St. John’s Wort Extract

St. John’s Wort (Hypericum perforatum) is an aromatic perennial that is native to Europe and Western Asia. St. John’s Wort extract is prepared from the aerial parts of the plant, which are gathered during the flowering season. A liquid extract of the herb is prepared by percolation of the ground clean herb, which is concentrated and spray-dried into powder form. St. John’s Wort contains catechins-type tannins, proanthocyanidins, flavonoids, and phenolic acids.1 The powdered herbal extract must meet a guaranteed level of total hypericin, a group of phytochemical compounds that occur naturally in St. John’s Wort.

Health Benefits

St. John’s Wort has traditionally been used to help improve mood and may be helpful in the treatment of mild to moderate depression.1-4 Supplementation of St. John’s Wort may decrease physical and behavioral symptoms of PMS (premenstrual syndrome) and severity, frequency, and duration of hot flashes in postmenopausal women.5,6


Due to drug interactions between St. John’s Wort and some medications, US government agency is in the process of including “drug-herb” interaction warnings on products containing St. John’s Wort.2


  1. St. John’s Wort. American Botanical Council. Accessed in August 2015.
  2. St. John’s Wort. MedlinePlus. NIH. Accessed in August 2015.
  3. Brattström A. Long-term effects of St. John’s wort (Hypericum perforatum) treatment: a 1-year safety study in mild to moderate depression. Phytomedicine. 2009 Apr;16(4):277-83. doi: 10.1016/j.phymed.2008.12.023. Epub 2009 Mar 18. PubMed PMID: 19299116.
  4. Mannel M, Kuhn U, Schmidt U, Ploch M, Murck H. St. John’s wort extract LI160 for the treatment of depression with atypical features – a double-blind, randomized, and placebo-controlled trial. J Psychiatr Res. 2010 Sep;44(12):760-7. doi: 10.1016/j.jpsychires.2010.01.010. Epub 2010 Feb 23. PubMed PMID: 20181361.
  5. Canning S, Waterman M, Orsi N, Ayres J, Simpson N, Dye L. The efficacy of Hypericum perforatum (St John’s wort) for the treatment of premenstrual syndrome: a randomized, double-blind, placebo-controlled trial. CNS Drugs. 2010 Mar;24(3):207-25. doi: 10.2165/11530120-000000000-00000. PubMed PMID: 20155996.
  6. Abdali K, Khajehei M, Tabatabaee HR. Effect of St John’s wort on severity, frequency, and duration of hot flashes in premenopausal, perimenopausal and postmenopausal women: a randomized, double-blind, placebo-controlled study. Menopause. 2010 Mar;17(2):326-31. doi: 10.1097/gme.0b013e3181b8e02d. PubMed PMID: 20216274.