With some Neurofeedback systems it is possible to experience side effects such as irritability or anxiety, headaches, and/or a sense of mental dullness. However, those types of side effects occur most commonly with certain systems involving customized protocols. Brain Prodigy Inc. uses a dynamical Neurofeedback system (Neuroptimal) where the algorithms and protocols are set, well researched and adjusted over the last 13 years to eliminate such side effects. Some people do feel relaxed and sleepy for a short time after a session. This does not necessarily occur after every session.