HealthWise® L-Tryptophan is 100% pure pharmaceutical grade amino acid. This essential amino acid is found in all animal proteins and is often lacking in a vegan diet. L-Tryptophan and the conversion to 5-HTP are known precursors to enhance the neurotransmitter Serotonin, manufactured in the brain and GI tract. L-Tryptophan absorption can be boosted by supplementation with B group vitamins. Tryptophan is an essential amino acid. It is the precursor to 5-hydroxytryptophan (5-HTP) which is the direct precursor to serotonin. Serotonin is important for mood and sleep; when it is deficient, this can lead to anxiety, depression, insomnia and various other neuropsychological conditions. L-Tryptophan works in about 50% of insomnia cases. Tryptophan is the precursor for vitamin B3 in the form of nicotinamide adenine dinucleotide (NAD). Only about 1/60th of the tryptophan in the body is actually converted to NAD. Did you know? Enjoy your pasta. Carbohydrates also increase your serotonin levels, which help you to feel better and manage your appetite. Viva Italia!