1 interaction related to tryptophan metabolism
Combined (estrogen-containing) oral contraceptives modestly lower the active form of vitamin B6, pyridoxal 5'-phosphate, by speeding up tryptophan metabolism. Long-term pill users tend to show lower B6 status markers than non-users. This is a depletion of a status marker rather than a clinical safety problem, and it does not affect how well the pill works.
