Supplement Interaction Checker — Check Drug & Supplement Interactions

If you take medications and supplements, you’ve probably wondered: Are these safe together? Our supplement interaction checker helps you quickly spot potential drug–supplement conflicts, understand severity, and learn what kind of evidence supports each alert.

This tool page explains what the checker does, how to use it well, how we grade evidence, and where its limits are. The phrase supplement interaction checker appears here intentionally so you can find and recognize the tool you’re looking for.

What the Supplement Interaction Checker Does

• Screens your list of prescription meds, over‑the‑counter drugs, vitamins, minerals, herbs, botanicals, amino acids, and nutraceuticals for known or suspected interactions
• Flags interaction severity (major, moderate, minor) and the confidence level behind each alert (strong, moderate, emerging, or traditional use without modern trials)
• Explains likely mechanisms when known (for example, grapefruit’s furanocoumarins inhibit CYP3A4; calcium can chelate certain antibiotics and reduce absorption)
• Highlights timing considerations (e.g., “consider separating calcium and levothyroxine by at least 4 hours”) when evidence supports it
• Notes form and dose nuances (e.g., turmeric vs. concentrated curcumin extract; extended‑release vs. immediate‑release drugs)

The checker is designed to inform conversations with your clinician or pharmacist. It does not diagnose, treat, or replace professional advice.

How to Use the Supplement Interaction Checker (Step‑by‑Step)

1. Gather your list
   • Include all prescription medications, OTC drugs, and every supplement (vitamins, minerals, herbs, mushrooms, amino acids, oils, blends, and powders). List brand and form when possible (e.g., “curcumin 95% extract 500 mg,” “magnesium glycinate 200 mg”).
2. Enter items one by one
   • Use generic names when you can (e.g., “sertraline” instead of brand). The checker recognizes many brand names and synonyms, but generic names reduce ambiguity.
3. Add key details
   • Dose, frequency, and timing (morning/evening; with or without food)
   • Route (usually oral; note if transdermal, sublingual, etc.)
   • Special factors (extended‑release, enteric‑coated)
4. Review your dashboard
   • You’ll see interactions grouped by severity (major, moderate, minor) and evidence (strong, moderate, emerging, traditional). Each entry provides a short explanation and suggested next steps to discuss with your clinician, such as monitoring parameters or possible timing adjustments.
5. Explore mechanism notes
   • Learn whether it’s likely a pharmacokinetic issue (absorption, metabolism via CYP450/UGT enzymes, transporters like P‑gp) or a pharmacodynamic issue (additive sedation, bleeding risk, serotonin syndrome).
6. Save or export a summary
   • You can download an interaction report to share with your healthcare team. Avoid changing your regimen based solely on the report—use it to guide a professional conversation.

Tip: Be precise. “Turmeric” capsules vary widely; a concentrated curcumin extract can behave differently than culinary turmeric powder.

Common Supplement–Drug Interaction Examples and Severity Levels

These examples illustrate how the checker classifies risk and evidence. Always consider your unique context (dose, genetics, liver/kidney function, age, pregnancy, other conditions).

Major (avoid combination or use only with close medical supervision)

• St. John’s wort (Hypericum) + cyclosporine, tacrolimus, many HIV meds, some oral contraceptives, and certain statins
  • Mechanism: Potent induction of CYP3A4 and P‑gp can lower drug levels, risking treatment failure.
  • Evidence: Strong (multiple clinical studies and case reports).
• St. John’s wort + SSRIs/SNRIs/MAOIs
  • Mechanism: Additive serotonergic effects may precipitate serotonin syndrome.
  • Evidence: Moderate to strong (case reports, pharmacologic rationale; fewer RCTs).
• Grapefruit or Seville orange + simvastatin/lovastatin and some calcium channel blockers
  • Mechanism: Inhibition of intestinal CYP3A4 increases drug exposure.
  • Evidence: Strong (controlled PK studies).
• Kava (Piper methysticum) + benzodiazepines, barbiturates, or other sedatives
  • Mechanism: Additive CNS depression; rare hepatotoxicity concerns with kava itself.
  • Evidence: Moderate (human data for sedation; hepatotoxicity based on case reports and regulatory reviews).
• 5‑HTP or tryptophan + SSRIs/SNRIs/MAOIs
  • Mechanism: Increased serotonin risk.
  • Evidence: Emerging to moderate (case reports and mechanistic plausibility).

