Supplement Interaction Checker
Check your supplements for known interactions, absorption conflicts, and optimal timing. Database of 38 supplements and 36 peer-reviewed interactions. Free tool — no sign-up required.
Select the supplements you currently take, then check for interactions.
Frequently Asked Questions
Which supplements should not be taken together?
Common conflicts include calcium and iron (calcium blocks iron absorption by up to 50%), zinc and copper (zinc inhibits copper absorption at high doses), and vitamin E with vitamin K (vitamin E can interfere with blood clotting). This checker analyzes your full supplement stack for all known interactions.
When is the best time to take supplements?
Fat-soluble vitamins (A, D, E, K) absorb best with a meal containing fat. Iron is best on an empty stomach. Magnesium and calcium should be taken at different times. B vitamins and CoQ10 are best in the morning as they can affect energy. This tool generates a personalized timing schedule.
How many interactions does this checker cover?
This tool covers 38 popular supplements and 36 documented interactions categorized as warnings (potentially harmful), positive synergies (better together), and informational notes. All interactions reference published research and clinical guidelines.
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