This study examined blood vitamin C concentrations for 25 hours following administration of 1000mg of vitamin C taken all at once, 100mg of vitamin C consumed hourly for 10 hours, and 500mg of vitamin C in the form of a sustained release preparation taken twice at a 5-hour interval. Results showed that the sustained release preparation produced blood vitamin C levels comparable to consuming 100mg of vitamin C on an hourly basis. The largesse immediate-release preparation produced significantly lower blood vitamin C levels over the 25-hour period due to a faster rate of urinary vitamin C excretion.*
*. Chuck C, Print S, Pattision T, Whittam J, Scala J. Urine and plasma ascorbic acid levels in humans after administration of immediate and sustained-release ascorbic acid tablets. Data on file, Shaklee Corporation.