What is Red Light Therapy?
5 keys for the best red light therapy results
By Da Vinci Medical
June 25, 2020
Today, red light therapy has become a panacea for treatment of health issues with a broad and growing range of stated benefits. Claims include tissue repair, immune boosting, collagen production, treatment for hair loss, mental depression, skin disorders, arthritis, and even cancer. Because it is a noninvasive and easy to use treatment, many have accepted it for these uses, despite knowing that many of these claims are not clinically proven, or FDA cleared, or covered by insurance companies. There are several red light therapy devices available in the market, from low cost to expensive, with no consensus about treatment features and overall effectiveness.
We will review what red light therapy is proven effective for and what it is not, although the basic science research of light treatment can be overwhelming since it incorporates physics, chemistry, and biology. Physics encompasses light–tissue interactions, tissue optics, and light source properties; chemistry looks at light absorption, chromophores, the photobiomodulation of reactive oxygen species and photochemical reactions; and biology covers cell signaling, transcription factors, proliferation, and migration. We will also provide “5 Keys for the Best Red Light Therapy Results.”
What Red Light Therapy Is
Red light, as a standalone short wavelength system, is for treating the skin and superficial conditions (dermatological applications) as it cannot penetrate deep into the body.
Red light wavelengths combined with one or more infrared light (long) wavelengths is now referred to as Photobiomodulation Therapy (PBMT). Photobiomodulation therapy is the application of red and near-infrared light to tissue that has been compromised by injury, disease, or degeneration. It is the use of these clinically-determined wavelengths that increases circulation and the synthesis of cellular energy. This light energy is readily absorbed by chromophores in the mitochondria of the body’s cells, which activates metabolic energy processes. These wavelengths of light promote ATP production, which boosts energy transport within cells, leading to increased healthy cell function and cell proliferation.
The natural metabolic processes are enhanced by PBMT to help reduce the damaging effects of oxidative stress. Oxidative stress, or an influx of free radicals in the body, has been linked to health issues from wrinkles to more serious diseases like diabetes and cancer. Photobiomodulation therapy helps promote the body’s natural processes for metabolizing free radicals and minimizing the damage they cause. This boost in the body’s natural healing cycle helps reduce inflammation and promotes healing of damaged tissue. PBMT increases the rate and quality of tissue repair, improves muscle performance, enhances recovery, and reduces pain. PBMT is a safe and relaxing mode of recovery that has no known negative side effects.
The following applications are cleared by the FDA:
Relaxation of muscles and relief from muscle spasms
Temporary relief of minor muscle and joint aches, pain and stiffness
Restoration of motion to joints
Temporary relief of minor pain and stiffness associated with arthritis
Temporary increase in blood circulation
What Red Light Therapy Is Not
Many red light companies are promoting applications that do not use red light for these specific treatments or are not FDA cleared at this time.
NOTE: The FDA does not approve medical lasers. Medical lasers are only cleared by the FDA for specific indications for use, which are referred to as FDA 510k Clearance. Companies that use “FDA Approved” in their marketing for red light therapy products and lasers are in violation of FDA regulations.
Cancer. The FDA has not cleared red light therapy to treat cancer.
Surgical lasers may be used for cancer surgery and other therapy lasers are used for pain relief and recovery from certain cancers. Photodynamic therapy (PDT) that works with photosensitizer drugs may incorporate red light as part of their systems and have been cleared by the FDA.
Psoriasis. The FDA has not cleared red light therapy to treat psoriasis. UVA / UVB devices and Excimer 308nm lasers are used to treat psoriasis.
Depression. The FDA has not cleared red light therapy to treat depression, including season affective disorder (SAD).
Full spectrum 10,000 lux light boxes or blue light devices are being used to treat SAD, as well as circadian rhythm and sleep disorders.
Wounds. The FDA has not cleared red light therapy to treat wounds.
Therapy lasers using infrared wavelengths are being used in veterinary medicine to treat animal wounds.
Red Light Therapy Panels are Not Therapy Lasers.
Many red light companies are using incorrect terms for red light therapy, including: Low Level Laser Therapy (LLLT), cold laser therapy, soft laser therapy, low-intensity laser therapy, low-energy laser therapy, and bio- stimulation laser therapy. A red light therapy product is a Light Emitting Diode (LED) system and not a laser. An LED product releases light in many directions, with the result that the light is often weak and diffused and is referred to as an incoherent waveform. In contrast, a laser device releases light in which all the light waves move in phase together in both time and space and is referred to as a coherent waveform. A laser has a very tight beam that is strong and concentrated.
