St. John's Wort
Also known as: Hypericum perforatum, Hypericum
St. John's wort (Hypericum perforatum) is one of the most-studied herbal supplements, most often discussed in the context of mood. NCCIH describes it as more effective than placebo and about as effective as standard antidepressants for mild-to-moderate depression, with limited evidence for other uses. The most important practical point is safety: it has major, wide-ranging drug interactions and can make many medications less effective, and combining it with antidepressants or other serotonergic drugs can cause serious effects. It is informational here — not a treatment, and not something to start, stop, or combine with medication on your own.
Snapshot
What this page can tell you: What NCCIH says about St. John's wort — its mild-to-moderate depression evidence and, most importantly, its major drug interactions and sun-sensitivity/pregnancy cautions.
What it cannot: That you should use it for depression or that it's safe with your medications — its interactions are extensive. This is a review-with-a-professional item, not a self-start one. Informational only.
🧩 Stack insights — how this fits into a schedule
Many medications (major interactions) — NCCIH: St. John's wort has major drug interactions — it can weaken birth control, warfarin, cyclosporine, some heart, HIV, cancer, seizure, and statin medications, and with antidepressants or other serotonergic drugs can cause serious serotonin-related effects. Review your full medication list with a clinician or pharmacist before considering it.
This is the defining caution for St. John's wort — do not change prescribed medication on your own.
Sun sensitivity and pregnancy — NCCIH: St. John's wort can cause severe skin reactions after sun exposure; it may be unsafe in pregnancy (birth-defect risk), and breastfeeding infants can experience colic, drowsiness, and lethargy.
Relationship insights are informational only — they describe what is commonly discussed or studied, not what you should take. Not medical advice; review your routine with a clinician or pharmacist.
🕒 Timing
When: With a meal
Food: With food
Commonly taken with food; timing is otherwise flexible. The medication-interaction review matters far more than timing.
💊 Common use range
Standardized extracts vary by product
No formal upper limit; the dominant concern is drug interactions, not the amount — follow product guidance and professional input.
Ranges are informational, not a recommended dose. Talk to a professional about what is right for you.
🤔 Worth considering?
Evidence vs. effort: Mixed evidence relative to burden
High-burden because of its interactions: NCCIH lists it weakening birth control, warfarin, cyclosporine, some heart, HIV, cancer, seizure, and statin medications, plus a serotonin-syndrome risk with antidepressants. This is one to review carefully with a clinician or pharmacist before considering, not to start on your own.
A general summary, not a recommendation. Whether something fits your situation is worth discussing with a healthcare professional.
⚠️ Commonly noted interactions (supplements)
None listed.
Often about absorption or timing rather than danger — separating doses is common. This list is not exhaustive.
🧭 Caution level
Ask a clinician or pharmacist before use.
- Pregnancy / breastfeeding caution
- Serotonergic (SSRI/SNRI) interaction
- MAOI medication interaction
- Anticoagulant (blood thinner) interaction
- Seizure-medication interaction
- Higher caution if you use hormonal therapy
- Immunosuppressant interaction
- Chemotherapy interaction
- Higher caution if you take a statin
Caution level is an informational summary of commonly discussed caution categories and doses — not a safety rating, approval, or medical advice. Low caution does not mean safe for you.
🩺 Medication caution categories
- Antidepressants (SSRIs/SNRIs)
- MAOIs
- Blood thinners (anticoagulants)
- Seizure medication
- Hormonal therapy
- Immunosuppressants
- Chemotherapy
- Statins
- Pregnancy or nursing (health condition)
🏥 Surgery & procedure caution
Because it interacts with many medications, tell your care team you use it well before any procedure; do not change prescribed medication on your own.
If you have a procedure scheduled, bring your full supplement list to your surgical and anesthesia team. Do not stop prescribed medication unless your clinician tells you to. Do not start or stop supplements based only on this app.
