From the Manufacturer:
L-Tryptophan is an essential amino acid that is converted into 5-L-Hydroxytryptophan (5-HTP) in the body. 5-HTP is then converted into serotonin and melatonin. Normal serotonin levels have been associated with normal moods, appropriate appetite and weight maintenance, and proper sleep.* Our 5-HTP is derived from a plant source, and is carefully tested to ensure its purity and to guarantee the absence of contaminants.