Vitamins and Supplements You Should Never Mix

Copper and zinc

If you are taking copper supplements because of copper deficiency, avoid taking zinc at the same time, says Dr. Airey. “Zinc can help to boost the immune system but can interfere with your body’s absorption of copper. If you must take both, take them at least two hours apart.” Signs that you are still dealing with copper deficiency include fatigue, weakness, brittle bones, cold sensitivity and easy bruising.