Answered question
What supplements should not be taken together?
What supplements should not be taken together?
Iron, calcium, and zinc compete for absorption when taken in the same dose, so space them by at least two hours. Coffee and tea blunt iron uptake, so keep them apart. Most other common combinations are fine. When in doubt, check our interaction checker before combining new supplements.
Classic mineral conflicts
High-dose calcium reduces iron absorption sharply, and to a lesser extent zinc and magnesium. The cleanest fix is timing: iron in the morning on an empty stomach, calcium with a different meal. Multivitamins keep doses small enough that this matters less.
Stimulant and sedative overlaps
Caffeine plus high-dose B vitamins can feel jittery for sensitive people. Melatonin plus magnesium plus L-theanine in the same evening dose can feel heavier than expected. Build up one product at a time so you can tell what does what.
Medication interactions
St. John's wort, high-dose vitamin K, and grapefruit-related products can interact with prescription medications. Always check with a pharmacist or physician if you take prescription drugs, especially anticoagulants, thyroid medication, or antidepressants.