the year 2015

tryptophan

Tryptophan is an amino acid and essential in human nutrition. It is one of the 20 amino acids in the genetic code (codon UGG). Only the L-stereoisomer appears in mammalian protein.

Trp is a precursor for serotonin (a neurotransmitter), melatonin (a neurohormone), and niacin. The functional group of Trp is indole; see that article for more on its chemical properties.

Tryptophan has been implicated as a possible cause of schizophrenia in people who cannot metabolize it properly. When improperly metabolized it creates a waste product in the brain which is toxic and causes hallucinations and delusions. Trp has also been indicated as an aid for schizophrenic patients.

Trp, found as a component of dietary protein, is particularly plentiful in chocolate, oats, bananas, dried dates, milk, cottage cheese, fish, turkey, and peanuts.

In recent years, compounding pharmacies and some mail-order supplement retailers have begun selling Trp to the general public. Trp has also remained on the market as a prescription drug (Tryptan) which some psychiatrists continue to prescribe, particularly as an augmenting agent for people who are unresponsive to antidepressant drugs. Indeed, Trp has continued to be used in clinical and experimental studies employing human patients and subjects. Several of these studies suggest Trp can effectively treat the fall/winter depression variant of seasonal affective disorder (SAD).