A Answers (1)
Michael Roizen, MD, Internal Medicine, answeredAlthough zinc deficiencies may cause various problems, boosting zinc beyond basic levels appears to do no good and may even cause harm. For example, too much zinc may interfere with the workings of another trace mineral you need, copper. As with most minerals, high intake may prove toxic, and too much zinc can damage the immune system. Take no more than 30 milligrams (mg) daily. (If you take 6 of the zinc cough drops -- the recommended max per day -- that's 80 mg).