What is the recommended amount of St. John's wort based on clinical research?

St. John's wort is one of today's most highly recognized and clinically researched herbs. The most clinically studied form of St. John’s wort is an extract of the flowering herb that is standardized to contain 0.3% hypericin or 2.7 mg of hypericin per 900 mg of the St. John’s wort extract. Read on to learn more about the health benefits of this widely used herb and the type of extract documented by clinical research.

St. John’s wort supports a healthy mood†

Research indicates that St. John's wort plays a role in mood enhancement and maintaining a healthy, positive mental outlook. For instance, a review of 23 studies involving over 1,750 people concluded that St. John's wort was significantly superior to placebo (i.e., inactive treatment) in supporting mood enhancement. The researchers used preparations standardized to provide an amount of hypericin in the range of 0.4 mg to 2.7 mg per day from a St. John’s wort flower extract. Natrol® St. John's Wort 300 mg recommends a daily serving of 3 mg of hypericin and 900 mg of the flower extract, which is an amount found to be clinically effective.†

It is important to remember that although an extract may be standardized for one particular active constituent, it is likely to contain other active constituents as well. Interestingly, while most studies have used St. John's wort extracts based on hypericin content, some research suggests that another constituent of St. John’s wort — hyperforin — may also offer mood-related benefits.2,3†

References

  1. Linde K, Ramirez G, Mulrow CD, Pauls A, Weidenhammer W, Melchart D. St. John's wort for depression: an overview and meta-analysis of randomized clinical trials. BMJ. 1996;313:253-258. PMID: 8704532
  2. Szegedi A, Kohnen R, Dienel A, Kieser M. Acute treatment of moderate to severe depression with Hypericum extract WS® 5570 (St. John’s wort): randomized, controlled, double-blind, non-inferiority trial versus Peroxetine.BMJ. 2005;330:503. Erratum in (dosage): BMJ. 2005;330:759. PMID: 15708844
  3. Laakmann G, Schule C, Baghai T, Kieser M. St. John's wort in mild to moderate depression: the relevance of hyperforin for the clinical efficacy. Pharmacopsych 1998;31:54-59. PMID: 9684948