In general, red light therapy does not make hyperpigmentation worse. But there are exceptions and more research is needed in this area. Visible light (where red light is included) is shown to cause melanogenesis (leading to uneven pigmentation) as well as formation of free radicals in the skin. Even though this is most probably due to the blue light, there is a need to be cautious. As mentioned above in my review, I did personally experience a worsened melasma after using red light on my face (and I am not alone). Which made me stop using it.