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Laser light generated by low-powered cold lasers has recently come into use as a non-surgical hair restoration treatment for pattern hair loss. 

Lasers have been used in the medical field for years. Use of laser light as a hair replacement therapy for treatment of hereditary hair loss, however, is a newer application of laser technology.


The “cold” lasers used as a hair replacement therapy deliver what is called low-level laser therapy (LLLT). The LLLT lasers are called “cold” because their light is absorbed by target tissue, but does not heat the target tissue as occurs with lasers used to cut and remodel tissue.


The Mechanics of a Laser
The laser is a device that produces and emits light of a very specific wavelength and power (wattage). The characteristics of wavelengths are what make laser unique. The color of laser light and the wattage are selected for specific purposes. For example, lasers that emit narrow wavelengths of green, red, infrared, etc., are selected and paired with appropriate power for specific purposes. The laser light used for treatment of pattern hair loss is visible red light with a wavelength of 630-670 nanometers, and low power (wattage).


LLLT in Hair Restoration: How It Works
Why is visible red light in the narrow spectrum of 630-670 nanometers and low power crucial for treatment of pattern hair loss? The answer is: because red light in that narrow spectrum at low power is absorbed by hair follicle molecules that are critical to stimulating hair growth or regrowth. Absorption of light by the hair follicle molecules is essential in order for a biological reaction to be stimulated in the molecules. If light is not absorbed, no reaction will occur.


An accidental observation in laboratory mice in 1967 led to the discovery that visible red laser light stimulates hair growth. A Hungarian scientist investigating the effect of laser light in treating skin cancer noticed that hair grew back more quickly on the skin of shaved mice treated with visible red laser light.


Research has shown that visible red laser light in the 630-670 nanometer spectrum is absorbed by an enzyme called cytochrome c. Photobiological reactions stimulated in cytochrome c send signals throughout cells of the hair follicle, stimulating enhanced gene activity, decreased gene-regulated cell death, and other changes that enhance cell activity and survival.


LLLT does not stimulate hair regrowth in every person. If molecules are unable to absorb laser light, or unable to adequately respond to absorbed light, no stimulation of hair regrowth will occur.


Experience has shown that stimulation of hair regrowth by LLLT is more likely to occur when hair loss is minimal to moderate.


Physicians who use LLLT in a treatment plan for a patient’s pattern hair loss have often noted it is more effective when used with other medical therapies such as hair restoration medicines.


Some physician hair restoration specialists have reported that LLLT may enhance hair growth and reduce inflammation after hair transplantation. LLLT is not a “one time only” treatment for pattern hair loss. As with other medical therapies, treatment must be repeated at intervals to maintain hair regrowth results.


The ISHRS takes no official stand on LLLT as a treatment for hair loss. On the one hand, it recognizes that some members strongly believe in LLLT as a complement to other treatments. On the other hand, the ISHRS is aware that there is currently a lack of good support from large, well-designed double-blind studies to support the effectiveness of LLLT as a treatment for hair loss.

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