NA6 peptide is a bioactive protein with bioavailability of nitric oxide (nitrogen) six times higher than that achieved in the ultrafiltration of whey protein. Nitric oxide in combination with cysteine forms S-nitrosothiols, absorbed by the red blood cells and released through them. In a compound, nitric oxide dilates blood vessels, resulting in better blood circulation and oxidation of the cells. Nitric oxide also has the immune potential due to its production of white blood cells, allowing the destruction of toxic substances in the body. Also produced in nerve cells, released, spreads throughout the body, acting stimulant to the nervous system (stimulating surrounding neurons). In the sports supplementation it is used for its stimulant properties, improve oxygen metabolism and immunity. Available at www.muscle-zone.pl.