SOURCE NATURALS - L-Tryptophan 500 mg - 120 CapsulesDESCRIPTION The essential amino acid L Tryptophan helps support relaxation, restful sleep, and feeling better. It plays a part in the synthesis of both melatonin and serotonin, hormones involved with mood and stress response. L Tryptophan also supports immune functions because it is the body??? s precursor to the kynurenines that regulate immunity. If needed, L Tryptophan converts to niacin in the body, which supports circulation, a healthy nervous