Reply To: Does RLT have side effects? Home › Forums › Red Light Therapy › Does RLT have side effects? › Reply To: Does RLT have side effects? September 28, 2020 at 8:55 pm #749 MarianneParticipant You should know your body and skin type and check if light therapy is good and suitable for your type. Some lights if not used properly and with care might leave a red mark or burn you.