Condition
    Strong Evidence
    Effectiveness 4/5

    St. Johns Wort for Depression

    St John's wort is as effective as standard antidepressants for mild to moderate depression across 29 Cochrane-reviewed trials, with fewer dropouts for side effects — but its drug interactions are severe enough to disqualify most people taking any medication.

    Overview

    St John's wort has better trial evidence than almost any other herbal antidepressant. Cochrane and later meta-analyses consistently find standardised extracts superior to placebo in mild to moderate depression and broadly comparable to SSRIs, with fewer people stopping because of side effects. On efficacy alone it is a credible option. The problem is not efficacy but interactions. St John's wort is a potent inducer of CYP3A4, CYP2C9 and P-glycoprotein, and it can halve blood levels of many prescription drugs. Contraceptive failure, transplant rejection and loss of HIV viral suppression are documented outcomes, not theoretical ones. That is why this belongs in a conversation with a prescriber rather than a supermarket basket.

    Verdict

    Likely effective

    Cochrane and multiple meta-analyses find standardised St John's wort extract superior to placebo in mild to moderate depression and similar in effect to SSRIs, with better tolerability. Evidence in severe depression is weaker and one large US trial was negative.

    How It Works

    The active chemistry is plural rather than singular. Hyperforin, hypericin and various flavonoids contribute, and hyperforin appears to do most of the antidepressant work by inhibiting reuptake of serotonin, noradrenaline, dopamine, GABA and glutamate through a non-selective mechanism involving raised intracellular sodium. Chronic dosing also downregulates beta-adrenergic and upregulates serotonergic post-synaptic receptors, a pattern shared with conventional antidepressants. Hyperforin is also the source of the interaction problem. It activates the pregnane X receptor, which drives expression of CYP3A4 and P-glycoprotein. Induction builds over one to two weeks and takes a similar time to wear off after stopping — which means interactions persist beyond the last dose.

    Pathways involved

    Non-selective monoamine reuptake inhibition
    Hyperforin activity
    Pregnane X receptor activation
    CYP3A4 and CYP2C9 induction
    P-glycoprotein induction
    Post-synaptic receptor adaptation

    Dosing & Protocol

    Trials almost universally used standardised extracts at 300 mg three times daily, standardised to around 0.3 percent hypericin or 3 to 5 percent hyperforin. Extracts studied by name include WS 5570, LI 160 and ZE 117; the last is deliberately low in hyperforin and therefore causes less enzyme induction, which matters if interactions are the main worry. Unstandardised teas and tinctures were not what the trials tested and cannot be assumed equivalent. Expect four to six weeks at full dose before judging the effect, and taper over one to two weeks when stopping rather than stopping abruptly, since discontinuation symptoms have been reported.
    ScenarioDoseFormTiming
    Mild to moderate depression300 mg three times dailyStandardised extract, 0.3% hypericinWith meals
    Once-daily alternative600-900 mg dailyStandardised extractMorning, with food
    Interaction-sensitive users500-1000 mg dailyLow-hyperforin extract (e.g. ZE 117)With food, after prescriber review
    StoppingReduce over 1-2 weeksAnyDo not stop abruptly
    1. 1

      Review every medication first· Before starting

      List prescriptions, contraception and other supplements with a pharmacist or doctor. This step is not optional with St John's wort.

    2. 2

      Use a standardised extract· Weeks 1-6

      300 mg three times daily of an extract standardised to hypericin content, matching what trials used.

    3. 3

      Add non-hormonal contraception if relevant· Entire course

      Enzyme induction reduces contraceptive efficacy; barrier methods are needed throughout and for two weeks after stopping.

    4. 4

      Use sun protection· Ongoing

      Photosensitivity increases, especially at higher doses and in fair skin. Sunscreen and cover-up matter.

    5. 5

      Review at 6 weeks· Week 6

      If mood has not improved meaningfully, stop and seek assessment rather than continuing indefinitely.

