You will have come across the various names for the use of red and near infrared lights. Michael Hamblin, one of the lead researchers in the area, has summarised the terminology changes beautifully in a recent article called (somewhat dauntingly) Mechanisms and Mitochondrial Redox Signalling in Photobiomodulation. Click here to read the full article.
Low Level Laser Therapy (LLLT)
Almost 50 years ago in Hungary, Endre Mester found by accident, that a low power red laser noticeably improved wound healing.
It was initially thought that light delivered by a laser was the key factor in the wound healing, and so the term Low Level Laser Therapy, abbreviated to LLLT, was developed.
If you put “LLLT” in your favourite search engine, you’ll find a lot of references will pop up.
LED light
Once LED lights became available, it was found that light in laser form was not magical or special. The key was the wavelength. Whether from a LED light or a laser, the wavelength in the red to near infrared range was the critical factor.
Lasers need to be handled carefully, as they can be dangerous, whereas LEDs are safe to use, and they can be easily made into a variety of wavelengths. LED development has been a game changer.
As research into lights continued, it was realised that the term Low Level Laser Therapy was problematic because:
- ‘Nobody had any idea exactly what “low-level” meant’. (Hamblin’s own words).
- LED lights were being used more and more in place of lasers.
- The discovery that, depending on the “dose”, red lights can have a positive effect and not so positive effect. (See the post on the Goldilocks effect).
In 2016, there was an international agreement to change the terminology.
Photobiomodulation (PBM)
The term LLLT was abandoned and the term Photobiomodulation was adopted. And of course, it was immediately abbreviated to PBM.
When you return to your search engine, you will find different articles pop up for “Photobiomodulation” and for “PBM”.
I’ll return to this article in future posts as it has more interesting stuff.
Red lights on the brain 