Natrol 5-HTP 200 mg Time Release has a delivery system that releases 5-HTP slowly and then steadily over a period of time. 5-HTP is a drug-free, amino acid derived from a plant that naturally increases the body’s level of serotonin, the chemical messenger that affects emotions, behavior, appetite, thought and sleep. Today’s stress-filled lifestyles and dietary practices may negatively affect how the body handles serotonin. Regular use of Natrol 5-HTP helps promote a more positive outlook and greater appetite control.