5-htp is a naturally occuring amino acid and is the direct precursor to serotonin and is taken for mood support. It works by increasing the cells output of serotonin. Recent studies have suggested not only is it helpful for depression, but also may be beneifical in helping your body to regulate appetite, sleeping problems, anxiety, and cognitive enhancement. Natural Factors enteric coats their 5htp for best absorption. Higher potency for therapeutic applications.