A recent article compared the action of visible red 660nm with near-infrared 980nm.
The 660nm wavelength is a very lovely and rich shade of red, very much like the red velvet in Gwen’s photo of theatre curtains. In contrast, the wavelength 980nm is way out of the visible range and our eyes cannot see it at all.
This study showed that both wavelengths stimulated the cells into action through the mitochondria, the powerhouses inside cells. When the 980nm wavelength was used, it quickly stimulated the cell, but the effect died away pretty quickly.
In contrast, the visible red 660nm was slower to get going, but the effect lasted for at least 24 hours.
What does this finding mean?
Remember that mitochondria are like batteries, powering the cell to keep it healthy and active. The longer the mitochondrial batteries remain powered up, the longer the cell will function and – very importantly – the longer it will live.
Visible red 660nm, a rich colour to our eyes, is also a rich source of energy for our cells, and the energy that this wavelength generates will last for well over a day.
There has been interest in the use of longer wavelengths (900-1100nm) for light hats. This research article strongly suggests that it would be better to stick to visible red wavelengths.
Fuchs, Christiane, Merle Sophie Schenk, Linh Pham, Lian Cui, Richard Rox Anderson, and Joshua Tam. “Photobiomodulation Response From 660 Nm Is Different and More Durable Than That From 980 Nm.” Lasers in Surgery and Medicine 53, no. 9 (November 1, 2021): 1279–93.