Red Light Therapy Companies are Falsely Promoting Laser Clinical Studies.
Of the thousands of referenced and reported clinical and scientific studies and papers available, most are exclusively done with therapy laser devices as the medically-beneficial light source. Currently, many red light therapy companies are falsely promoting therapy laser studies to support and validate their medical efficacy. They attempt to document claims for the effectiveness of red light in highly marketable conditions (such as cancer treatment, wound healing and immune system boosting) to generate marketing publicity.
5 Keys for the Best Red Light Therapy Results
Key #1: Treat the Cause and Not Just Symptoms with Light Therapy (Red Light)
A primary focus of health care is to treat the immediate issue, but not necessarily the underlying cause. Treating only the symptoms can bring quick relief but not long term benefits. Doctors will issue various prescriptions or recommendations for Rx medications and over-the- counter (OTC) products, or for therapeutic modalities such as TENS, ultrasound therapy, vibration, massage, heat, and cold therapy products. People assume that these products are making their condition better, but the reality is that they often only help to temporarily relieve pain and discomfort.
With an estimated 1 of 6 people in America coping with constant pain, an increasing number are dealing with the vicious cycle of opioid treatment. With long-term use, the body develops an opioid tolerance and people start taking stronger doses just to get the same pain relief effect. Taking stronger doses leads to the potential risk of addiction and overdose. Even OTC pain medications and NSAIDs like aspirin, acetaminophen and ibuprofen can have potentially dangerous side effects like increased risk of heart attack or gastrointestinal issues. Many OTC pain medications were also not meant to treat chronic or long-lasting pain.
Treating symptoms can not only be financially costly, but also detrimental to health with the result of lower overall quality of life.
Light therapy including red light is emerging as a new treatment option that is different because it treats the cause and not just the symptoms of many healthcare conditions. It is a drug-free, non-invasive treatment that deals with the underlying cause of pain through repair of damaged cells. It does this by safely bringing energy to stimulate the body’s own healing mechanisms without side effects or secondary problems.
Summary. The key to treating pain is to treat the cause of pain and not just the symptoms. This can be achieved by using light therapy products that have the proper wavelengths, dosage levels and treatment coverage. Not all light therapy and red light products are equal, and many manufacturers do not develop equipment that properly considers the science and principles of the physics of light, resulting in inadequate or inappropriate dosing levels and marginal or inconsistent results. It is important to only use products that are proven safe, effective for their intended uses or applications and compliant with the FDA and other regulatory agencies.
Key #2: Combine Red Light with Multiple Infrared (IR) Wavelengths
Red is a part of the electromagnetic radiation visible spectrum that includes violet, indigo, blue, green, yellow, orange and red which are arranged in order of increasing wavelength and decreasing frequency. This narrow band of visible light is also known by the acronym ROYGBIV. Red is a short wavelength in the 600 – 700nm range.
Red light has been used in healthcare for many years, primarily in dermatology, to successfully treat various inflammations of the skin that include acne and rosacea. These skin conditions do not require deep penetration to be clinically effective. Red light is often paired with blue light, as the blue light targets the bacteria associated with acne and red light targets the inflammation under the skin. Blue light is a shorter wavelength than red light and penetrates even less while scattering more.
Several red light therapy companies incorrectly claim their products are absorbed deep into tissues of the body. These claims use numbers from the metric system with stated penetrations of “8 – 10mm” deep. However, converting these numbers to the US measurement system reveals that the penetration is actually less than 1⁄2” depth into the skin (1/2 inch equals 12.7 mm), which is correct and ideal for skin treatments but not deeper therapies.
The Grotthuss-Draper Law of Photochemistry (the First Law) states that light must be absorbed for photochemistry to occur. If light of a particular wavelength is not absorbed by a system then no photochemistry will occur, and no photobiological effects will be observed, no matter how long one irradiates with that wavelength of light. Many clinical studies and published papers using low-level therapy lasers or red light LED devices, showing marginal or almost no outcomes, would not and should not have been published if the authors and the reviewers had properly understood the First Law of Photochemistry.
Wavelength is the prime determinant of light penetration into tissues of the body. Each wavelength has very specific capabilities regarding cell absorption. Red and other visible light are short wavelengths that are absorbed or penetrate superficial skin and tissues.
