Dietary supplement. Rich supply of B-Complex Vitamins. Better digestion, absorption, assimilation, and utilization. B Complex formula. Packaged in high quality, shatterproof bottle. The L-Tryptophan in this product is naturally present in the protein. It is not added or manufactured. The yeast in this product is 100% natural, therefore, the color of the product may vary. TwinLab's Liquid Yeast contains a rich supply of B-Complex vitamins and natural enzymatic digested yeast in liquid form for better digestion, absorption, assimilation and utilization. Liquid Yeast is a highly concentrated protein source produced form the action of natural enzymes on pure living yeast cells. It contains all the essential amino acids as well as mineral and B-complex Vitamins. Since the yeast is enzymatically digested, the nutrients are more readily available to the body than nutrients from other yeasts.