5-HTP is the intermediate precursor in the natural synthesis of serotonin, a neurotransmitter that helps to regulate mood, appetite, and sleep/wake cycles.* 5-HTP readily crosses the blood-brain barrier and clinical studies suggest that 5-HTP can support healthy serotonin levels.* Serotonin is associated with a positive mood and provides a substrate for the production of melatonin.* 5-HTP is extracted from the bean of the African plant Griffonia simplicifolia, a natural vegetable source.