Jarrow Formulas® 5-HTP (5-Hydroxytryptophan) is derived from the Griffonia simplicifolia plant, found in West Africa. Using HPLC technology, we guarantee the highest possible purity. 5-HTP is the direct antecedent of serotonin and is essential for the production of melatonin, a hormone secreted by the pineal gland which assists the body's natural rhythms.*