Reviews of the research place the effectiveness of the herb at about 55 percent. St. John's wort is relatively side effect-free. There are no known contraindications, and use during pregnancy and lactation is not restricted. The recommended dose is 300 mg of a standardized extract taken three times a day. Extracts are typically standardized to 0.3 percent hypericin, but because new research indicates hyperforin is actually the active constituent, some formulations are now standardized to between 3 and 5 percent hyperforin.
Effects can take up to four weeks to be apparent.
Depression is a serious condition and should be addressed with the help of a health care provider. Do not switch from a prescription antidepressant to St. John's wort or combine the herb with other pharmaceuticals without consultation. Growing St. John's Wort St. John's wort is a perennial herb native to Europe, North Africa and western Asia. Now it is found throughout the Americas as well as Africa, Asia and Australia. It grows wild in uncultivated ground, woods, roadsides and meadows and is typically one to three feet tall.