Best Naturals, L-Tryptophan, 500 mg, 120 CapsProduct Description L Tryptophan is an essential amino acid; therefore, it is not synthesized by the body and must be obtained from the diet. L Tryptophan is critical for the production of serotonin and melatonin, which help to support a positive mood, healthy sleep patterns, and proper immune system function. Product Benefits Supports Healthy Nervous System Supports Circulation & Positive Mood Supports Relaxation & Restful Sleep Supports Healthy