Red Light Therapy Questions Part 1: Devices, Wavelengths and Infrared Light Explained
Red light therapy (PBM) tends to raise the same questions time and again. That is why we are dedicating this series to the topics we hear about most. In this first part, we cover red light therapy devices, whether more wavelengths are actually better, why some LEDs appear to not be working, and the difference between red light therapy and other forms of infrared light.
We also look at the differences between Vivo models. If your question is not covered here, visit our full FAQ page for more information.
Questions About Devices and Technology
It looks like some of the lights are not on. Is that normal?
The short answer: yes, completely normal. Near-infrared LEDs are barely visible because near-infrared light falls outside the visible spectrum. Wavelengths like 810, 830, 850 and 1060 nm are virtually invisible to the naked eye, even though they are working perfectly.
Our panels combine visible red light with near-infrared light (NIR). The human eye perceives light in roughly the 380 to 780 nanometer (nm) range. Red light sits around 620 to 750 nm and is clearly visible. Near-infrared starts just above that range and is almost entirely invisible to us.
Depending on the model, Vivo panels use visible red wavelengths such as 630 nm, 660 nm and 670 nm, alongside near-infrared wavelengths such as 810 nm, 830 nm, 850 nm and, in some models, 1060 nm. This is why the red LEDs glow visibly while the NIR LEDs appear dim or even completely off, despite being fully active.
A simple way to think about it: a classic TV remote uses invisible near-infrared light around 940 nm. You cannot see it, but the signal is there and works just fine. The near-infrared LEDs in a red light panel work in exactly the same way. Invisible does not mean absent.
Red light is primarily associated with more superficial applications, while near-infrared penetrates deeper into tissue. That said, there is significant overlap in how they work, which is precisely why the two are so often combined in a single panel.
How deeply the light penetrates depends on a number of factors, including wavelength, light intensity, distance from the body, and the type of tissue being treated.
In a darkened room, you may notice a faint reddish or purple glow from the NIR LEDs. A phone camera can often detect near-infrared more clearly than the naked eye, though this varies by device, making it a useful way to check whether your NIR LEDs are active.