is tryptophan an indispensable amino acid
Description. Tryptophan is an essential amino acid. This means that it must be obtained through the diet in adequate quantities to meet the body's needs. Tryptophan is a precursor in the central nervous system of the neurotransmitter serotonin.Serotonin modulates mood and sleep patterns.escription. Tryptophan is an essential amino acid. This means that it must be obtained through the diet in adequate quantities to meet the body's needs. Tryptophan is a precursor in the central nervous system of the neurotransmitter serotonin.