Depending on the color of visible light it can penetrate the skin to different depths.
You may have played with a simple torch when you were a child. Placing it with a red bulb installed on your palm, you could see it shining through on the other side, and sometimes you could even see your bones, Yikes!!! But do the same with a blue light and nothing, no light penetrates. Pretty boring actually!! That’s because the two different colors have distinct properties. The colors can penetrate the skin to different depths.
This really is one of the fundamentals of light therapy. So light can penetrate our body to different depths, and then what!
We all know the effects of sunlight on our skin. That’s UV light, and it can cause significant changes. We can’t see the light, but we can see the changes it makes. A sun tan, which is nice. Freckles, which can be cute. But sun burn, we’ve all had that, and it’s not nice and not cute. All this and just from light.
Red light can cause significant changes too, but it is safe, no burning at this wavelength. It penetrates the skin deeper than the sun’s UV light, and it produces rejuvenating changes to the deeper cells and skin tissues. Fortunately they are all positive changes.
Red light can effectively penetrate the skin to a depth of between 610mm. When it is allowed to shine on the skin for a period of time is when the magic happens.