Pattern hair loss, also called androgenetic alopecia, affects half of the men aged 50 years or older and more than half of the women aged 80 years or older.
Red light
The design of devices and the technology of home-use LLLT range from 620 to 678nm (visible red light).
FDA approved home-use devices for Low Level Light Therapy significantly increase hair density in pattern hair loss patients. These devices could improve hair density in both men and women, with no significant difference between the two sexes. Additionally, both the helmet/cap type and the comb type devices yielded effective treatment outcomes, yet with a significant difference between light and laser sources.
When considering the number of diodes, the comb-type devices used the least number of diodes, ranging from 7 to 12 diodes. The prices of comb type devices were lower. Hence, they could be good options for patients with financial limitations.
However, the noncoherent light sources, such as LEDs and broad-band lamps, have become more prevalent, with advantages of LEDs, including no laser safety issues, ease of home use, ability to irradiate a large area of tissue at once, wearability, and much lower cost per mW.
The mean change for hair diameter was 6.11±2.15μm in the laser group versus 3.76±1.24μm in the sham group. Therefore, the LEDs were as likely to impact photobiomodulation as the LDs.
Due to the very low power of LEDs (0.5mW/diode), compared to the appropriate dose of 2 to 4J/cm2, the results of LEDs could not be obviously concluded. Nevertheless, some head-to-head studies, which compared both light sources, yielded no difference in their effects. Hence, more high-quality head-to-head comparison studies are required to verify the significant difference between dose responses or physiological effects of LEDs and laser PBM.
The efficacy of LLLT appears comparable to the conventional PHL treatment with oral finasteride and topical minoxidil. The combination treatment of 5% minoxidil and LLLT appeared to provide a better response of hair density than minoxidil or LLLT alone.
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