Several studies, especially for vitiligo, show that LLLT exhibits stimulatory effects on pigmentation. the effects of blue light (415 + 5 nm, irradiance 40 mW/cm2, 48 J/cm2) and red light (633 + 6 nm, 80 mW/cm2, 96 J/cm2) in combination, yielded results where an overall decrease in melanin was observed (Lee et al., 2007b). Melanin levels increased by 6.7 arbitrary units in individuals after blue light irradiation, without a statistical significance (P-value > 0.1), whereas, they decreased by 15.5 arbitrary units, with a statistical significance (P-value < 0.005), following red light irradiation.
These findings may be associated with the ability of the laser to brighten the skin tone of the irradiated area, which was reported by 14 out of 24 subjects after the treatment period.