Moderate (use caution; monitor; consider timing changes)

• Warfarin + ginkgo, garlic, fish oil (high‑dose), or curcumin/turmeric extracts
  • Mechanism: Potential additive antiplatelet/anticoagulant effects; curcumin may affect CYPs/platelets.
  • Evidence: Mixed—ginkgo/garlic have case reports and observational data; fish oil RCTs show small bleeding time changes but limited clinical bleeding; curcumin evidence is emerging.
• CBD (cannabidiol) + clobazam, warfarin, or drugs metabolized by CYP2C19/CYP3A4
  • Mechanism: Enzyme inhibition can increase drug levels.
  • Evidence: Moderate (PK studies, clinical reports in epilepsy; case reports with warfarin/INR changes).
• Calcium, iron, magnesium, zinc + levothyroxine, tetracycline/quinolone antibiotics, bisphosphonates
  • Mechanism: Chelation or adsorption reduces absorption.
  • Evidence: Strong for several pairs (clinical PK and guideline recommendations). Timing separation is often advised.
• Ashwagandha + sedatives or thyroid medication
  • Mechanism: Possible additive sedation; rare reports of increased thyroid hormone activity.
  • Evidence: Emerging to moderate (limited human data; case reports).
• Niacin + statins
  • Mechanism: Increased risk of myopathy; additive effects on lipids and liver enzymes.
  • Evidence: Moderate (clinical experience, some RCT signal in combinations).
• Green tea (high intake) + nadolol
  • Mechanism: Reduced nadolol absorption via transporter effects.
  • Evidence: Moderate (small human studies).

Minor (usually manageable; often timing-related)

• Probiotics + antibiotics
  • Mechanism: Antibiotics can reduce probiotic viability; spacing may help.
  • Evidence: Moderate (numerous clinical trials on probiotics around antibiotics, though not all strains).
• Vitamin K in multivitamins + warfarin (stable low intake)
  • Mechanism: Pharmacodynamic opposition; small consistent intake may be acceptable.
  • Evidence: Moderate (guidelines emphasize consistency rather than avoidance).
• Caffeine (from green tea/guarana) + stimulant meds
  • Mechanism: Additive stimulation; monitor for jitteriness, heart rate.
  • Evidence: Moderate (physiologic rationale; limited controlled trials).

Traditional systems perspective: Many Traditional Chinese Medicine and Ayurveda formulas combine herbs intentionally. Historically, some pairings are thought to harmonize or moderate effects (traditional evidence). Our checker includes classical cautions when documented, and it flags possible modern pharmacologic conflicts (e.g., CYP interactions) when known.

How the Checker Works: Data Sources, Algorithm, and Evidence

• Data sources
  • Peer‑reviewed literature (clinical trials, pharmacokinetic studies, case reports)
  • Monographs and authoritative databases on natural medicines and drugs
  • Regulatory safety communications (FDA, EMA, Health Canada)
  • Pharmacopoeias and traditional texts (TCM, Ayurveda) for historical cautions
  • Adverse event databases (e.g., post‑marketing reports) with careful signal interpretation
• Normalization and mapping
  • Harmonizes brand names, generics, Latin binomials (e.g., Hypericum perforatum), and common synonyms
  • Distinguishes forms and extracts (standardized curcumin vs. turmeric powder; CBD isolate vs. full‑spectrum hemp)
• Mechanism engine
  • Pharmacokinetics: CYP450 (3A4, 2D6, 2C9, 2C19), UGT, P‑gp and other transporters, absorption pH, chelation
  • Pharmacodynamics: additive or opposing effects (sedation, bleeding risk, serotonergic tone, BP/HR changes)
• Severity and certainty scoring
  • Severity reflects clinical impact if the interaction occurs (major, moderate, minor)
  • Evidence level reflects research strength: strong (multiple RCTs/meta‑analyses or reproducible clinical PK studies), moderate (limited RCTs/observational/case series), emerging (preclinical, small human studies, plausible mechanisms), traditional (historical cautions without modern trials)
• Timing logic
  • For absorption interactions (e.g., iron with tetracyclines; calcium with levothyroxine), the checker suggests common separation windows derived from clinical guidance and PK data. These are prompts to discuss with your clinician.
• Continuous updates
  • Literature scanning and expert review inform periodic updates; new alerts may appear as emerging evidence accumulates.

