L-tryptophan 500mg- 90 CapsulesL Tryptophan is an essential alpha amino acid that is a precursor to the neurotransmitters serotonin and melatonin. Supplementation with tryptophan has been shown in numerous clinical trials to be safe, well tolerated, and supportive of well being, calmness, relaxation, sleep, and appetite control. For best results, take tryptophan on an empty stomach, or with a small serving of carbohydrates.