The best time for children to take lysine is before bedtime or between meals, depending on the individual case and according to medical advice. Lysine is one of the essential amino acids that promote human development and has a brain-boosting effect, and can enhance immune function. The best bioavailability is achieved when lysine is taken after lunch and before dinner, i.e. between 4 and 5 pm. Because the gastrointestinal tract is basically empty at this time, lysine can be taken for maximum digestion and absorption. However, if the child has gastrointestinal disorders, lysine should not be taken on an empty stomach to avoid nausea and vomiting. Therefore, if necessary, parents are advised to bring their children to the pediatric internal medicine department of a regular hospital to have them examined by a professional doctor and then develop an individualized treatment plan.