What the Research Says

• Strong, replicated clinical evidence exists for several high‑impact interactions (e.g., grapefruit–statins; St. John’s wort–CYP3A4 substrates; calcium/iron with certain drugs).
• Many herb–drug interactions rely on mechanistic plausibility, small human PK studies, or case reports. These merit caution but often require individualized assessment.
• Bleeding‑related signals (ginkgo, garlic, fish oil) show mixed findings: physiologic changes are observed, yet large increases in major clinical bleeding are not consistently demonstrated in trials. Clinician monitoring remains prudent, especially with anticoagulants.
• Traditional texts sometimes flag herb pairings as incompatible. Modern pharmacology may explain some cautions (e.g., additive CNS effects), while others remain theoretical. We label these as traditional or emerging.

Safety, Limitations, and When to Contact a Healthcare Professional

Use extra caution and seek professional guidance if any of the following apply:

• You take anticoagulants/antiplatelets (warfarin, DOACs), anti‑rejection therapy, chemotherapy, antiretrovirals, antiepileptics, psychiatric medications, or narrow therapeutic index drugs
• You are pregnant, trying to conceive, or breastfeeding
• You have liver or kidney disease, significant cardiovascular disease, or are 65+
• You plan to start, stop, or change the dose/form of any supplement or medication

Important limitations:

• Proprietary blends vary. The checker may not know exact doses of each component, which affects risk.
• Genetic differences (CYP2D6, CYP2C19, etc.), gut microbiome, and comorbidities change interaction risk.
• Non‑oral routes (inhaled, topical, injectable) may not be fully covered.
• Rare, idiosyncratic reactions may not be predictable.
• Time‑of‑day and food interactions can modify risk but are not always captured in studies.

Never stop, start, or change a prescription medication based solely on an interaction alert. Share your report with a clinician or pharmacist.

Privacy, Data Handling, and Disclaimers

• Minimal data: The checker only needs the items you enter. We don’t require personal identifiers to run an interaction screen.
• Storage: Entries can be kept locally in your browser unless you choose to save to an account.
• Encryption: Data in transit is encrypted. If you create an account, stored data is encrypted at rest.
• Control: You can edit or delete your entries at any time. See our Privacy Policy for details.
• Research vs. advice: This tool is educational and not a substitute for professional medical advice, diagnosis, or treatment.

For more, visit: Privacy Policy, Terms of Use, and Editorial Policy.

FAQs and Troubleshooting

• How accurate is the supplement interaction checker?
  • Research‑based where possible. Strong for well‑studied pairs (e.g., grapefruit–statins), moderate to emerging for many herbs. We present severity and evidence separately so you can gauge confidence.
• How often is the database updated?
  • Regularly, with literature reviews and expert input. New alerts appear as evidence evolves.
• Does it cover Chinese and Ayurvedic formulas?
  • We include many common formulas and list their constituent herbs when known. Potency varies by manufacturer; use the notes field to specify extracts or percentages, and review both formula‑level and herb‑level interactions.
• What about brand names and blends?
  • We map many brands, but formulations change. If a brand isn’t recognized, enter the individual ingredients with doses.
• Can it advise exact timing to avoid all interactions?
  • For absorption‑type issues, common separation windows are suggested based on available evidence. For metabolic or pharmacodynamic interactions, timing may not fully mitigate risk—ask your clinician.
• Does it account for genetics or lab values (INR, drug levels)?
  • Not directly. These clinical data are essential for decision‑making and should be reviewed by your healthcare team.
• Are food interactions included?
  • Some high‑impact foods (grapefruit, Seville orange) are included. General diet patterns are not comprehensively mapped.
• What if my item isn’t found?
  • Try a generic name or the Latin binomial for herbs. Check spelling, remove special characters, or enter individual ingredients from a blend.
• Does it include essential oils or topical botanicals?
  • Coverage focuses on ingested products. Topical/inhaled exposures are partially supported and may be flagged when clinically relevant.

Practical Takeaways

• Keep an up‑to‑date list of all medications and supplements, including dose, form, and timing.
• Use the supplement interaction checker before starting a new product and after any change.
• Pay attention to both severity and evidence level in each alert.
• Share the exported report with your clinician or pharmacist before making changes.
• Be consistent with vitamin K intake if you take warfarin; consider spacing minerals away from thyroid meds and certain antibiotics.

Suggested Reading on GoldBamboo

• Herb–Drug Interactions: A Clinician’s Guide
• How to Talk to Your Doctor About Supplements
• Understanding CYP450: Why Grapefruit Matters

Disclaimer

This content and the supplement interaction checker are for educational purposes only and do not replace professional medical advice, diagnosis, or treatment. Always consult a qualified healthcare professional about your specific medications and supplements, especially before starting, stopping, or changing any product.