On the electromagnetic radiation spectrum, infrared (IR; non-visible) wavelengths in the 780 – 1400nm range are longer wavelengths and are transmitted with a greater percentage of the light penetrating deeper into tissues of the body.
Combining red light (short) wavelengths with one or more infrared (long) wavelengths is the optimal method of achieving positive therapeutic outcomes and is now referred to as Photobiomodulation Therapy (PBMT).
Photobiomodulation Therapy is a new name for light therapy. In fact, the term marks the acceptance of light therapy into the practice of western conventional medicine. The definition of Photobiomodulation Therapy is the use of light to cause a change in human or animal life: “Photo” means light; “Bio” means life; “Modulation” means a change in something.
Summary. Red light only will provide results for skin treatments but not for other conditions that require deeper penetration. The key to achieving biological results is by combining red with one or more infrared light (IR) wavelengths. Different wavelengths are more readily absorbed by diverse tissues in the body and combining multiple wavelengths increases the overall saturation and depth of penetration of the light energy.
Key #3: Optimize Treatment Dosages
The key to achieving biological results with photobiomodulation is optimizing treatment dosages. Dosage is a combination of wavelength, power levels, treatment distance and exposure times. If wavelength determines the depth of penetration of a laser’s energy, then power determines its saturation at the targeted depth. When treatment results are lacking it is often due to under-dosing by not providing enough light energy, using treatment times that are too short, or not using technology and products that have enough power. Dosage refers to the amount of energy per unit area of tissue surface. Energy is measured in joules and the area in square centimeters, and thus the dosage is joules per square centimeter (J/cm2). With PBMT units, irradiance levels can be affected by the wide variance in treatment distances, which can be manipulated during power level meter testing.
Red light therapy companies with inferior products and limited specifications often base their treatment protocols and recommendations around their limitations. For example, if a product does not have certain wavelengths, statements that “you don’t need these wavelengths” or “you don’t need multiple wavelengths” will be provided.
Many of these companies have products with limited power output, and false claims are made about “over-dosing” and “too much light energy is harmful.” Often the Arndt-Schulz law, or Biphasic Dose Response, is quoted as proof of overstimulation. This refers to “U-shaped” dose- response curves observed for some external agents: below a threshold there is no effect; a small amount of something has a small effect; a moderate amount has a large effect; and a large amount has either no effect or an adverse effect. It is important to consider that this is not a general “Law” and it is not based on fundamental principles or cellular processes. To claim that more than X amount of light radiation is inhibitory because of the Arndt-Schultz law is completely unfounded.
Much of the research that attempts to narrow the optimal treatment parameters for light therapy has been performed in vitro (laboratory studies) and not in vivo (clinical studies). These laboratory studies have the advantage that most of the parameters can be easily measured and well controlled, and many experimental results have indeed shown an optimal dose region for biostimulation above which inhibition takes place. More commonly referred to as “hormesis,” the Arndt-Schulz law thus describes a substances’ (but not light’s) capacity to inhibit biological processes at high concentrations and stimulate them with minute amounts. However, its extrapolation to light and laser therapy has not been unequivocally substantiated.
Light therapy biostimulation has been reported with a wide range of doses and is explained by the vast differences in irradiating tissue cultures in a laboratory setting (in vitro) versus treating a human body in a clinical setting (in vivo). Historically, the treatment parameters used for light therapy were based in the mid-to-late 1960s on Endre Mester’s initial reports that a dose of 1 J/cm2 from a ruby laser caused significant stimulation of healing of cutaneous wounds and burns in a mouse model. In both his in vitro and animal experiments, Mester tested the effects of radiant exposures (fluences) ranging from 0.05 to 4.0 J/cm2 and reported that these fluences were effective. A review of the literature on in vivo rodent wound studies determined that use of red or Near-IR wavelengths, at a range of fluences with a median of 4.2 J/cm2, resulted in significant improvement in cutaneous wound healing.
When clinicians began to use light therapy to treat tissues located deeper in the body, they persisted in using these low dosage parameters that were not appropriate for translation to deep-tissue treatment. The outcome was publication of negative results, which led to the conclusion that there was inadequate evidence to recommend light therapy for clinical use. We now understand that these negative studies were due to incorrect device and treatment parameters for transcutaneous treatment of deeper structures because of low dosages, treatment times and power levels.
