Tryptophan

L-Tryptophan is an essential amino acid, meaning the human body cannot produce it and must obtain it through diet or supplementation. It is found naturally in protein-rich foods like turkey, seeds, and dairy. As a fundamental building block for protein synthesis, it is uniquely critical because it serves as the sole precursor to the neurotransmitter serotonin and the sleep-regulating hormone melatonin. Modern research also highlights its role as a precursor to niacin (Vitamin B3) and various metabolites in the kynurenine pathway that influence immune function.