Source Naturals - L-Tryptophan - 500 mg - 90 Capsules Source Naturals L-Tryptophan helps support relaxation, restful sleep, and positive mood. It plays a part in the synthesis of both melatonin and serotonin, hormones involved with mood and stress response and sleep/wake cycles. 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 system, the metabolism of food, and the production of hydrochloric acid for the digestive system. Source Naturals L-Tryptophan is extremely pure and is regularly tested to ensure the highest standards of quality. L-Tryptophan addresses the following body systems: Sugar Regulation Metabolism/Hormones Cognition/Nerves Immune Leaders of the Wellness Revolution Source Naturals was created in 1982 by C.E.O Ira Goldberg to support each individual's potential to enjoy optimal health. At that time, the kind of nutritional formulations he envisioned - for the maintenance of well-being and the enhancement of life - simply didn't exist. The idea of combining many nutrients, herbs and nutraceuticals in one formulation, though common today, was then a rarity. Source Naturals pioneered the concept with Wellness Formula, now the industry's #1 immune support product. Source Naturals subsequently introduced numerous award-winning formulas, recognized for their excellence in independent surveys and nutritional analyses. In addition to Wellness, these award-winners include Life Force Multiple, Mega-Kid Multiple, Inflama-Rest, the Skin Eternal line, Higher Mind, Essential Enzymes, Male Response, and more. Source Naturals' comprehensive Bio-Aligned Formulas help bring the power of alignment to your body. When formulating, they evaluate the underlying causes of system imbalances, and then provide targeted nutrition to interdependent body systems.