Check Your Supplements Against Your Medications
Scan any supplement label and see interaction flags for your prescriptions in seconds. Free on iOS.
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Free, evidence-based guides to the supplements you should avoid — or time carefully — with ten of the most prescribed medications in the United States. Every interaction listed is documented in NIH, MedlinePlus, or FDA references.
Supplement-drug interactions work three ways: some supplements make a medication too strong (bleeding-risk supplements with blood thinners), some make it too weak (St. John’s Wort speeding up drug elimination, calcium blocking levothyroxine absorption), and some stack the same effect from two directions (potassium with ACE inhibitors, berberine with diabetes drugs). Pick your medication below for the documented list — then verify your full stack with the free Suppi checker and your pharmacist.
This page is for informational purposes only and is not medical advice. The interactions listed here are well-documented but not exhaustive — no list can cover every product or personal situation. Always consult your doctor or pharmacist before combining any supplement with prescription medication, and never start or stop a medication or supplement based on what you read online.
Most people treat supplements and medications as separate worlds: the prescription comes from the doctor, the vitamins come from the store, and nobody cross-references the two. The numbers say that’s a mistake. The FDA receives over 50,000 adverse event reports related to dietary supplements each year, and the agency explicitly warns that combining supplements with medicines can cause harmful — even life-threatening — effects.
The mechanics are unglamorous but real. A supplement can bind a drug in your gut so it never reaches your bloodstream, the way calcium does to thyroid medication. It can speed up the liver enzymes that clear a drug, the way St. John’s Wort does to dozens of prescriptions — quietly deleting the protection you think you have. It can push the same physiological lever as your medication, the way potassium stacks with ACE inhibitors or berberine stacks with metformin. Or it can add a risk your drug already carries, the way fish oil and ginkgo add bleeding risk to anticoagulants.
What makes this gap dangerous is that nobody owns it. Supplement labels don’t warn about specific drugs. Prescription leaflets rarely name specific supplements. Doctors often don’t ask, and patients often don’t mention — surveys consistently find that a large share of supplement users never tell their physician what they take. The interactions on these pages are not obscure: every one is documented in NIH fact sheets, MedlinePlus drug information, or FDA safety communications. They are missed not because they’re unknown, but because nobody checked.
That’s the purpose of this hub: one guide per medication, covering only well-established interactions, with sources you can verify — plus a free tool that checks your whole stack at once.
Each guide covers the documented supplements to avoid, timing rules where separation solves the problem, supportive supplements where the drug depletes a nutrient, and cited references.
St. John's Wort and stimulant supplements are the documented risks with this seizure-threshold-lowering antidepressant.
The highest-stakes list in medicine: vitamin K consistency, St. John's Wort, fish oil, ginkgo, cranberry, and high-dose vitamin E.
Calcium, iron, and magnesium block absorption — separate by 4 hours — and biotin can skew your thyroid labs.
Stimulants like bitter orange and yohimbe fight the beta-blocker; licorice raises blood pressure; potassium needs bloodwork.
Avoid licorice root, watch potassium and sodium — and ask about supportive calcium and vitamin D for steroid bone loss.
St. John's Wort weakens clot protection; fish oil, ginkgo, and high-dose vitamin E add bleeding risk. Vitamin K is not the issue here.
Berberine stacks glucose-lowering on a potent drug, and slowed gastric emptying changes absorption timing.
St. John's Wort, 5-HTP, and tryptophan all raise serotonin on top of an SSRI — the serotonin syndrome trio.
Berberine doubles up on glucose-lowering — and long-term metformin depletes B12, a supplement you may actually need.
Potassium supplements and potassium-based salt substitutes risk hyperkalemia with ACE inhibitors.
Guides like these cover one medication at a time — but real routines are messier: three supplements, two prescriptions, a greens powder, and an electrolyte mix. Suppi’s supplement interaction checker cross-references every ingredient in your stack against your medications and each other, using a database built on 500+ peer-reviewed clinical studies. Scan a label, get flags in seconds, and bring the results to your doctor or pharmacist for the final word.
These guides cite only stable, authoritative references: NIH Office of Dietary Supplements fact sheets, MedlinePlus drug information from the National Library of Medicine, and FDA consumer safety pages. Interactions that are anecdotal, theoretical, or poorly documented are deliberately left out — an incomplete list you can trust beats a long one you can’t.
This page is for informational purposes only and is not medical advice. The interactions listed here are well-documented but not exhaustive — no list can cover every product or personal situation. Always consult your doctor or pharmacist before combining any supplement with prescription medication, and never start or stop a medication or supplement based on what you read online.
Scan any supplement label and see interaction flags for your prescriptions in seconds. Free on iOS.
Download Free on iOSPrefer to read first? See how the supplement interaction checker works.