5-HTP is an amino acid produced by the human body from the essential amino acid L-tryptophan (LT), which is found in dietary proteins. It's clinical value is in it's ability to increase production of serotonin, and it has been use clinically for more than 30 years. 5-HTP occurs naturally in two places -- the human body and the seeds of the Griffonia Simplicifolia, a West African medicinal plant.