Red Light Basics
Understanding 660 nm and 850 nm Red Light
660 nm is visible red light, while 850 nm is near-infrared light and is much less visible to the eye. Both sit within wavelength ranges commonly studied in photobiomodulation, but wavelength alone does not establish dose, penetration, safety, or a health outcome. Device power, distance, contact, session time, and the research protocol still matter.
01
Visible red and near-infrared
Nanometers describe wavelength. Light around 660 nm appears red to the human eye. Light around 850 nm is near-infrared, so the LEDs may look dim or partly unlit even when near-infrared output is active.
That visual difference does not tell you the delivered dose. Brightness to the eye is not a substitute for measured optical output.
02
Wavelength is not a complete protocol
Research protocols combine wavelength with power density, energy density, exposure time, treatment frequency, application distance, and a defined target. Changing any of those variables can change how closely one study resembles another.
This is why a wavelength match between a paper and a consumer device is only a starting point for comparison, not product-specific proof.
03
What is confirmed for the rePretty Mat
The current rePretty Mat uses 660 nm and 850 nm LEDs. It also has constant, 10 Hz, and 40 Hz modes, five levels, and a 10 to 90 minute timer.
Because a public irradiance report is not yet part of the approved fact set, rePretty does not publish a research-derived dose claim for the mat. Follow the product instructions rather than reverse-engineering a protocol from an unrelated paper.
Source notes
Sources
- 01Proposed Mechanisms of Photobiomodulation or Low-Level Light Therapy
Discusses commonly used red and near-infrared wavelength ranges
- 02Mechanisms and Applications of the Anti-Inflammatory Effects of Photobiomodulation
Category-level wavelength and dose discussion
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