What is the best red light therapy wavelength? If you have begun your research into low-level light therapy (LLLT) then you have probably come across terms such as “wavelength” and “irradiance”. In this post, we’ll try to explain what they mean and what you need to know to continue your journey.
Wavelength is the Color (Kind of)
If you think back to one of your science classes, you may remember learning about the electromagnetic spectrum. Generally, electromagnetism is the science of how charged particles move in waves through space. This science covers all kinds of waves, including x-rays, gamma rays, and radio waves. But specifically, we focus on small portion called the “visible light spectrum”.
You Can See Some Wavelengths
Obviously the visible light spectrum is the small portion of electromagnetic waves that humans can see with our eyes. For example, these are the colors of the rainbow and all of the shades in between.
Just outside each end of the visible light portion of the spectrum lies ultraviolet light and infrared light.
Wavelength is a measure of distance between the peaks of the waves. We measure visible light in nanometers (nm). So a nanometer is one-billionth of a meter.
The human eye can detect wavelengths as small as 400nm and as large as 700nm.
Why is Wavelength Important for Treatment?
We all know that x-rays can penetrate many kinds of human tissue. That’s how they are used to “see” things on film. The harder, denser tissue absorbs or reflects some of those waves, while the softer tissue transfers those waves.
Most light works in a similar way. Body tissue reflects some colors, such as the shorter wavelengths. Certain parts of the body transfer the energy of some colors. Finally some “colors” are absorbed.
It turns out that some “colors” that are absorbed are exactly the ones that cause mitochondria in cells to produce the energy-storing chemicals that stimulate healing activities.
We’ve found clinical trials published online that have involved testing red light therapies with wavelengths of as low as 570nm and as high as 850nm. The specific wavelength selected for treatment depends primarily on the level of tissue penetration desired, with higher wavelengths penetrating deeper into human tissue. Wavelengths below 540nm, which is generally greenish light, will typically not penetrate more than 3 millimeters into skin. This depth is roughly equivalent to where the base of a hair follicle would be. Near-infrared, which has wavelengths of 750nm or greater, travels through skin. Higher wavelengths can reach bone and tissue deep inside the body.
Irradiance: the Intensity of the Energy Delivered to An Area
The light’s energy intensity is another important factor in understanding photobiomodulation (PBM). This measurement is written as Milliwatts per square centimeter (mw/cm2).
Total Exposure Matters Most
However, imagine this example. You’ve step outside in the desert sun in the middle of summer. Obviously the sun there is hot. But being outside for a few seconds won’t have a large effect on your body. Prolonged exposure to that kind of energy makes all the difference. A Joule is the amount of work required to produce one Watt of power for one second. You can measure the total energy delivered to an area in Joules. Your treatment will be more effective with more exposure to a constant light energy source.
Red Light Therapy Wavelength and Irradiance Determine the Best Dosage
Commercially-available devices are limited in how powerful they are. Devices that are designed for clinical environments with high concentrations, such as lasers, can be 80 times as powerful as an at-home, LED style red light therapy device.
You should carefully evaluate the health outcomes you seek and match your purchase decisions to the products that are capable of achieving those outcomes. Most products allow you to select the desired red light therapy wavelength.
Smaller, handheld products deliver less energy to an area of the body. Larger units, like beds or panels, deliver more energy.
If you’re treating small areas of skin or a single bone or joint, a smaller unit may work just fine. However, a handheld device might not work that well if you’re trying to cover a large portion of your body.
In our opinion, you should gather many opinions from multiple sources to ensure success. Peers and medical experts are great sources of advice. Overall, the cost of these innovative products is coming down. Most importantly, choose the product that best fits the wellness outcome that you’re seeking.