    Evidence

    The Cochrane review of St John's wort for major depression pooled 29 trials with over 5,000 patients and concluded that extracts were superior to placebo, similarly effective to standard antidepressants and better tolerated, while noting that trials from German-speaking countries reported larger effects than those elsewhere. A meta-analysis comparing extract with SSRIs reached the same conclusion on efficacy and found fewer adverse-event withdrawals, and a later systematic review of major depressive disorder and a 2017 meta-analysis in the Journal of Affective Disorders confirmed the pattern. The important counterweight is the JAMA randomised controlled trial in major depressive disorder, which found no benefit over placebo — though that trial also failed to separate its active comparator from placebo, which complicates interpretation. Taken together, the evidence supports use in mild to moderate depression and does not support it as a substitute for treatment in severe depression.
    Best available evidence
    Cochrane review plus several meta-analyses and randomised trials
    Typical effect
    Response rates comparable to SSRIs in mild to moderate depression; fewer side-effect withdrawals
    Studied dose
    300 mg standardised extract three times daily
    Time to effect
    4-6 weeks
    Certainty of evidence
    Strong in mild to moderate depression; weak in severe depression

    The Cochrane review of St John's wort for major depression, meta-analyses comparing extract with SSRIs, a systematic review in major depressive disorder, and the negative JAMA randomised controlled trial.

    Effect of Hypericum perforatum (St John's wort) in major depressive disorder: a randomized controlled trial

    Score: 9/10
    2002
    rct
    n=340

    Hypericum Depression Trial Study Group

    St John's wort was not effective for moderately severe major depression in this trial.

    View source

    A 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

    Score: 7/10
    2016
    meta_analysis

    Zheng Y, Cui Y

    Hypericum extract is an effective and better-tolerated alternative to SSRIs in adult depression.

    View source

    A systematic review of St. John's wort for major depressive disorder

    Score: 8/10
    2016
    systematic_review

    Apaydin EA, Maher AR, Shanman R +4 more

    Evidence supports use in mild to moderate MDD only; safety concerns centre on drug interactions.

    View source

    Clinical use of Hypericum perforatum (St John's wort) in depression: a meta-analysis

    Score: 8/10
    2017
    meta_analysis

    Ng QX, Venkatanarayanan N, Ho CY

    St John's wort is comparable to SSRIs for mild to moderate depression with better tolerability.

    View source

    St John's wort for major depression

    Score: 9/10
    2008
    systematic_review
    n=5489

    Linde K, Berner MM, Kriston L

    St John's wort is effective for mild to moderate major depression with better tolerability than standard antidepressants.

    View source

    Safety

    Direct side effects are generally mild — gastrointestinal upset, dry mouth, restlessness, headache and photosensitivity, which is dose-related and more troublesome in fair skin. Trial withdrawal rates were lower than with SSRIs, which is part of the appeal. The hazards lie elsewhere. Combining St John's wort with SSRIs, SNRIs, triptans or tramadol risks serotonin syndrome. In undiagnosed bipolar disorder it can precipitate mania, as any antidepressant can. And because enzyme induction reduces the effectiveness of many essential medicines, the danger is often to the treatment of another condition rather than from the herb itself. It should be avoided in pregnancy and breastfeeding, where safety data are inadequate.

    Get help, not just a supplement

    Depression with hopelessness, inability to function, or any thought of self-harm needs urgent professional assessment. St John's wort is not a substitute for care in moderate to severe depression, and it should never be combined with a prescribed antidepressant without medical supervision.

    Interactions & Conflicts

    Interacts withSeverityMechanismAction
    Hormonal contraceptives
    high
    		CYP3A4 induction lowers hormone levels; breakthrough bleeding and pregnancy reportedUse additional non-hormonal contraception during use and for 2 weeks after
    SSRIs, SNRIs, triptans, tramadol
    high
    		Additive serotonergic activity risking serotonin syndromeDo not combine without specialist supervision
    Warfarin
    high
    		CYP2C9 induction reduces anticoagulant effect and INRAvoid; if unavoidable, INR must be monitored closely
    Ciclosporin, tacrolimus and other immunosuppressants
    high
    		Marked reduction in drug levels; transplant rejection documentedContraindicated
    HIV protease inhibitors and NNRTIs
    high
    		Reduced antiretroviral levels and loss of viral suppressionContraindicated
    Digoxin, statins, anticonvulsants and some chemotherapy agents
    high
    		CYP3A4 and P-glycoprotein induction lowers plasma levelsAvoid; review with prescriber before any use

    References

    1. Linde K et al. St John's wort for major depression. Cochrane Database Syst Rev. 2008
    2. Ng QX et al. Clinical use of Hypericum perforatum in depression: a meta-analysis. J Affect Disord. 2017
    3. Hypericum Depression Trial Study Group. Effect of Hypericum perforatum in major depressive disorder: a randomized controlled trial. JAMA. 2002

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