Zahler® - mind & spirit: l-tryptophan 500mg - 60 capsules purified l-tryptophan l-tryptophan is used by the brain as a precursor to serotonin and melatonin, neurotransmitters that are necessary for normal sleep. Adequate sleep is crucial for healthy immune and nervous system function. In addition, changes in the level of serotonin in the brain can impact mood and satiety. High potency serotonin enhancer non-gmo gluten, dairy, soy free vegetarian friendly kosher gmp certified these statements have not been evaluated by the food and drug administration. This product is not intended to diagnose, treat, cure, or prevent any disease. . Zahler l-tryptophan supplement (60 servings) healthy - 60 capsules