St. John's Wort

Metadata

Approved Indications

Commission E (Germany, 1984/revised)

• Approved: Internally for psychovegetative disturbances, depressive moods, anxiety, and/or nervous unrest
• Approved: Oily preparations externally and internally for treatment and post-therapy of acute and contused injuries, myalgia, and first-degree burns

ESCOP (European Scientific Cooperative on Phytotherapy, 2018 revision)

• Approved: Mild depressive episodes (for extracts with higher hyperforin content)
• Approved: Mild to moderate depressive episodes (for well-characterized standardized extracts)
• Approved: Relief of temporary mental exhaustion
• Approved: Symptomatic treatment of minor inflammations of the skin (such as sunburn)
• Approved: Aid in healing of minor wounds

EMA/HMPC (European Medicines Agency, 2023 revision)

• Well-established use: Treatment of mild to moderate depressive episodes (specific dry extracts)
• Traditional use: Symptomatic relief of mild gastrointestinal discomfort (expressed juice)
• Traditional use: Supportive treatment of nervous restlessness and associated difficulties in falling asleep (comminuted herbal drug)
• Traditional use: Symptomatic relief of minor inflammations of the skin and as an aid in healing of minor wounds (oily liquid preparations)

Agreement/Disagreement Across Monographs

All three European bodies agree on the core indication for depression. The EMA’s distinction between “well-established use” (specific standardized dry extracts for depression) and “traditional use” (other preparations for other indications) provides the most nuanced framework. Commission E’s scope is broader and includes psychovegetative disturbances and anxiety, which ESCOP and EMA are more cautious about endorsing as standalone indications.

Conditions Treated

Primary (Strong Evidence)

• Mild to moderate major depressive episodes — The headline indication with massive clinical support
• Sometimes classified by severity: mild depressive episodes (broader range of preparations) vs. moderate episodes (specific standardized extracts only)

Secondary (Moderate Evidence)

• Somatoform disorders / somatic anxiety
• Menopausal mood symptoms / quality of life during menopause
• Premenstrual syndrome (PMS) — mild symptoms

Traditional/Historical (Limited Evidence)

• Nervous restlessness and sleep difficulties
• Minor skin inflammation, wound healing, sunburn (topical oily preparations)
• Mild gastrointestinal discomfort

Mechanism of Action

St. John’s Wort has a complex, multimodal mechanism that affects multiple neurotransmitter systems:

Primary Mechanisms

1. Monoamine reuptake inhibition: Hyperforin inhibits the synaptic reuptake of serotonin (5-HT), norepinephrine (NE), dopamine (DA), GABA, and glutamate. This is unique — no single conventional antidepressant inhibits reuptake of all five of these neurotransmitters.
2. Mechanism of reuptake inhibition: Hyperforin activates TRPC6 (transient receptor potential channel 6), which raises intracellular sodium levels and subsequently reduces the sodium gradient needed for neurotransmitter reuptake transporters to function.
3. Neuroendocrine effects: Downregulation of beta-adrenergic receptors and upregulation of serotonin (5-HT1A and 5-HT2A) receptors, similar to conventional antidepressants.

Secondary Mechanisms

4. GABA and glutamate receptor modulation: Activation of GABA-A and glutamate receptor systems
5. Anti-inflammatory effects: Inhibition of interleukin-6, relevant to neuroinflammatory models of depression
6. Photodynamic activity: Hypericin has photodynamic and antiviral properties (relevant to topical use)

Key Insight: Hyperforin vs. Hypericin

• Hyperforin is now considered the primary antidepressant constituent and is also the primary driver of CYP enzyme induction (via PXR activation)
• Hypericin was historically assumed to be the active constituent (hence standardization to hypericin content), but clinical evidence points to hyperforin as more important for antidepressant activity
• Low-hyperforin extracts (e.g., Ze 117, with <1 mg hyperforin per dose) may have a more favorable drug interaction profile while retaining some antidepressant efficacy [Source: PMC6766782]

Clinical Evidence Summary

Volume of Evidence

This is one of the most extensively researched herbal medicines globally:

• 35+ randomized controlled trials examining approximately 6,993+ patients
• Multiple systematic reviews and meta-analyses
• Cochrane systematic review (last updated 2008)

Key Meta-Analyses

Cochrane Review (Linde et al., 2008)

• Included 29 RCTs (n = 5,489)
• vs. Placebo: St. John’s Wort extracts were significantly superior (RR for response 1.48, 95% CI 1.23-1.77)
• vs. Standard antidepressants: No significant difference in efficacy
• Side effects: Significantly fewer side effects than standard antidepressants; dropout rates due to adverse events significantly lower
• Caveat: Noted that larger, more rigorous trials from Germany showed stronger effects than trials from other countries, raising questions about methodological or contextual differences

Rahimi et al. (2009) — SJW vs. SSRIs Meta-Analysis

• Focused specifically on comparison with SSRIs in major depressive disorder
• Conclusion: No difference in efficacy between Hypericum and SSRIs
• Key advantage: Significantly lower withdrawal rates for Hypericum due to adverse events

Apaydin et al. (2016) — Systematic Review

• 35 studies, 6,993 patients
• St. John’s Wort was associated with significantly more treatment responders than placebo: RR 1.53 (95% CI 1.19-1.97)
• Standardized mean difference vs. placebo: 0.49 (moderate effect size)
• Quality of evidence rated as moderate

Notable Individual Trials

• Hypericum Depression Trial Study Group (Shelton et al., 2001, JAMA): Large US trial found SJW not superior to placebo in moderately severe MDD — but the placebo response rate was unusually high, and the SSRI comparator (sertraline) also failed to separate from placebo
• Lecrubier et al. (2002): WS 5570 300 mg TID equivalent to paroxetine 20 mg/day for moderate depression
• Szegedi et al. (2005): WS 5570 equivalent to paroxetine in moderate-severe depression, with significantly better tolerability

Onset of Action

Clinical effects typically emerge after 2-4 weeks of consistent use, similar to conventional antidepressants.

