NutriAudit

St. John's wort

St. John's Wort: High-Risk (Disables 50+ Medications)

St. John's wort induces CYP3A4, reducing birth control, warfarin, and HIV med effectiveness (FDA). Most dangerous supplement-drug interaction known.

St. John's wort (Hypericum perforatum) is one of the most interaction-heavy supplements because it induces CYP3A4 and P-glycoprotein, reducing levels of many prescription drugs, including hormonal contraceptives, HIV antiretrovirals, immunosuppressants, anticoagulants, and some antidepressants. The result can be unintended pregnancy, transplant rejection, or loss of infection control. This supplement should never be added casually to a medication stack. St John’s wort induces CYP450 and P-glycoprotein pathways, lowering levels of oral contraceptives, immunosuppressants, antiretrovirals, and many psychotropics, failure modes include transplant rejection and unintended pregnancy. Combining it with serotonergic antidepressants risks serotonin syndrome. Treat each bottle as a line item with dose, frequency, and ingredient form—not only a brand name. NutriAudit normalizes units, flags duplicate nutrient paths across products, and surfaces totals that approach tolerable upper intake levels from authoritative references. Use the export as a conversation starter with your clinician before surgery, pregnancy, new prescriptions, or whenever symptoms shift alongside product changes. Retail marketing and percent daily value lines do not replace summing the same vitamin or mineral across every source you actually take in a day. Proprietary blends still leave you responsible for recognizable vitamins and minerals underneath; photograph both the marketing panel and the Supplement Facts table when you open a new bottle so later dose reconstruction does not depend on memory alone. Kidney disease shifts the safety curve for magnesium, potassium, vitamin D metabolites, and some protein-adjacent supplement categories. Liver disease changes retinoid storage, clotting factor production, and detoxification capacity for concentrated herbal extracts. Malabsorption syndromes, bariatric anatomy, celiac disease, and inflammatory bowel flares change which forms and doses are appropriate even when a generic blog recommends a “standard” amount. Athletes may have higher turnover for some nutrients yet still face iron misadventure if they stack multiple iron paths without ferritin monitoring. None of these contexts are solved by buying a more expensive brand; they require individualized medical planning with periodic labs when indicated. Timing rules exist for specific drugs: levothyroxine separated from calcium, iron, and some supplements; bisphosphonates with strict water-only windows; fluoroquinolone and tetracycline antibiotics spaced away from divalent minerals. Those rules do not make the nutrients “bad”; they mean absorption competition is measurable. Conversely, vitamin C can be intentionally paired with non-heme iron under guidance, while calcium competes with iron for the same transporters. Magnesium and osmotic laxatives both draw water into the gut; combining them without awareness worsens cramping. Coffee and tea polyphenols blunt non-heme iron uptake at meals. A thoughtful schedule reduces side effects and makes adherence sustainable. Pregnancy and lactation introduce non-negotiable constraints for preformed vitamin A, high-dose vitamin D experiments, unstudied herbals, and casual use of “detox” or weight-loss blends. Pediatric dosing is not adult dosing scaled by intuition; gummy vitamins pose adherence and overdose tradeoffs depending on child access. Fertility stacks sometimes duplicate prenatal nutrients across multiple products until folic acid or iron totals exceed what obstetric clinicians intended. Postpartum recovery and breastfeeding change iodine, choline, DHA, and hydration needs, but random internet stacks rarely reconcile those variables with prescription prenatals. If you are pregnant, planning pregnancy, or feeding an infant, treat every new bottle as a question for your care team. Cost and pill burden influence adherence: elaborate twelve-product stacks often collapse into inconsistent use, creating irregular peaks and troughs that confuse both benefits and side effects. Consolidating to fewer, purpose-driven products under clinician guidance usually beats additive complexity. Subscription boxes and influencer bundles introduce new ingredients monthly, making causality impossible to track. A simple spreadsheet or NutriAudit export beats memory when you need to answer “what changed before this symptom started?” Keep start and stop dates whenever you add or remove a bottle. Vegan, vegetarian, and plant-forward diets shift priorities toward B12, iron, zinc, iodine, calcium, choline, and omega-3 strategies, but indiscriminate megadosing still violates ULs. Carnivore-adjacent or elimination diets may reduce folate and potassium diversity from foods, tempting users to compensate with stacks that overlap multis. Gluten-free packaged foods sometimes add fortification inconsistently compared with wheat-based staples. Cultural diets and fasting windows change meal timing and therefore mineral absorption planning. A stack audit anchored to actual food patterns beats copying a macro influencer who eats differently from you. NutriAudit encourages you to export a single stack summary for clinicians whenever totals approach reference limits or when new symptoms coincide with product changes. Revisit the audit after hospital discharge, a course of antibiotics, intentional weight loss, or any sustained diet pattern shift that changes what you eat every day.

St. John's wort: major interaction classes

Drug classRiskWhyAction
Birth controlContraceptive failureEnzyme inductionAvoid combination
HIV therapyVirologic failureReduced drug levelsNever combine
Transplant medsRejection riskLevel dropsNever combine
AntidepressantsSerotonin toxicity riskCombination variabilityPsychiatry guidance only

Source: NIH ODS (St. John’s wort); FDA interaction warnings for prescription medicines.

What should you know?

If you take any prescription, ask first.

This herb is not a “mood vitamin.”

Assume contraceptive failure.

Do not rely on pills/patch/ring if enzyme induction is present.

Emergency care for serotonin symptoms.

Agitation, fever, clonus, confusion are emergencies.

Tell every surgeon and anesthesiologist.

Herb discontinuation timing may be required.

Why this herb breaks stacks

Mood support blends and “natural antidepressant” marketing often hide St. John’s wort among other herbs.

NutriAudit helps users discover hidden St. John’s wort in proprietary blends before harm occurs.

CYP450 and P-gp induction, broad drug risk

St. John’s wort can reduce levels of oral contraceptives, immunosuppressants, anticoagulants, antiretrovirals, and many antidepressants, failure modes include pregnancy, transplant rejection, and subtherapeutic anticoagulation.

Induction persists for days after stopping; surgery and travel are bad moments to “trial” without pharmacy input.

Serotonin syndrome with antidepressants

Combining SJW with SSRIs/SNRIs/MAOIs/triptans is dangerous. “Natural” labeling does not reduce pharmacologic potency.

Phototoxic rashes and hypomania signals deserve discontinuation and clinician contact, not dose increases.

Common questions about supplement safety

1Is St. John’s wort safe for anxiety?

Safety is dominated by drug interactions, not the symptom label on the bottle.

2How long do interactions last?

Induction persists days to weeks after stopping, pharmacist half-life guidance matters.

3Can I take it with SSRIs?

Generally no, serotonin syndrome risk and interaction complexity.

4Does CBD replace it?

CBD has its own interaction profile, no swap without medical review.

Taking multiple supplements?

Use NutriAudit to audit your full stack for hidden overlaps.

Audit your supplement stack

Disclaimer: NutriAudit is a decision-support tool designed to help you review your supplement stack for potential duplicate, conflicting, or excessive ingredients. It is not a substitute for professional medical advice, diagnosis, or treatment. Always consult a qualified healthcare provider before making changes to your supplement routine, especially if you are pregnant, nursing, taking medications, or have a medical condition.

Based on reference standards from FDA, EFSA, TGA, and MHLW.

Last updated: 2026-04-07 · Data sourced from FDA Dietary Reference Intakes, EFSA Scientific Opinions, and NIH Office of Dietary Supplements where applicable.

Reviewed by NutriAudit editorial team. Based on public reference data from NIH ODS, FDA, EFSA, and other cited sources. Not medical advice.