✅ Quality checklist
- Prefer products with third-party testing or a certificate of analysis (COA).
- Check the label for the exact form and the elemental or active amount per serving.
🧩 Commonly paired with
None listed.
🔁 Alternatives
None listed.
🗣️ Questions for a professional
- Given every medication I take, is St. John's wort safe to consider, or does it interact with any of them?
🛡️ Safety notes (source-reviewed)
- NCCIH: major drug interactions — weakens birth control, warfarin, cyclosporine, digoxin/ivabradine, some HIV (indinavir/nevirapine) and cancer (irinotecan/imatinib/docetaxel) drugs, seizure meds (phenytoin/carbamazepine), and simvastatin.
- With antidepressants or other serotonergic drugs, it can cause serious serotonin-related effects.
- Severe skin reactions after sun exposure; may be unsafe in pregnancy (birth defects); breastfeeding infants can have colic, drowsiness, lethargy.
⚖️ Evidence limitations
- NCCIH describes it as effective for mild-to-moderate depression, but the interaction profile makes professional review essential — do not change prescribed medication on your own.
❓ Frequently asked
Why is St. John's wort considered risky?
NCCIH lists major drug interactions — it can make many medications (birth control, warfarin, cyclosporine, some heart, HIV, cancer, seizure, and statin drugs) less effective, and with antidepressants it can cause serious serotonin-related effects. Review your full medication list with a clinician or pharmacist first.
Can I take St. John's wort with my antidepressant?
This is exactly the combination NCCIH flags for serious serotonin-related risk. Do not combine them or change your medication on your own — talk with your prescriber.
🔬 Evidence snapshot
NCCIH notes St. John's wort appears more effective than placebo and about as effective as standard antidepressants for mild-to-moderate depression, with limited evidence for other uses. Its defining issue is major, wide-ranging drug interactions — it can weaken many medications and, with serotonergic drugs, cause serious serotonin-related effects.
🚦 Commonly noted cautions (auto)
Pregnancy / nursing caution category. This item carries a pregnancy/nursing caution category. If you are pregnant, nursing, or planning pregnancy, consider discussing it with a healthcare professional. This is a general caution, not a diagnosis or medical instruction.
🧪 Forms & quality
Needs evidence review — no source-reviewed information yet. We only show dose and monitoring details after they have been checked against reputable sources.
See the supplement glossary for what form names like "L-", chelated, or standardized extract mean.
📏 Dose & monitoring
Evidence vs. burden: Mixed evidence relative to burden
😐 Commonly reported side effects
- Severe skin reactions after sun exposure (photosensitivity)
- Diarrhea, dizziness, trouble sleeping, restlessness, skin tingling
Non-exhaustive and individual.
🔄 Cycling & breaks
No established cycling pattern.
📅 Daily use notes
St. John's wort can weaken birth control, warfarin, cyclosporine, digoxin/ivabradine, some HIV and cancer drugs, seizure medicines, and statins, and can raise serotonin-related risks with antidepressants. Review your full medication list with a clinician or pharmacist before considering it.
📋 Source review status
Source-reviewed — last reviewed 2026-07-03
Reviewed against the NCCIH St. John's wort page; editorial pass still pending.
Research backlog (queries to verify):
- St John's wort drug interaction CYP3A4 P-glycoprotein induction
- St John's wort serotonin syndrome antidepressant case reports
📚 References
- NCCIH — St. John's WortNCCIH — Verified mild-to-moderate depression evidence; major drug interactions (amitriptyline, bupropion, birth control, cyclosporine, phenytoin/carbamazepine, digoxin/ivabradine, indinavir/nevirapine, irinotecan/imatinib/docetaxel, warfarin, simvastatin); serotonin-syndrome risk; photosensitivity and other side effects; pregnancy birth-defect risk and breastfeeding colic/drowsiness.
Verified against the source shown. See the research-status page for how review works.
Use the web planner · StackWise (Android) in closed testing →