St. John's Wort

Last Updated: June 20, 2024

St. John’s wort, also known by its Linnean name of Hypericum perforatum (HP), is an anti-depressant herb that is commonly used for its neurological effects. While it appears effective, it is well known to adversely interact with a variety of pharmaceuticals.

dosageDosage
examine-databaseExamine Database
research-feedResearch feed

St. John's Wort is most often used for

What is St. John’s wort?

St. John's wort, or Hypericum perforatum, is a yellow-flowered plant native to Europe that is traditionally associated with St. John's feast day and believed to protect against malevolent spirits. It contains active compounds like hypericin and hyperforin and is commonly used in traditional medicine to treat depression.

What are the main benefits of St. John’s wort?

St. John's wort is effective for treating mild to moderate depression and has show similar clinical responses as selective serotonin reuptake inhibitors (SSRIs), with fewer side effects and lower dropout rates than tricyclic antidepressants. Additionally, it may enhance neuronal plasticity and neurogenesis while exhibiting anti-inflammatory properties and protecting neurons from cytotoxicity.

What are the main drawbacks of St. John’s wort?

The main drawbacks of St. John's wort include its potential to interfere with the metabolism of various medications, which leads to reduced effectiveness or unexpected outcomes, particularly with oral contraceptives, anticoagulants, and certain antidepressants, which may increase the risk of serotonin syndrome. Additionally, commonly reported side effects include gastrointestinal issues, headache, fatigue, and photosensitivity, and further research is needed to assess its safety profile.

Does St. John’s wort interact with any other medication?

Can St. John’s wort interact with other supplements?

Is St. John’s wort safe during pregnancy?

Is St. John’s wort safe during breastfeeding?

How does St. John’s wort work?

St. John's wort, particularly its active compound hyperforin, may enhance mood by inhibiting the reuptake of neurotransmitters like serotonin, norepinephrine, and dopamine through mechanisms that differ from those of traditional selective serotonin reuptake inhibitors (SSRIs). Additionally, hyperforin activates the pregnane-X-receptor, which influences the cytochrome P450 system and potentially affects drug interactions.

Does St. John’s wort have other mechanisms of action?

What are other names for St. John's Wort?
Note that St. John's Wort is also known as:
  • St. John's Wort
  • Hypericum Perforatum
  • Klamath Weed
  • Tipton Weed
  • Johanniskraut
  • 圣约翰草 (Guan Ye Lian Qiao)
Dosage information

The most common dosage of St. John's wort extract found in studies is 300mg, taken up to three times a day (for a total of 900 mg).[1]

Supplements Demystified: Get Our Unbiased, Evidence-Based Guide

Examine Database: St. John's Wort
What works and what doesn't?

Unlock the full potential of Examine

Get started

Don't miss out on the latest research

Update History
2024-06-20 00:30:03

Dosage info clarification

minor

Some of the wording in our dosage section was unclear. St. John's Wort studies generally administer 300 mg of extract up to 3 times daily (300 to 900 mg overall).

Written By

Nick Milazzo
2023-10-07 00:30:04

New meta-analyses added

minor

We added a few meta-analyses to our database and update the clinical effects accordingly.

