L-5-Hydroxytryptophan (5-HTP) is an amino acid synthesized in the body from tryptophan, which is found in dietary proteins and is used to make serotonin,an important brain chemical involved in mood, behaviour, appetite, and sleep. Serotonin production is affected by the age and lifestyle that people have. HealthAid's L-5-HTP helps support the production of this important substance for a healthy nerve and brain function.