NaturalNews) L-tryptophan is an essential amino acid that helps improve sleep and reduce stress. It acts as a precursor to many neurotransmitters and neurochemicals, including serotonin and melatonin. Melatonin is known to help improve sleep, and serotonin is needed to improve mood and mental health. Many antidepressants work by regulating the uptake of serotonin. With the stresses of today’s hectic world, many people are deficient in L-tryptophan. The amino acid is not found in the body so it must be added through foods of nutritional supplements.