters, including serotonin (5-HT), dopamine, and noradrenaline in the central nervous system¹¹ Trusted SourceTranscranial photobiomodulation prevents anxiety and depression via changing serotonin and nitric oxide levels in brain of depression model mice: A study of three different doses of 810 nm laser.Eshaghi E, Sadigh-Eteghad S, Mohaddes G, Rasta SH.. Studies also show that many individuals with depression have altered blood flow to the frontal cortex of their brain. As NIR and red light produce an increase in blood circulation, it’s plausible to assume that this could be one mechanism for improving symptoms.

Several studies show that NIR light therapy has an anti-anxiety and anti-depressive effect, which may be attributed to an increase in 5-HT (serotonin) and a decrease in nitric oxide (NO); studies have shown NO inhibiting drugs to be effective in the treatment of depression¹² Trusted SourceTranscranial photobiomodulation prevents anxiety and depression via changing serotonin and nitric oxide levels in brain of depression model mice: A study of three different doses of 810 nm laser.Eshaghi E, Sadigh-Eteghad S, Mohaddes G, Rasta SH.. One particular study found that a dose of 8 J/cm2 caused the maximum anti-anxiety and anti-depressive effects, while anything higher or lower was not beneficial¹³ Trusted SourceTranscranial photobiomodulation prevents anxiety and depression via changing serotonin and nitric oxide levels in brain of depression model mice: A study of three different doses of 810 nm laser.Eshaghi E, Sadigh-Eteghad S, Mohaddes G, Rasta SH.. Another study found that 2 weeks of NIR treatment in patients with depression improved outcomes for both the HAM-A (Hamilton Anxiety Rating Scale) and HAM-D (Hamilton Depression Rating Scale) — measures of severity of symptoms¹⁴ Trusted SourcePsychological benefits 2 and 4 weeks after a single treatment with near infrared light to the forehead: a pilot study of 10 patients with major depression and anxietyFredric Schiffer, Andrea L Johnston, Caitlin Ravichandran, Ann Polcari, Martin H Teicher, Robert H Webb & Michael R Hamblin ..

Improves hair growth

Hair growth takes place in three distinct stages: anagen (growth phase), catagen (hair transition to the skin surface), and telogen (resting phase when strands are released and fall out, where the follicle then remains inactive for 3 months before the whole process is repeated).

Red and NIR have been shown to stimulate hair follicle cell proliferation and increase the number of follicles in the anagen stage. Subjects received a total of 18 treatments over a 12-week period to the vortex of the scalp. Outcomes were measured based on four variables: number of hairs present, presence of anagen hairs, number of hairs containing melanin, and presence of Ki76, a marker of hair follicle cell proliferation. Results showed that all subjects showed improvements in at least one measure¹⁵ Trusted SourceThe growth of human scalp hair mediated by visible red light laser and LED sources in malesLanzafame RJ1, Blanche RR, Bodian AB, Chiacchierini RP, Fernandez-Obregon A, Kazmirek ER.

Improves skin complexion and increases collagen synthesis

Collagen is the most abundant protein in the human body and is critical to keeping the skin looking healthy and young. It’s in everything from skin and hair, to joints, bones, and muscles. In a study on the effect of photobiomodulation on skin appearance, results showed significant improvements in skin complexion and skin feeling, skin roughness, and collagen density using a light wavelength of either 611–650 or 570–850¹⁶ Trusted SourceA Controlled Trial to Determine the Efficacy of Red and Near-Infrared Light Treatment in Patient Satisfaction, Reduction of Fine Lines, Wrinkles, Skin Roughness, and Intradermal Collagen Density IncreaseAlexander Wunschcorresponding and Karsten Matuschka..

As well, NIR can help to reduce and/or improve the appears of scars. Hypertrophic scars are benign tumors of the skin that result following trauma, surgery, or acne and are generally quite difficult to eradicate. They form as a result of two main reasons: fibroblastic proliferation and excess collagen deposits; there is an imbalance between the rate of collagen biosynthesis and its degradation. Studies have shown considerable improvements in the appearance of scars following treatment with red light or NIR light used to alter the wound healing process to avoid or reduce the formation of hypertrophic scars ¹⁷ Trusted SourceLow-level laser (light) therapy (LLLT) in skin: stimulating, healing, restoring
Pinar Avci, MD, Asheesh Gupta, PhD,Magesh Sadasivam, MTech, Daniela Vecchio, PhD, Zeev Pam, MD, Nadav Pam, MD and Michael R Hamblin, PhD
.

Improves joint health

As light therapy has a profound impact on reducing inflammation, it’s been shown as a beneficial therapy for the treatment of joint disorders, specifically arthritis. There are four main mechanisms by which LLLT exerts its effects ¹⁸ Trusted SourceComparison of low level laser, ultrasonic therapy and association in joint pain in Wistar rats.Coradini JG, Mattjie TF, Bernardino GR, Peretti AL, Kakihata CM, Errero TK, Escher AR, Bertolini GR.

Reducing pain

Modulating the inflammatory response (decreases release of pro-inflammatory cytokines)
Increases blood circulation to the affected area
Stimulates wound healing and repair mechanisms to the damaged area (connective tissue growth)

Relieves pain and inflammation

Red light and NIR light therapy have been shown to be effective for treating chronic inflammation due to its ability to suppress the release of pro-inflammatory cytokines, which is particularly important for joint disorders, traumatic injuries, lung disorders, and disorders in the brain.

Light therapy works by reducing oxidative damage in tissues and increasing blood supply and nutrient delivery, especially in tissues with a high density of mitochondria. It also helps to increase the release of anti-inflammatory cytokines.

With respect to pain relief, red and NIR light therapy has been shown to be effective at decreasing pain sensation by changing tissue opioid receptors, initiating changes in substance P (the neurotransmitter associated with pain) and interrupting nerve transmission and pain sensation. LLLT applied with a sufficient level of intensity has been shown to inhibit action potentials (nerve impulses), which has a cascade effect to suppress the activation of cortical areas associated with pain ¹⁹ Trusted SourcePro- and anti-inflammatory cytokine content in human peripheral blood after its transcutaneous (in vivo) and direct (in vitro) irradiation with polychromatic visible and infrared light.Zhevago NA1, Samoilova KA.

Minimize cellulite

Cellulite appears on the skin’s surface as a result of unhealthy collagen and elastin in the skin layers, in conjunction with excess fat. Red and NIR light has been shown to help eliminate, or reduce the appearance of cellulite in three ways:

Boosts collagen and elastin production, as well as supports the health of the extracellular matrix — the fibrous structure that supports cells
Increases blood circulation in the surrounding area
Causes release of stored fat from fat cells into blood circulation where it can be burned

Research has shown that red light and NIR light can help to improve skin tone and enhance smoothness ²⁰ Trusted SourceA double-blind, placebo-controlled randomized trial evaluating the ability of low-level laser therapy to improve the appearance of cellulite.Jackson RF1, Roche GC, Shanks SC..