Light therapy, Photobiomodulation, LLLT, phototherapy, infrared therapy, red light therapy and so on, are different names for similar things – applying light in the 600nm-1000nm range to the body. Many people swear by light therapy from LEDs, while others will use low level lasers. Whatever the light source, some people notice tremendous results, while others might not notice much at all.
The most common reason for this discrepancy is a lack of knowledge about dose. To be successful with light therapy, you first need to know how strong your light is (at different distances), and then how long to use it for.
Is there more to light therapy dosing?
While the information laid out here is adequate to measure dose and calculate application time for general use, light therapy dosing is a much more complicated matter, scientifically.
J/cm² is how everyone measures dose now, however, the body is 3 dimensional. Dose can also be measured in J/cm³, which is how much energy is applied to a volume of cells, rather than just applied the surface area of skin.
Is J/cm² (or ³) even a good way to measure dose? A 1 J/cm² dose can be applied to 5cm² of skin, while the same 1 J/cm² dose could be applied to 50cm² of skin. The dose per area of skin is the same (1J & 1J) in each case, but the total energy applied (5J vs 50J) is vastly different, potentially leading to different systemic outcomes.
Different strengths of light can have different effects. We know that the following strength and time combinations give the same total dose, but the results wouldn’t necessarily be the same in studies:
2mW/cm² x 500secs = 1J/cm²
500mW/cm² x 2secs = 1J/cm²
Session frequency. How often should sessions of ideal doses be applied? This may be different for different issues. Somewhere between 2x per week and 14x per week is shown effective in studies.
Summary
Using the right dose is key to get the most out of light therapy. Higher doses are required to stimulate deeper tissue than for the skin. To calculate dose for yourself, with any device, you need to:
Figure out your light’s power density (in mW/cm²) by measuring it at different distances with a solar power meter.
If you have one of our products, use the table above.
Calculate dose with the formula: Power Density x Time = Dose
Look for dosing protocols (strength, session time, dose, frequency) that have been proven effective in relevant light therapy studies.
For general use and maintenance, between 1 and 60J/cm² may be appropriate