Summary. Optimal Dosage is key to clinical results. Use only Photobiomodulation Therapy products with technologies and protocols that incorporate the best multiple wavelengths, the highest power levels and the most variable treatment times that will generate the best dosage levels resulting in positive outcomes.
Key #4: Treat the Entire Body
The therapeutic effectiveness of Photobiomodulation Therapy is significantly increased by treating the entire body at one time. This allows for maximum dosage levels that are important to achieve clinical outcomes with the shortest possible treatment exposure times.
Many light therapy units are varying sizes of one-sided flat panels that are used to treat targeted areas of the body. Even panel units that may be as large as 5 - 6’ in length cannot compare to a true 360 degree full body system, and treatment times with panel units are much longer. There is no guarantee that the body responds the same to a single more powerful treatment encompassing the entire body versus longer treatment times required from rotating various body parts through individual treatment sessions.
Limitations exist with flat light panel unit and even with modular connecting systems where multiple flat panels are linked together. These limitations include the technology required and the physical dimensions of the specific size light panel.
For example, the power level is an important determinant of total dosage for a treatment. To increase the power level in a product requires adding more light emitting diodes (LEDs) or adding larger size diodes. This requires physical space that is not possible in a flat panel. In addition, when power levels are increased the extra amount of heat that is generated must be managed though a cooling system. The need for a large internal cooling system also requires the physical space that is not possible in flat panels. A limited space environment presents another problem of the inability to add additional wavelengths, which are essential to optimizing dosage levels.
Summary. PBMT treatment of the entire body at one time provides different and better results, in a shorter amount of time, than treating smaller areas of the body.
Key #5: Experience the Benefits of Pulsing
Photobiomodulation devices can be manufactured to operate in various modes, primarily continuous or pulsed mode. Continuous wave emission has no interruption during the delivery of the light energy, but requires specific technology to sustain the constant output without overheating or breakdown.
Pulsed operation of light therapy refers to any device not classified as continuous wave, so that the optical power appears in pulses of specified duration at selected repetition rate. The words pulsing and frequency are used interchangeably to describe the same concept: the interruption of energy flow on a predetermined basis. When referring to light therapy, most practitioners use the term frequency to mean the pulse frequency of the device. The hertz (symbol: Hz; definition: 1/s) is a unit derived from time which measures frequency in the International System of Units (SI). Frequency is how often something happens; for example, a frequency of 1 hertz means that something happens once a second. A chopped beam is a continuous beam that is electronically or mechanically switched between on and off. During the “on” moments it typically has the same output power as in continuous mode, but since it’s not on all the time the average output power is less than when continuous.
Different pulse frequencies elicit different physiological response from the body. Depending on the condition being treated and the patient’s response, it is important to have the ability to select one or more hertz levels.
Some light therapy units offer pulsing frequencies but can only provide low power levels or one wavelength, with the result that pulsing does not generate significant differences or outcomes. Research is currently ongoing that combines high power and multi-wavelength systems with specific pulse frequency settings.
Summary. The role and function of pulsing frequencies is becoming more important as it’s combined with high power levels and multiple wavelengths for PBMT.
It's now possible to take advantage of red light therapy at home using cutting-edge devices.
One example is a light bed called TheraLight 360 HD. TheraLight is considered the most powerful commercial option for both consumers and practitioners because it can be used by
anyone and does not require a healthcare license to operate. This light bed (also called a pod or capsule) offers brief but powerful 10-15 minute sessions and has a unique 360° light exposure design. It offers 4 deep penetrating wavelengths (1 red and 3 near-infrared) with adjustable frequencies and power output, all controlled with a wireless tablet.
According to the makers of TheraLight 360, the bed can be used for both general wellness and as a medical device, for purposes including:
Relief to joint pain and stiffness
Temporary pain relief to minor arthritis pain or muscle spasm
Increase in blood circulation
Faster rate of recovery after injury
Challenge with Laser Studies: Age of the Study and Out-dated Technology
Many studies were performed in the years from 1990 to mid-2000s, with technology that is inferior to today’s, and often before the FDA issued 510k usage clearances. These studies are too old to be relevant and many state the same conclusions: “the results were not substantial or significant and more research is needed.”
Challenge with Laser Studies: Location of the Study and Low Quality Control
Many studies were not performed in the USA, with varying levels of quality control systems in place and questions regarding final data analysis and reporting.
