Red Light Therapy Glossary
Understand the science behind photobiomodulation. Clear, concise definitions of the key terms you need to know.
Adenosine Triphosphate (ATP)
Adenosine triphosphate (ATP) is the primary energy carrier molecule in all living cells. Red light therapy increases ATP production by stimulating mitochondrial function through photobiomodulation.
Read full definition →Angiogenesis
Angiogenesis is formation of new blood vessels from existing vasculature; PBM may stimulate it in wound healing.
Read full definition →BDNF (Brain-Derived Neurotrophic Factor)
BDNF is a protein supporting neuron survival and synaptic plasticity; PBM may upregulate it in some studies.
Read full definition →Beam Divergence
Beam divergence is how much an LED's light beam spreads with distance, affecting effective treatment area and intensity.
Read full definition →Biphasic Dose Response
The biphasic dose response (Arndt-Schulz curve) is a fundamental principle in photobiomodulation where low doses of light stimulate biological activity, but excessive doses inhibit it, creating an optimal therapeutic window.
Read full definition →Circadian Rhythm
Circadian rhythm is the body's roughly 24-hour internal clock regulating sleep, hormones, and tissue repair.
Read full definition →Collagen Cross-Linking
Collagen cross-linking refers to chemical bonds between collagen fibers that increase tissue tensile strength.
Read full definition →Complex IV / Electron Transport Chain
The electron transport chain is the final stage of cellular respiration; complex IV is cytochrome c oxidase, a primary PBM photoreceptor.
Read full definition →Cytochrome C Oxidase
Cytochrome c oxidase is an enzyme (Complex IV) in the mitochondrial electron transport chain that acts as the primary photoacceptor for red and near-infrared light, making it the key molecular target in photobiomodulation.
Read full definition →Cytokine Modulation
Cytokine modulation is adjustment of cytokine levels, or signaling proteins, via interventions like photobiomodulation.
Read full definition →Fibroblast
Fibroblasts are connective tissue cells that synthesize collagen and extracellular matrix during wound healing and skin remodeling.
Read full definition →Fluence (J/cm²)
Fluence is the measure of light energy delivered per unit area, expressed in joules per square centimeter (J/cm²). It is the standard dosimetric parameter used in photobiomodulation research to define treatment protocols.
Read full definition →IL-6 (Interleukin-6)
IL-6 is a cytokine involved in inflammation and immune signaling; reduced levels often indicate reduced inflammation.
Read full definition →Irradiance (mW/cm²)
Irradiance is the measure of optical power density delivered to a surface, expressed in milliwatts per square centimeter (mW/cm²). It determines how much light energy reaches your tissue at a given distance.
Read full definition →Irradiance Falloff
Irradiance falloff is the decrease in light intensity as distance from the LED source increases, following inverse-square behavior in open space.
Read full definition →LED Therapy
LED therapy is a form of photobiomodulation that uses light-emitting diodes (LEDs) to deliver specific wavelengths of light to the body for therapeutic purposes, including skin health, pain relief, and tissue repair.
Read full definition →Lymphatic Drainage
Lymphatic drainage is movement of lymphatic fluid through the body's lymph system, removing waste and supporting immune function.
Read full definition →Melatonin
Melatonin is a hormone produced by the pineal gland that regulates sleep cycles.
Read full definition →Mitochondrial Biogenesis
Mitochondrial biogenesis is the process by which cells create new mitochondria; it can be triggered by exercise and photobiomodulation.
Read full definition →Mitochondrial Membrane Potential
Mitochondrial membrane potential is the electrochemical gradient across the inner mitochondrial membrane essential for ATP production.
Read full definition →Myelination
Myelination is the process of forming an insulating sheath around nerve fibers; key to nervous system function.
Read full definition →Near-Infrared (NIR) Light Therapy
Near-infrared light therapy is the use of 700-1100nm wavelengths to penetrate deeper tissue for therapeutic effect.
Read full definition →Nitric Oxide Release
Nitric oxide release is PBM-induced dissociation of nitric oxide from cytochrome c oxidase, increasing oxygen utilization.
Read full definition →Optical Window
The optical window is the 600-1100nm wavelength range where tissue absorbs less light, allowing deeper therapeutic penetration.
Read full definition →Oxidative Stress
Oxidative stress is cellular damage caused by an imbalance between reactive oxygen species production and antioxidant defenses.
Read full definition →Peak Wavelength
Peak wavelength is the dominant wavelength emitted by an LED, measured in nanometers; it defines the therapeutic target range.
Read full definition →Photobiomodulation (PBM)
Photobiomodulation is the use of non-ionizing light sources, including lasers and LEDs, to stimulate cellular function and promote tissue repair through photochemical reactions in the mitochondria.
Read full definition →Photon Flux
Photon flux is the number of photons delivered per second per unit area; it is related to but distinct from irradiance.
Read full definition →Photoreceptor
A photoreceptor is a molecule or cell that absorbs light energy; in PBM, cytochrome c oxidase is a primary cellular photoreceptor.
Read full definition →Pulsing / PWM (Pulse Width Modulation)
Pulsing or PWM is on-off pulsing of LED output at controlled frequencies; some studies suggest pulse frequencies may affect PBM responses.
Read full definition →Red Light Therapy
Red light therapy is a non-invasive treatment that uses specific wavelengths of red and near-infrared light to promote cellular repair, reduce inflammation, and support overall health through photobiomodulation.
Read full definition →Retinal Photobiomodulation
Retinal photobiomodulation is application of red/NIR light to the eye; research suggests mitochondrial support for retinal cells.
Read full definition →ROS (Reactive Oxygen Species)
Reactive oxygen species are oxygen-containing molecules involved in cellular signaling at low doses and oxidative stress at high doses.
Read full definition →Tissue Penetration Depth
Tissue penetration depth is how deep light energy travels into tissue; longer NIR wavelengths penetrate deeper than shorter red wavelengths.
Read full definition →TNF-alpha
TNF-alpha is a pro-inflammatory cytokine modulated by photobiomodulation in some studies.
Read full definition →Transcranial NIR
Transcranial NIR is near-infrared light delivered through the skull to influence brain tissue; it is an emerging research area.
Read full definition →See the Science in Action
Hale RLPRO panels deliver clinically relevant wavelengths, irradiance, and dosing across the full therapeutic spectrum.