The secret behind Theradome is the following. Light must be absorbed by a chromophore (which gives a molecule its color) to initiate a photochemical effect and to ultimately have a biological effect on hair. This is the first law of photochemistry. Light must hit this chromophore to prompt the engine of the cell, called the mitochondria, to start working again. If laser light is not 680-nanometers, the process of converting light energy into chemical energy to repair the hair follicle does not occur.