LEDs offer a totally natural, non-ablative method for skin rejuvenation. The light from the LEDs interacts with cells and stimulates them to produce new collagen and elastin. bio light therapy.Studies confirm that the same LED energy can be used to inhibit collagen formation, which can be helpful in the treatment of scars. By manipulating the wavelengths, cells can be turned on and off. Yellow light LEDs are used for photo-rejuvenation. Blue light LEDs are used in the treatment of acne. Red light LEDs are used for PhotoDynamic therapy.