St. John's Wort (Hypericum perforatum)

Evidence-based guide to St. John's Wort: benefits, dosage, safety and interactions.

Evidence

Strong: The strongest single-herb evidence base in the book: 2008 Cochrane review of 29 RCTs (n>5,000) found Hypericum comparable to standard antidepressants for mild-moderate depression, with fewer side effects.

Traditional use and mechanism

Mild to moderate depression; perimenopausal mood disturbance; anxiety; nerve pain. European herbal medicine use for ≥2,000 years. German pharmaceutical system: registered as licensed medication for mild-moderate depression. Used in combination with black cohosh for climacteric complaints (Uebelhack 2006 RCT).

Safety

EXCELLENT efficacy in mild-moderate depression (Cochrane 2008: 29 RCTs, n>5,000; non-inferior to SSRIs with fewer dropouts). DRUG INTERACTION PROFILE IS THE PRIMARY SAFETY ISSUE — affects ~50% of all prescribed medications via CYP3A4 and P-glycoprotein induction. Photosensitivity at high doses — use sunscreen. Not appropriate if on ANY regular prescription medication without interaction check.