5-HTP is short for 5-Hydroxytryptophan, which is an amino acid. As a transitional component in tryptophan metabolism, 5-HTP is also a compound which in the metabolic pathway precedes the monoamine neurotransmitter serotonin. As a dietary supplement, 5-HTP is suggested for use as an antidepressant, sleeping aid, but also as an appetite suppressant. Vitamin B6 helps 5-HTP decarboxylate into serotonin, with assistance of a lyase enzyme, namely the aromatic L amino acid decarboxylase. The theory is that 5-HTP, when ingested as a supplement, leads to increased serotonin production. While mainly being used as an appetite suppressant in the body building community, it also improves cognitive abilities, but also endurance and stamina. While there are some concerns in use of 5-HTP and MAO inhibitors in combination, sensitive users report only positive effects, that is why it was included in Biochem 5-HTP.