Economy Size Naturally Sourced Non-GMO Soy Free Supports a Positive Mood Vegetarian Formula Dietary Supplement Healthy Origins 5-HTP (5-Hydroxytryptophan) is a naturally occurring substance extracted from the seeds of the Griffonia Simplicifolia plant. 5-HTP is a precursor to serotonin which is a vital neurotransmitter in the body. Serotonin is one of the primary neurotransmitters which supports healthy mood, appetite, and sleep. Healthy Origins 5-HTP is guaranteed to be free of the "peak x" contaminant.