St. John's Wort

St. John's wort is found in Europe and the United States; it is especially abundant in northern California and southern Oregon. The above-ground (aerial) parts of the plant are gathered during the flowering season. Similar species are found around the world.

In ancient Greece, the herb was used to treat many ailments, including sciatica and poisonous reptile bites. In Europe, St. John’s wort was, and continues to be, very popular for the topical treatment of wounds and burns. It is also a folk remedy for kidney and lung ailments as well as depression.

Active constituents of St. John's Wort

St. John’s wort has a complex diverse chemical makeup that includes hypericin and other dianthrones, flavonoids, xanthones, and hyperforin. While it was previously thought that the antidepressant actions of St. John’s wort were due to hypercin and inhibition of the enzyme monoamine oxidase, current research has challenged this belief. Recent studies have focused on other constituents, such as hyperforin, xanthones, and flavonoids.

New research suggests that St. John’s wort extracts exert their antidepressant actions by inhibiting the reuptake of the neurotransmitters serotonin, norepinephrine, and dopamine. This action is possibly due to the constituent hyperforin. By making more of these neurotransmitters available to the brain, St. John’s wort is able to act as an antidepressant.

How much St. John's Wort is usually taken?

The standard recommendation for mild to moderate depression is 300 mg of St. John’s wort extract three times daily. Higher intakes may be used, under the supervision of a healthcare professional, for more severe depression. Results can be noted as early as two weeks, and length of use should be discussed with a healthcare professional. Although research has used only standardized extracts, the German Commission E monograph suggests a daily amount of 2–4 grams of the whole herb.