Written By

Giulia Guerrini

Reviewed By

Nick Milazzo
References
  1. ^Ng QX, Venkatanarayanan N, Ho CYClinical use of Hypericum perforatum (St John's wort) in depression: A meta-analysis.J Affect Disord.(2017-Mar-01)
  2. ^Peterson B, Nguyen HSt John's WortStatPearls.(2023-05)
  3. ^Zhao X, Zhang H, Wu Y, Yu CThe efficacy and safety of St. John's wort extract in depression therapy compared to SSRIs in adults: A meta-analysis of randomized clinical trials.Adv Clin Exp Med.(2022-Oct-11)
  4. ^Knüppel L, Linde KAdverse effects of St. John's Wort: a systematic review.J Clin Psychiatry.(2004-Nov)
  5. ^Bonaterra GA, Schwendler A, Hüther J, Schwarzbach H, Schwarz A, Kolb C, Abdel-Aziz H, Kinscherf RNeurotrophic, Cytoprotective, and Anti-inflammatory Effects of St. John's Wort Extract on Differentiated Mouse Hippocampal HT-22 Neurons.Front Pharmacol.(2017)
  6. ^McDonnell AM, Dang CHBasic review of the cytochrome p450 system.J Adv Pract Oncol.(2013-Jul)
  7. ^Bauer S, Störmer E, Johne A, Krüger H, Budde K, Neumayer HH, Roots I, Mai IAlterations in cyclosporin A pharmacokinetics and metabolism during treatment with St John's wort in renal transplant patients.Br J Clin Pharmacol.(2003 Feb)
  8. ^Hennessy M, Kelleher D, Spiers JP, Barry M, Kavanagh P, Back D, Mulcahy F, Feely JSt Johns wort increases expression of P-glycoprotein: implications for drug interactions.Br J Clin Pharmacol.(2002-Jan)
  9. ^Whiskey E, Werneke U, Taylor DA systematic review and meta-analysis of Hypericum perforatum in depression: a comprehensive clinical review.Int Clin Psychopharmacol.(2001-Sep)
  10. ^Singer A, Wonnemann M, Müller WEHyperforin, a major antidepressant constituent of St. John's Wort, inhibits serotonin uptake by elevating free intracellular Na+1.J Pharmacol Exp Ther.(1999-Sep)
  11. ^Thiede HM, Walper AInhibition of MAO and COMT by hypericum extracts and hypericin.J Geriatr Psychiatry Neurol.(1994-Oct)
  12. ^Butterweck VMechanism of action of St John's wort in depression : what is known?CNS Drugs.(2003)
  13. ^Mathijssen RH, Verweij J, de Bruijn P, Loos WJ, Sparreboom AEffects of St. John's wort on irinotecan metabolism.J Natl Cancer Inst.(2002 Aug 21)
  14. ^Zhou S, Chan E, Pan SQ, Huang M, Lee EJPharmacokinetic interactions of drugs with St John's wort.J Psychopharmacol.(2004 Jun)
  15. ^Russo E, Scicchitano F, Whalley BJ, Mazzitello C, Ciriaco M, Esposito S, Patanè M, Upton R, Pugliese M, Chimirri S, Mammì M, Palleria C, De Sarro GHypericum perforatum: pharmacokinetic, mechanism of action, tolerability, and clinical drug-drug interactions.Phytother Res.(2014 May)
  16. ^Wang XD, Li JL, Lu Y, Chen X, Huang M, Chowbay B, Zhou SFRapid and simultaneous determination of nifedipine and dehydronifedipine in human plasma by liquid chromatography-tandem mass spectrometry: Application to a clinical herb-drug interaction study.J Chromatogr B Analyt Technol Biomed Life Sci.(2007 Jun 1)
  17. ^Tannergren C, Engman H, Knutson L, Hedeland M, Bondesson U, Lennernäs HSt John's wort decreases the bioavailability of R- and S-verapamil through induction of the first-pass metabolism.Clin Pharmacol Ther.(2004 Apr)
  18. ^Chen XW, Serag ES, Sneed KB, Liang J, Chew H, Pan SY, Zhou SFClinical herbal interactions with conventional drugs: from molecules to maladies.Curr Med Chem.(2011)
  19. ^Morimoto T, Kotegawa T, Tsutsumi K, Ohtani Y, Imai H, Nakano SEffect of St. John's wort on the pharmacokinetics of theophylline in healthy volunteers.J Clin Pharmacol.(2004 Jan)
  20. ^Lau WC, Welch TD, Shields T, Rubenfire M, Tantry US, Gurbel PAThe effect of St John's Wort on the pharmacodynamic response of clopidogrel in hyporesponsive volunteers and patients: increased platelet inhibition by enhancement of CYP3A4 metabolic activity.J Cardiovasc Pharmacol.(2011-Jan)
  21. ^Roby CA, Anderson GD, Kantor E, Dryer DA, Burstein AHSt John's Wort: effect on CYP3A4 activity.Clin Pharmacol Ther.(2000-May)
  22. ^Hammerness et al.St. John’s Wort: A Systematic Review of Adverse Effects and Drug Interactions for the Consultation PsychiatristPsychosomatics.(2003-07-01)
  23. ^Spiess D, Winker M, Dolder Behna A, Gründemann C, Simões-Wüst APAdvanced Safety Assessment of Herbal Medicines for the Treatment of Non-Psychotic Mental Disorders in Pregnancy.Front Pharmacol.(2022)
  24. ^Moretti ME, Maxson A, Hanna F, Koren GEvaluating the safety of St. John's Wort in human pregnancy.Reprod Toxicol.(2009-Jul)
  25. ^St. John's Wort.Drugs and Lactation Database (LactMed®).(2006)
Examine Database References
  1. Depression Symptoms - Linde K, Berner MM, Kriston LSt John's wort for major depression.Cochrane Database Syst Rev.(2008-Oct-08)
  2. Depression Symptoms - Rahimi R, Nikfar S, Abdollahi MEfficacy and tolerability of Hypericum perforatum in major depressive disorder in comparison with selective serotonin reuptake inhibitors: a meta-analysis.Prog Neuropsychopharmacol Biol Psychiatry.(2009-Feb-01)
  3. Depression Symptoms - Linde K, Berner M, Egger M, Mulrow CSt John's wort for depression: meta-analysis of randomised controlled trials.Br J Psychiatry.(2005-Feb)
  4. Depression Symptoms - Cui YH, Zheng YA meta-analysis on the efficacy and safety of St John's wort extract in depression therapy in comparison with selective serotonin reuptake inhibitors in adults.Neuropsychiatr Dis Treat.(2016)
  5. Depression Symptoms - Whiskey E, Werneke U, Taylor DA systematic review and meta-analysis of Hypericum perforatum in depression: a comprehensive clinical review.Int Clin Psychopharmacol.(2001-Sep)
  6. Depression Symptoms - Ng QX, Venkatanarayanan N, Ho CYClinical use of Hypericum perforatum (St John's wort) in depression: A meta-analysis.J Affect Disord.(2017-Mar-01)
  7. Depression Symptoms - Zhao X, Zhang H, Wu Y, Yu CThe efficacy and safety of St. John's wort extract in depression therapy compared to SSRIs in adults: A meta-analysis of randomized clinical trials.Adv Clin Exp Med.(2022-Oct-11)