It is the metabolic precursor of serotonin, the neurotransmitter best known for inducing feelings of calmness and drowsiness. Studies have shown that low tryptophan levels increase aggression, anger and depression, whereas high tryptophan levels have a therapeutic effect in pathologically aggressive patients and promote a feeling of well-being and elevated mood.
The transport of tryptophan across the blood-brain barrier depends on plasma concentrations of both tryptophan and other large neutral amino acids (LNAA; tyrosine, phenylalanine, leucine, isoleucine, and valine) as these compete for thesamecarriermechanism. A high postprandial level of insulin in blood after a carbohydrate load favors the transport of tryptophan to the brain because it mediates the uptake of LNAA into muscle but not tryptophan, which is largely bound to plasma albumin, thus increasing the tryptophan/LNAA ration in blood and favors the transport of the latter into the brain.
It is needed in the synthesis of serotonin from tryptophan by aromatic L-amino acid decarboxylase.
It suppresses the activity of tryptophan 2,3-dioxygenase, which is one of the key enzymes in the conversion of tryptophan to niacin. If tryptophan is converted to niacin, it wil not be available as a precursor of serotonin in the brain, and thus, supplementation with vitamin B3 can reduce the “loss” of tryptophan to nicotinic acid.
Trypsin hydrolyzate bovine casein
It is a bioactive peptide coming from the tryptic hydrolysis of αs1-casein presents in cow’smilk, which has affinity for GABA (γ-amino-butyricacid) receptors, exerting benzodiazepine-like effect. α-casozepine has been proven to improve reactions when interacting with strangers, signs linked to fear (including aggression), as well as neuro-vegetative signs, often linked to stress and anxiety.