RATE OF EXCRETION OF VITAMIN-C IN HUMAN URINE

The dosage of vitamin C necessary to maintain a level in the urine whi ch could be detected using the 2,6-dichlorophenolindophenol assay was determined with undergraduate students. Students taking 250 mg daily d id not excrete significant levels of vitamin C in their urine, while e xcretion increased al doses from 0.5 to 2 g. A 2 g daily dose caused d etectable excretion from about 4 until 16 hr later, on both the first and eighth day. A dose of 500 mg taken every 12 hr led to continuously -detectable levels of vitamin C in the urine. The conclusion is that t wo conditions are necessary to elevate vitamin c excretion continuousl y: a dose of at least 500 mg and a dose every 12 hr. This is substanti ally higher than the U.S. recommended daily allowance and more frequen t than administration being used in clinical trials.