Supplement Interaction Checker 2026: Safety Tool (Free)

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Check known interactions between popular supplements and medications. Covers magnesium, zinc, vitamin D, K2, omega-3, ashwagandha, berberine, St. John’s Wort, ginkgo, ginseng, iron, melatonin and more. Severity-ranked: HIGH (avoid), MODERATE (take separately), LOW (informational).

Why This Tool Exists

Most supplement guides ignore drug interactions — yet 1 in 5 ER visits for adults 65+ involve supplement-drug interactions. Common deadly combinations: St. John’s Wort + SSRIs (serotonin syndrome), Vitamin K + warfarin (clotting issues), Ginkgo + blood thinners (bleeding), Ashwagandha + thyroid meds (TSH disruption).

How To Use

  1. Select the supplement you take (or plan to take)
  2. Review the interactions list ranked by severity
  3. If HIGH: discuss with doctor before combining
  4. If MODERATE: take supplement and medication 2-4 hours apart
  5. If LOW: just be aware, no action needed

Common High-Risk Combinations to Avoid

  • St. John’s Wort + SSRIs — serotonin syndrome risk (life-threatening)
  • Vitamin K + warfarin — reduces blood thinner effectiveness, clot risk
  • Ginkgo + blood thinners — increases bleeding risk
  • 5-HTP + SSRIs/MAOIs — serotonin syndrome
  • Kava + alcohol — liver damage
  • Berberine + diabetes meds — hypoglycemia risk

Important Disclaimer

This checker covers most common interactions but is NOT exhaustive. Pharmaceutical interaction databases (Lexicomp, Micromedex) have more complete coverage. Always:

  • Tell your doctor about ALL supplements you take
  • Tell your pharmacist about supplements when filling prescriptions
  • Stop all non-essential supplements 1-2 weeks before surgery
  • Never combine multiple sedatives without medical supervision

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Frequently Asked Questions

▸ Does this checker cover all supplement-drug interactions?
It covers 60+ common interactions across 18 popular supplements — the most clinically-significant. NOT exhaustive. For complete coverage, use pharmaceutical databases (Lexicomp, Micromedex) or consult a pharmacist.
▸ What do the severity levels mean?
HIGH (red) = AVOID combining without medical supervision. MODERATE (orange) = take supplement and medication 2-4 hours apart, OR monitor labs. LOW (yellow) = informational only, generally fine.
▸ What are the most dangerous supplement-medication combos?
St. John's Wort + SSRIs/MAOIs (serotonin syndrome — potentially fatal), Vitamin K + warfarin (clot risk), Ginkgo + blood thinners (bleeding), 5-HTP + SSRIs (serotonin syndrome), Kava + alcohol (liver damage), Berberine + diabetes meds (hypoglycemia).
▸ Should I stop supplements before surgery?
Yes — most supplements should be stopped 1-2 weeks before scheduled surgery. Especially: fish oil, vitamin E, ginkgo, garlic, ashwagandha (mild blood-pressure effects). Always tell your surgeon what you're taking.
▸ Can I rely on this tool alone?
No — it's a starting point. Always inform your doctor about ALL supplements you take. Tell your pharmacist when filling prescriptions. This tool covers common interactions but is NOT a substitute for personalized medical advice.