5-Hydroxytryptophan, also known as 5-HTP, is a dietary supplement made from the seeds of the African plant Griffonia simplicifolia.5-HTP has been used in alternative medicine as a possibly effective aid in treating depression or fibromyalgia.5-HTP is an amino acid. Amino acids are substances that build proteins in your body. 5-HTP is related to serotonin, a brain chemical that affects mood, sleep, and pain.