SOURCE NATURALS - L-Tryptophan 500 mg - 120 TabletsDESCRIPTION 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, brain chemicals 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