Challenge with Laser Studies: High Placebo Effect for Light and Lasers
Individuals receiving a light or laser therapy treatment may initially report a positive outcome, however these results might not be repeated with future treatments. These inconsistent results can be attributed to the placebo effect.
Applications for Light and Laser Treatments Outside of Red Light Therapy
There are multiple applications for lasers and light therapy in cancer treatments that include:
Low Level Therapy Lasers
Low-level Therapy Lasers are a new non-invasive treatment option using infrared wavelengths for oropharyngeal mucositis, a common side effect of many oncological treatments.
Surgical Lasers can be used instead of blades or scalpels to cut tissue and remove polyps or tumors. They are more precise than scalpels, so they do less damage to normal tissue and patients have less pain, bleeding, swelling, and scarring.
Photodynamic therapy (PDT) is a two-stage treatment that combines light energy with a drug (photosensitizer) to destroy cancerous and precancerous cells after light activation. Photosensitizers are activated by a specific wavelength of light energy, usually from a laser. The photosensitizer is nontoxic until it is activated by light. However, after light activation the photosensitizer becomes toxic to the targeted tissue. Several photosensitizer drugs are available today to treat specific cancers (such as skin, lung, brain, bladder, pancreas, bile duct, esophagus, and head and neck) and a variety of diseases including acne, psoriasis, and age- related macular degeneration.
There are multiple applications for lasers and light therapy in Dermatological treatments for psoriasis, vitiligo and eczema that include:
UVA and UVB Devices
A variety of light/lasers with different mechanisms of action have been developed for psoriasis including ultraviolet B (UVB), psoralen ultraviolet A (PUVA), pulsed dye laser (PDL), photodynamic therapy (PDT), intense pulsed light (IPL), and light-emitting diodes (LED). Psoriasis is an autoimmune inflammatory skin disease. In the past several decades, phototherapy has been widely used to treat stable psoriatic lesions including trunk, scalp, arms and legs, and partial nail psoriasis.
Excimer lasers aim a high intensity ultraviolet B (UVB) light dose of a very specific wavelength – 308 nanometers – directly at the psoriasis plaques. Because the laser light never touches the surrounding skin, it reduces the risk of UV radiation exposure. Excimer lasers are used to treat mild-to-moderate psoriasis. With excimer laser therapy, patients usually have 2 sessions a week for 4 to 10 sessions to achieve results.
Depression, Seasonal Affective Disorder, Circadian & Sleep Disorders, Jet Lag
Full Spectrum Lighting
Light therapy for SAD and sleep disorders use either a light box which emits up to 10,000 lux of light (Full Spectrum Lighting) at a specified distance, much brighter than a customary lamp, or a lower intensity of specific wavelengths of light from the blue (460nm) to the green (525nm) areas of the visible spectrum.
Neonatal Jaundice (Postnatal Jaundice)
Blue Light Fluorescent, LED or Fiberoptic Wraps
Light therapy is used to treat cases of neonatal jaundice caused by bilirubin. Bilirubin is most successful at absorbing light in the blue region of the visible light spectrum, which falls between 460 – 490nm. Light therapy technologies that utilize these blue wavelengths (including Fluorescent Bulbs, LED or Fiberoptic Wraps) are the most successful at isomerizing bilirubin.
The Illuminating History of Light Therapy from the Ancients to Einstein to 2020
Light has been recognized as a source of energy and healing since the early days of recorded time. Ancient Greeks, Romans and Egyptians practiced heliotherapy or healing by sunlight. In the 17th century, Sir Isaac Newton identified the visible spectrum of light when he separated light with a prism. Two hundred years later in 1917, Albert Einstein first explained the theory of stimulated emission. This theory became the basis of LASER or “Light Amplification by Stimulated Emission of Radiation.” During the 1940s – 1950s scientists and engineers did extensive work to realize a practical device based on the principle of stimulated emission, and in 1960 the first Laser was developed. By the end of the 1960s a Hungarian physician, Endre Mester, reported an improvement in the healing of wounds through non-ablative low-level laser radiation. He is credited as the discoverer of positive biological effects that was named cold laser or low-level laser therapy.
In the mid-1990s the FDA cleared the use of Light Emitting Diode (LED) pads for therapy, and in 2002 the FDA cleared the first lasers with therapeutic claims: Class III lasers in 2002 and Class IV lasers in 2003.
