What supplements should not be taken with a multivitamin?

Single mineral supplements (including calcium, zinc, magnesium, and potassium) should not be taken with a multivitamin. Single mineral supplements may interfere with the absorption of other minerals found in a multivitamin, like iron. For optimal absorption and maximum benefit, take your multivitamin a minimum of 2-3 hours before a calcium, zinc, magnesium, or potassium supplement.