St. John's Wort

Category: adaptogen

Aliases: Hypericum perforatum, SJW, Kira

Pharmacological Mechanism

Two primary active constituents: hyperforin (non-selective monoamine reuptake inhibition via sodium-conductive pathway — distinct from classical SERT binding) + hypericin (mild MAO inhibition at high concentrations; photosensitiser). Antidepressant effect is hyperforin-mediated. Critical: hyperforin is a potent PXR activator → strongly induces CYP3A4, CYP2C9, P-glycoprotein → dramatically increases clearance of many co-administered drugs. One of the most clinically dangerous herbal supplements for drug interactions.

Half-Life (t½)

PO: 9h

Dosing Guidelines

Target Organ Systems

Interactions