SOURCE NATURALS - Serene Science L-Tryptophan 500 mg - 120 CapsulesDESCRIPTION Positive Mood The essential amino acid L tryptophan is the precursor for the synthesis of both melatonin and serotonin, a hormone and a neurotransmitter involved with mood and stress response and sleep wake cycles. It helps support relaxation, restful sleep, and positive mood. If needed, l tryptophan converts to niacin in the body, an important B vitamin. Source Naturals L Tryptophan is extremely pure and is regularly tested to ensure the