The red light therapy world is full of technical jargon — wavelengths, irradiance, photobiomodulation, cytochrome c oxidase. This glossary defines the 30 most common terms so you can make informed decisions.
A–H
- ATP (Adenosine Triphosphate)
- The energy currency of cells. RLT boosts ATP production in mitochondria.
- Biphasic Dose Response
- The phenomenon where too much RLT produces fewer results than the optimal dose. More isn't better.
- Blue Light (415nm)
- Visible light wavelength that kills acne-causing bacteria. Often combined with red light in acne devices.
- Cold Laser Therapy
- Another name for LLLT (Low-Level Laser Therapy).
- Cytochrome C Oxidase (CCO)
- The mitochondrial enzyme that absorbs red/NIR light. The primary photoacceptor in RLT.
- Dermis
- The deeper layer of skin where collagen is produced. 660nm light penetrates to this layer.
- FDA-Cleared
- Means the FDA reviewed safety data through the 510(k) process. Stronger than "FDA-listed."
- FDA-Listed
- Means the manufacturer registered the device with the FDA. Weaker than "FDA-cleared."
- Fibroblast
- The skin cell that produces collagen. RLT stimulates fibroblast activity.
- Galvanic Current
- Low-level electrical current used in some wand devices (like Solawave) to enhance skincare absorption.
I–P
- Infrared Sauna
- Sauna using far-infrared light (3000nm+) for heat therapy. Different from RLT.
- IPL (Intense Pulsed Light)
- High-intensity pulsed light used for hair removal and pigmentation. Different from RLT.
- Joule (J)
- Unit of energy. RLT dose is measured in J/cm² (joules per square centimeter).
- LED (Light-Emitting Diode)
- The light source used in most at-home RLT devices.
- LLLT (Low-Level Laser Therapy)
- Another name for RLT, especially when used for hair regrowth. Uses lasers instead of LEDs.
- Lumens
- Measure of visible light brightness. Not the same as irradiance — a bright light can have low therapeutic irradiance.
- Mitochondria
- The "power plants" of cells that produce ATP. The primary target of RLT.
- Nanometer (nm)
- Unit of wavelength. RLT uses 600–1000nm wavelengths.
- Near-Infrared (NIR)
- Light in the 800–1000nm range. Penetrates deeper than red light (5–10mm vs 2–5mm).
- Nitric Oxide (NO)
- A signaling molecule released during RLT that dilates blood vessels, improving circulation.
- Photobiomodulation (PBM)
- The scientific name for red light therapy. Literally "light modifying biology."
R–Z
- Red Light (630–700nm)
- Visible red light that penetrates 2–5mm into skin. Used for collagen stimulation and surface inflammation.
- RLT
- Abbreviation for Red Light Therapy.
- Spectrometer
- Device used to measure light wavelengths. Reputable RLT brands publish third-party spectrometer reports.
- UV (Ultraviolet)
- Light below 400nm that damages DNA and causes cancer. NOT used in RLT.
- Visible Light
- Light in the 380–750nm range that humans can see. Red light (630–700nm) is visible.
- Wavelength
- The distance between successive peaks of a light wave, measured in nanometers. Determines the light's properties.
Frequently Asked Questions
Literally "light modifying biology." It's the scientific name for red light therapy.
Same thing. LLLT (Low-Level Laser Therapy) is the older term, often used for hair regrowth. RLT is the broader term.
The phenomenon where too much RLT produces fewer results than the optimal dose. More isn't better with RLT.
FDA-cleared means the FDA reviewed safety data through the 510(k) process. FDA-listed just means the manufacturer registered the device. Cleared is stronger.
Irradiance is the power density of light, measured in mW/cm². Higher irradiance means faster therapeutic doses. The most important spec after wavelengths.
Red light (630–700nm) penetrates 2–5mm for skin concerns. Near-infrared (800–1000nm) penetrates 5–10mm for muscle and joint issues.
Apply What You Learned
The MitoMAX 2.0 hits all the right specs — 660nm + 850nm, 110 mW/cm², FDA-cleared brand.
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