Red light exposure can have phototherapeutic effects on skin cells and other biological cells and tissues affected by UV damage. However, existing methods and devices using red light in DNA phototherapy have not identified the proper duration, intensity, or delivery mechanisms for optimal DNA repair. If the radiant intensity of the red light is too low, then exposure is inadequate and the repair biomarkers are not activated. Conversely, prolonged exposure to excessive electromagnetic radiation only furthers DNA damage. Moreover, in the context of skin treatment, excessive radiant intensity can burn tissue or have carcinogenic side effects. Thus, there is a need for a device and methods of use that provide safe, effective, and targeted red light DNA phototherapy.