Magnesium and calcium
When these minerals are taken at the same time, they may not be quite as effective, says Tod Cooperman, MD, president of consumerlab.com, an independent testing company focused on health and nutrition products in White Plains, New York. “Taking large amounts of minerals with other minerals will reduce absorption,” he says. In essence, the minerals compete with one another and both lose. Maximize your benefits by taking any mineral supplements at least two hours apart. This is one of the six things you should know before you begin taking magnesium supplements.