St. John’s Wort: The Definitive Guide

What is St. John's wort?

St. John's wort is Hypericum perforatum, a yellow-flowered plant used in standardized extracts and less-characterized retail products. It is promoted mainly for depression. A botanical label does not make it a low-interaction treatment. [3], [4]

The best synthesis supports a benefit signal in mild-to-moderate depression, not severe disease or self-managed crisis care. Interaction risk can outweigh that possible benefit before the first dose. [1], [3]

Typical St. John's Wort Protocols

There is no RDA, AI or established UL; milligrams are not interchangeable across extracts.

Titration

No validated self-titration; interaction magnitude can change with the product.

Timing

No universal timing; follow only a prescribed schedule.

Duration

Efficacy beyond 12 weeks remains uncertain.

Stopping

Coordinate stopping because other medicine concentrations may rebound.

What is St. John's wort commonly used for?

It is promoted mainly for depression. Evidence for menopause, ADHD, OCD, irritable bowel syndrome and smoking cessation is insufficient. [3]

Which form and label details matter?

Record Hypericum perforatum, extract name, hypericin and hyperforin if stated, daily total and every medicine. Higher-hyperforin products may cause stronger enzyme induction. [4]

What does the human evidence show?

Mild and moderate depression

Apaydin and colleagues included 35 studies and 6,993 participants. Compared with placebo, St. John's wort produced more responders (RR 1.53, 95% CI 1.19–1.97; 18 trials), but heterogeneity was high (I² 79%). Compared with antidepressants, response did not significantly differ (RR 1.01, 95% CI 0.90–1.14). Evidence quality was moderate, adverse-event reporting was limited and rare events were not assessed. [1]

Major trial and severity limits

The 2002 JAMA trial randomized 340 adults with major depression to LI-160, sertraline or placebo for eight weeks. Neither active arm separated from placebo on the two primary outcomes. St. John's wort used 900–1,500 mg/day based on response; the abstract does not report within-day frequency. [2]

NCCIH concludes that mild-to-moderate depression may improve, while severe depression and use beyond 12 weeks remain uncertain. Depression can be serious and needs assessment, particularly with suicidality, psychosis or mania. [3]

How might it work?

Hyperforin and hypericin are studied markers. Neurotransmitter effects are proposed, while hyperforin activates pathways involved in enzyme induction. Mechanism does not predict benefit and constituent levels vary. [4]

What are the risks and interactions?

St. John's wort induces drug-metabolizing enzymes and transporters, especially CYP3A4 and P-glycoprotein; induction strength correlates with hyperforin content. It can reduce exposure to cyclosporine, oral contraceptives, warfarin, digoxin, some HIV and cancer medicines, anticonvulsants and some statins. [3], [4]

Combining it with antidepressants or other serotonergic medicines can cause serious serotonin toxicity. It may worsen mania or psychosis in susceptible people. Photosensitivity, diarrhea, dizziness, insomnia, restlessness and tingling can occur. Pregnancy may carry birth-defect risk; breastfed infants have had colic, drowsiness and lethargy. [3]

Seek urgent care for suicidal intent, severe agitation, hallucinations, mania, high fever, marked tremor, rigid muscles, seizure, fainting, breathing difficulty or a severe sun-related skin reaction.

Legal status in the United States and Canada

In the United States, it is not an FDA-approved depression treatment.

In Canada, an NPN is product specific and does not establish extract equivalence or compatibility with medicines.

What should you monitor?

Record extract, total, dates, mood, sleep, agitation, mania, photosensitivity and the complete medicine list. A crisis plan takes priority over an app.

What happens when you stop?

No predictable withdrawal is established, but enzyme induction recedes and can raise exposure to other medicines. Coordinate stopping.

How should it be stored?

Keep sealed, dry, away from heat and children. Follow label instructions for protection from light.

How does it compare with other approaches?

St. John’s wort is not an SSRI, psychotherapy, light therapy or crisis care. Those approaches have different evidence, quality controls and monitoring.

What do public communities add?

Public reports flag insomnia, photosensitivity and unexpected interactions. They cannot establish efficacy, hyperforin content or medicine compatibility.

Common questions

Does St. John’s wort treat depression?

A benefit signal exists for mild-to-moderate depression, but it is not established for severe depression and should not replace diagnosis or crisis care. [1], [3]

Is it as effective as an antidepressant?

Pooled trials found no response difference, but heterogeneity, product differences and limited severe-depression evidence prevent simple equivalence. [1]

Why are interactions so important?

Enzyme and transporter induction can lower exposure to medicines with life-critical effects. [3], [4]

Can it reduce birth-control effectiveness?

Yes. NCCIH lists birth control pills among medicines whose effect can be weakened. [3]

Can it be combined with an SSRI?

Not without prescriber direction; serotonin toxicity can be serious. [3]

Can I stop it suddenly?

No withdrawal taper is established, but stopping can change other medicine levels as induction recedes. Coordinate with a pharmacist or prescriber.

Is it safe during pregnancy or breastfeeding?

NCCIH describes potential pregnancy risk and reported infant effects during breastfeeding. Avoid unsupervised use. [3]

Should it be cycled?

No evidence-based on/off cycling schedule is established.

Glossary

Terms used in this guide.

Hyperforin

A constituent associated with enzyme and transporter induction.

CYP3A4

An enzyme that metabolizes many medicines.

P-glycoprotein

A transporter that can reduce exposure to some medicines.

Serotonin toxicity

A potentially life-threatening syndrome from excessive serotonergic activity.

Mania

An abnormally elevated or irritable mood state with increased activation.

Titration

Changing an amount in planned steps; no general self-titration is established.

How this guide was researched

This draft prioritized the comprehensive systematic review, JAMA primary trial, May 2025 NCCIH fact sheet and hyperforin interaction review. Corrections narrow benefit to mild-to-moderate depression and put interactions first. Evidence was refreshed October 9, 2026.

How this guide was made

The ledger records product, population, schedule, outcome and access level.

Sources

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