KN-8000A, 650NM cold laser devices that emit low power coherent monochromatic red light developed for hair growth. 

650NM laser penetrate to the depth of the superficial and mid-derma where hair follicle distributed and most of energy focused on and absorbed by the hair follicals without the attenuation of energy, stimulate the follicle and strengthen the root of hair.

Hair follicles  rich in melanin, and melanin can specifically absorb LLLT soft laser. The experiment confirmed that adequate absorption of energy by hair follicles, protein synthesis accelerated,  dilated capillary conducive to the absorption of nutrients and oxygen from the bloods, and achieving the growth of hair.

Low level laser radiation acts on the mitochondria and may alter cell metabolism, causing increased ATP production, modulation of reactive oxygen species, and induction of transcription factors. These transcription factors in return cause protein synthesis that triggers further effects down-stream, such as increased cell proliferation and migration, alteration in the levels of cytokines, growth factors and inflammatory mediators, and increased tissue oxygenation.