Possible Interaction: Progestins and Tryptophan

“Studies carried out in different countries during the last 15 years have provided evidence that supplementation with (or excess of) estro-progestational hormones may be accompanied by an increased urinary excretion of tryptophan metabolites, as happens in pyridoxine deficiency.”

“Administration of both estrogen and gestogen caused increased urinary excretion of meta bolites of tryptophan and nicotinic acid after a loading dose of tryptophan , whereas gestogens alone caused decreased urinary excretion of nicotinic acid metabolites.”