Natrol 5-HTP Time Release is a plant-derived source of an amino acid that naturally increases the body's level of serotonin, the chemical messenger that affects emotions, behavior, appetite, thought and sleep. Regular use of Natrol 5-HTP helps provide a more positive outlook, promotes relaxation & calm, and greater appetite control. Natrol 5-HTP TR is 100% vegetarian and has a controlled delivery system that releases 5-HTP slowly and then steadily over a period of 12 hours. Want to hear more? Check out customer-created Natrol 5-HTP Time Release reviews below!