European vs. US/Anglophone Consensus

The German vs. US Trial Quality Debate

The Cochrane review noted that German trials tended to show larger effect sizes than non-German trials. Possible explanations include: (1) German trials used well-characterized standardized extracts while some non-German trials used variable products, (2) German trials typically enrolled patients with milder depression where SJW works best, (3) cultural differences in placebo response rates and diagnostic thresholds.

Safety Profile

Contraindications

• Absolute: Concurrent use with immunosuppressants (cyclosporine, tacrolimus), antiretrovirals (indinavir, other protease inhibitors), and other drugs with narrow therapeutic indices metabolized by CYP3A4
• Absolute: Known hypersensitivity to Hypericum preparations
• Relative: Moderate-severe depression requiring conventional antidepressants (risk of serotonin syndrome if combined)
• Relative: Concurrent use with oral contraceptives (reduced efficacy leading to breakthrough bleeding or unplanned pregnancy)

Drug Interactions — THE CRITICAL SAFETY ISSUE

St. John’s Wort has the most extensive drug interaction profile of any herbal medicine. The primary mechanism is potent induction of CYP3A4 (and to lesser degrees CYP2C9, CYP1A2, CYP2C19) and P-glycoprotein, mediated by hyperforin acting as a potent ligand for the pregnane X receptor (PXR).

Pharmacokinetic Interactions (CYP/P-gp Induction — Reduced Drug Levels)

Pharmacodynamic Interactions (Serotonin Syndrome Risk)

Note on low-hyperforin extracts: Ze 117 (Remotiv), with hyperforin content <1 mg per dose, has shown no clinically relevant CYP3A4 induction in pharmacokinetic studies. This suggests the drug interaction problem is primarily a hyperforin problem, and low-hyperforin extracts may offer a safer alternative. However, this remains an active area of investigation. [Source: PMC6766782]

Side Effects

• Common: Gastrointestinal symptoms (nausea, diarrhea), dizziness, confusion, fatigue, dry mouth
• Photosensitivity: Dose-related; more common at doses >1800 mg/day but can occur at standard doses. Patients should be advised to use sun protection.
• Rare: Allergic skin reactions, restlessness, hypomania (especially in patients with bipolar predisposition)

Pregnancy and Lactation

• Pregnancy: Limited human data. Three observational studies did not find increased risk of birth defects. Animal studies suggest no cognitive or behavioral teratogenicity but possible reduced birth weight. EMA/HMPC: Not recommended during pregnancy due to insufficient data. [CONTESTED — some practitioners consider it relatively safe based on available data]
• Lactation: Small amounts of hypericin and hyperforin are detected in breast milk. Limited studies suggest minimal risk to nursing infants. Occasional reports of colic, drowsiness, or lethargy in breastfed infants. EMA/HMPC: Not recommended during lactation. [Source: LactMed/NCBI]

Clinical Dosage

Standard Dosage for Depression

• Dried extract (standardized): 300 mg three times daily (total 900 mg/day)
• Standardization: 0.3% hypericin or 2-5% hyperforin
• Duration: Minimum 4-6 weeks for initial assessment; continuation therapy for 6-12 months as with conventional antidepressants

Dosage by Extract

Commission E / ESCOP Recommended Dose

• 2-4 g of crude drug or equivalent preparations corresponding to 0.2-1.0 mg total hypericin daily
• In practice: 900 mg/day standardized extract for depression

Dose Range in Clinical Trials

• 300-1800 mg/day; most positive trials used 900 mg/day

Sources

• EMA/HMPC European Union Herbal Monograph on Hypericum perforatum L., herba (2023 revision)
• ESCOP Monograph: Hyperici herba (2018)
• Expanded Commission E Monograph: St. John’s Wort
• Cochrane Review: Linde K et al. St John’s wort for major depression. Cochrane Database Syst Rev. 2008
• Apaydin EA et al. A systematic review of St. John’s wort for major depressive disorder. Syst Rev. 2016;5(1):148
• Rahimi R et al. Efficacy and tolerability of Hypericum perforatum in MDD vs SSRIs: a meta-analysis. Prog Neuropsychopharmacol Biol Psychiatry. 2009;33(1):118-127
• StatPearls: St. John’s Wort (NCBI Bookshelf NBK557465)
• LactMed: St. John’s Wort (NCBI Bookshelf NBK501770)
• Hyperforin and CYP interactions: PMC6766782

Connections

• Compare anxiolytic herbs: Kava, Lavender, Passionflower
• Drug interaction context relevant to: Ginkgo (bleeding risk comparison)