5-HTP (5-Hydroxytryptophan) is another form of L-tryptophan, which also makes the neurotransmitter serotonin. 5-HTP can also be produced from the seeds of the plant, Griffonia simplicifolia. 5-HTP increases levels of Serotonin which promotes calmness and is therefore used to manage such disorders as insomnia, depression, anxiety, tension headaches, as well as ADHD, seizure disorders and Parkinson’s Disease.