Tryptophan is an essential amino acid that the body cannot produce on its own, meaning it must be obtained through diet. It plays a crucial role in the production of proteins and is a precursor to important substances like serotonin, a neurotransmitter that helps regulate mood, sleep, and appetite. Foods rich in tryptophan include turkey, chicken, dairy products, nuts, and seeds. Once consumed, tryptophan is converted into 5-hydroxytryptophan (5-HTP) and then into serotonin. This process can influence feelings of well-being and relaxation. While tryptophan is often associated with sleepiness, its effects depend on various factors, including overall diet and individual metabolism.