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Supplement and medication interaction checker
This is an educational list of interactions tied to a public source. It is not a complete medication review and it is not medical advice. Ask a pharmacist, or the clinician who prescribes the medicine, before you start, stop, or change a supplement. A pair that is missing here is not a safety clearance. SupplementScore takes no ads, sponsorships, or affiliate income. How this site is funded.
Pick a medicine, a supplement, or both. Each flag has a plain-language explanation and a link to NIH ODS, NCCIH, a regulator page, or a peer-reviewed review. We do not fill gaps with guesses.
The checker runs in your browser. It does not send the medicines you select to us.
Check a combination
Pick one or more medicines and one or more supplements. You can also pick just a medicine to see every cited flag for that group.
Guides by medicine
These pages are the same cited lists, written out so they can be read without running a script.
Warfarin (Coumadin, Jantoven) is sensitive to vitamin K and to several supplements that change clotting or the amount of drug in the blood. This page lists only pairs we can tie to a public source. Supplements to avoid with SSRIs
Selective serotonin reuptake inhibitors (SSRIs) and some other antidepressants do not mix safely with St. John's wort. The warning below is the pair we can cite. A short list is not a full medication review. Supplements to avoid with statins
Statins lower cholesterol. Two supplements have a cited problem next to them: red yeast rice, because it can contain the same chemical as lovastatin, and St. John's wort, which can weaken some statins. Supplements that interfere with thyroid medicine
Levothyroxine (Synthroid, Levoxyl, and similar tablets) is easy to block if a mineral is in the stomach at the same time. Biotin does not block the pill. It can make a thyroid blood test read wrong. Supplements and diabetes medicines
Berberine is sold as a blood-sugar supplement. In people with type 2 diabetes, a meta-analysis found that adding it to glucose-lowering drugs lowered blood sugar more than either one alone. That is a reason to tell the prescriber, not a reason to adjust a dose on your own. Supplements and blood pressure medicines
Blood pressure medicines are not one group. A potassium pill that is reasonable with a water pill that wastes potassium can be dangerous with a medicine that holds potassium in. Licorice root is a separate problem for people who already have high blood pressure. Supplements that can weaken birth control
St. John's wort can make birth control pills less effective. That is a cited interaction, and a failed pill is not a small side effect. Supplements and immunosuppressants
Medicines that suppress the immune system, including drugs that keep a transplanted organ from being rejected, are a bad place for guesswork. Two supplements have a cited note. Supplements to separate from antibiotics
Some antibiotics fail if a mineral binds them in the gut. The fix in the NIH fact sheets is to separate the doses, not to skip an antibiotic. Supplements and aspirin
Low-dose aspirin and other medicines that slow platelets already change bleeding. Two supplements have a cited extra warning. Licorice and corticosteroid medicines
NCCIH reports interactions between licorice and corticosteroid medicines such as prednisone. The page does not spell out every dose.