Light and photobiomodulation
Photobiomodulation (PBM)
Photobiomodulation (PBM) is the use of red or near infrared light, at intensities too low to heat or damage tissue, to produce a change in how cells behave. It is the agreed scientific name for what used to be called low-level laser or light (LLLT), and it depends on wavelength, intensity and total dose.
Also called PBM, photobiomodulation therapy, PBMT, red light therapy
The everyday meaning. Shining a particular colour of light on the body, at a level you would describe as bright rather than hot, in the expectation that cells respond to it. The light is not cutting, burning or ablating anything; if it were, that would be a surgical or aesthetic laser, not photobiomodulation.
The term itself. “Photobiomodulation” replaced the older and vaguer name, LLLT. Anders, Lanzafame and Arany set out the case in Photomedicine and Laser Surgery (2015): “low-level” was undefined, the effect is not specific to lasers, and “modulation” is more accurate than “stimulation” because light can raise or lower a cellular activity depending on dose. PBM is now the preferred indexing term.
What is proposed to happen. Light in roughly the 600–1000 nm window is absorbed by molecules inside the cell, most often cytochrome c oxidase in the mitochondrion, and the downstream result is described as changed ATP output, changed reactive oxygen species signalling and changed gene expression. That is a mechanism supported by cell work rather than a demonstrated clinical outcome in a person.
Where to read more. Our red light and near infrared studies pages collect the literature and link on to the sources, which carry the full citations.
Reading a study against a device. A finding transfers only if the device delivers a comparable wavelength at a comparable irradiance and distance for a comparable time. Wavelength alone is not enough to match a study to a machine.
Why it matters here
PBM is the umbrella term for what the LEDs in the Red Light ozone sauna are there to do. If you are weighing that sauna against a standalone red light panel, this is the thing the two have in common.