Today, light is used in a wide range of medicine from diagnostics to surgery, and from aesthetic procedures to rehabilitation and therapy. Understanding light better requires a brief look at the science behind its power and therapeutic promise.
The Science of Light
In physics, electromagnetic radiation is one of the many ways that energy travels through space and is a combination of electric and magnetic fields. These are classified and arranged by wavelength including the radio waves, microwaves, visible light, infrared and gamma rays of the electromagnetic spectrum.
The Electromagnetic Radiation Spectrum
Light is composed of photos that are small packets of light energy and classified on the electromagnetic radiation spectrum. Light travels at a constant speed, approximately 186,282 miles per second, and oscillates as it moves forward. However, all light is not the same. The property that differentiates light energy within the electromagnetic radiation spectrum is the wavelength, which is measured in nanometers (nm). The wavelength of light not only determines color in the visible spectrum, but also its depth of penetration into the body system.
Wavelengths of light within the visible spectrum are only a small fraction of the different types of radiation that exist. Visible light has a wavelength that ranges from 380nm – 750nm on the electromagnetic radiation spectrum. Infrared light is just beyond the visible wavelengths, ranging from 700nm – 1mm in a part of the non-visible portion of the spectrum. Infrared light cannot be seen except with special equipment like security or infrared cameras.
How Light Interacts with The Human Body: Photochemical Mechanism of Action
Light can interact with the body in several ways including:
1) photothermal or photoablation that uses heat to vaporize tissue and includes surgical lasers or hair removal lasers;
2) photomechanical or photoacoustic that breaks up the molecular bonds in tissue and includes tattoo removal lasers;
3) photochemical, photodynamic therapy or photobiomodulation that causes targeted cells to start light-induced chemical reactions and include therapy lasers and light devices.
When applied to an organism, light tuned to specific wavelengths and frequencies stimulates metabolic processes at the cellular level. Light therapy is therefore light that provides energy to cells of the body, which causes a series of chemical changes, and results in the body essentially healing itself.
Photobiomodulation (PBMT): The Correct Term for Red Light Therapy
Photobiomodulation Therapy (PBMT) is the application of therapeutic red light and near- infrared light to tissue that has been compromised by injury, disease or degeneration. This therapy has been clinically proven to reduce inflammation, support immune function, and stimulate cellular repair. The results are improved muscle performance, improved joint motion, enhanced wound healing and much more. It is safe, relaxing, and has no known negative side effects. In recent studies, photobiomodulation has demonstrated increased exercise capacity and longer exercise times, as well as improved biomarkers. These include reduced lactate, creatine kinase, and C-reactive protein (CRP) after exercise in people treated with red and infrared light. PBMT has a wide range of effects at the molecular, cellular, and tissular levels.
“PHOTO” means light. “BIO” means life. “MODULATION” means change.
According to the North American Association of Photobiomodulation Therapy (NAALT), Photobiomodulation Therapy is defined as “A form of light therapy that utilizes non-ionizing forms of light sources, including LASERS, LEDs, and broad-band light, in the visible and infrared spectrum. It is a non-thermal process involving endogenous chromophores eliciting photophysical (i.e. linear and non-linear) and photochemical events at various biological scales. This process results in beneficial therapeutic outcomes including but not limited to the alleviation of pain or inflammation, immunomodulation, and promotion of wound healing and tissue regeneration.”
The Photochemical Process of Photobiomodulation
Studies have shown that when tissue cultures are irradiated by light, enzymes within cells absorb energy from the light. Visible (red) light and Near-Infrared (NIR) are absorbed within the
mitochondria and the cell membrane. This produces higher ATP levels and boosts DNA production, leading to an increase in cellular health and energy.
Diagram showing the absorption of red or near-infrared (NIR) light by specific cellular chromophores or photoacceptors localized in the mitochondria. During this process, respiration chain ATP production will increase, reactive oxygen species (ROS) are generated, and nitric oxide is released or generated. These cytosolic responses may in turn induce transcriptional changes via activation of transcription factors (e.g. NF-κB and AP-1).
Summary of the Photochemical Process of Photobiomodulation
Absorbed in Mitochondria and Cell Membrane within Cytochromes and Porphyrins
Singlet Oxygen is Produced
Changes in Membrane Permeability
ATP Synthesized and DNA Produced
Increase in Cell Metabolism from a Depressed Rate to a Normal Level
Selective Bio-Stimulatory Effect on Impaired Cells (note: cells and tissues functioning normally are not affected)