L-tryptophan is an essential amino acid that plays an important role in the body’s production of serotonin, a neurotransmitter that affects mood and sleep. It is found naturally in foods such as meat, fish, dairy products and nuts, but it can also be taken as a dietary supplement. Many people use L-tryptophan supplements to support healthy sleep, improve mood balance and promote feelings of relaxation. It is popular among those looking for natural ways to support their mental and emotional well-being.