Pepsin - the proteolytic enzyme of gastric juice, which is produced of the pepsinogen, secreted gastric mucosa. This reaction occurs only in an acidic environment. Pepsin is responsible for the initial stage of digestion of proteins, and thus breaking them into smaller molecules - polypeptides and oligopeptides, which are degraded into separate amino acids during the further digestive process. Insufficient amount of enzyme leads to disruption of protein digestion process. Supplementation with pepsin not only leads to a proper amount of this component, but also is directly stimulating the endogenous conversion of pepsinogen to pepsin and therefore operates two separate pathways.