“In vitro studies revealed a markedly higher rate of oxidation of ascorbic acid in the presence of either estinyl or progestogen than in untreated controls.”
“Oral … either estinyl (5 micrograms) or progestogen (250 … combination with 5 mg of ascorbic acid (minimum requirement) daily for 21 d, resulted in significantly lower (P less than 0.05) concentrations of … acid in plasma, liver, adrenals and urine than in animals receiving only 5 mg of the vitamin.”