Nutralife Ester-C High Strength + BioflavonoidsNutra Life Ester C 1500mg + Bioflavonoids, contains a stomach friendly, long lasting Vitamin C, that works to provide 24 hour support to your immune system. By staying in the white blood cells longer than standard vitamin C, your immune system stays protected for a whole 24 hours, removing the need for dosing throughout the day. Bioflavonoids work to support strong and healthy respiratory, connective and cardiovascular tissues.