NOW Foods, L-Tryptophan, Double StrengthDescription Experience deep relaxation with NOW Foods L Tryptophan Double Strength, a potent mood enhancing amino acid. NOW Foods L Tryptophan Double Strength is a non GMO, vegetarian vegan, and kosher dietary supplement that provides a higher dose of this essential amino acid to support relaxation, positive mood, and restful sleep. L Tryptophan is critical for the production of serotonin and melatonin, neurotransmitters that help regulate mood, sleep