Your drug-clearing machinery builds up in two weeks on St John's Wort
Fourteen days of extract raised gut CYP3A4, which clears a large share of all prescription drugs, about 1.5-fold in eight healthy men, and the drug pump P-glycoprotein about 1.4-fold.
What the study found
Two weeks of it raises the enzyme that clears most prescriptions
This is the machinery behind everything the herb does to other medicines. Fourteen days of extract raised gut CYP3A4, the enzyme that clears a large share of all prescription drugs, about 1.5-fold in eight healthy men, and the drug pump P-glycoprotein about 1.4-fold.
The caveat · No placebo, each man his own control
Eight men, no placebo arm, each compared against himself before and after. The same experiment in rats produced increases of two to nearly four-fold, so the animal figures are not the human ones and must never stand in for them. Gut expression came from biopsy; the liver claim rests on a breath test.