Exxtra-C 1,000 mg Vitamin C is made from Quali-C, a high-grade ascorbic acid in an advanced delivery system that provides superior absorption and bioavailability. The unique microencapsulated beadlet technology allows a gradual release of Vitamin C over eight hours and a sustained release activity of 24 hours. Furthermore, new clinical studies have shown Exxtra-C to be more bioavailable than other premium Vitamin C products currently on the market. Since it is slowly broken down and released into the gastrointestinal tract, Exxtra-C is also beneficial for individuals who normally have difficulty tolerating Vitamin C in its ascorbic acid form. It is less apt to cause diarrhea or stomach upset.